Simple database: Difference between revisions
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item5,2014-06-03 19:30:23,cat3</pre> |
item5,2014-06-03 19:30:23,cat3</pre> |
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=={{header|Perl}}== |
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<lang Perl>#!/usr/bin/perl |
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use warnings; |
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use strict; |
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use feature qw{ say }; |
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use JSON::PP; |
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use Time::Piece; |
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use constant { |
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NAME => 0, |
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CATEGORY => 1, |
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DATE => 2, |
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DB => 'simple-db', |
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}; |
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my $operation = shift // ""; |
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my %dispatch = ( |
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n => \&add_new, |
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l => \&print_latest, |
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L => \&print_latest_for_categories, |
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a => \&print_all, |
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); |
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if ($dispatch{$operation}) { |
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$dispatch{$operation}->(@ARGV); |
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} else { |
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die "Invalid option. Use one of n, l, L, a.\n" |
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} |
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sub add_new { |
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my ($name, $category, $date) = @_; |
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my $db = eval { load() } || {}; |
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if (defined $date) { |
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eval { 'Time::Piece'->strptime($date, '%Y-%m-%d'); 1 } |
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or die "Invalid date format: YYYY-MM-DD.\n"; |
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} else { |
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$date //= localtime->ymd; |
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} |
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my @ids = keys %{ $db->{by_id} }; |
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my $max_id = max(num => @ids) || 0; |
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$db->{by_id}{ ++$max_id } = [ $name, $category, $date ]; |
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save($db); |
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} |
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sub print_latest { |
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build_indexes( my $db = load(), 0, 1 ); |
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_print_latest($db); |
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} |
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sub _print_latest { |
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my ($db, $category) = @_; |
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my @dates = keys %{ $db->{by_date} }; |
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@dates = grep { |
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grep $db->{by_id}{$_}[CATEGORY] eq $category, |
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@{ $db->{by_date}{$_} }; |
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} @dates if defined $category; |
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my $last_date = max(str => @dates); |
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say for map $db->{by_id}{$_}[NAME], |
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grep ! defined $category |
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|| $db->{by_id}{$_}[CATEGORY] eq $category, |
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@{ $db->{by_date}{$last_date} }; |
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} |
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sub max { |
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my $type = shift; |
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my $max = $_[0]; |
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{ num => sub { $_ > $max }, |
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str => sub { $_ gt $max}, |
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}->{$type}->() and $max = $_ |
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for @_[ 1 .. $#_ ]; |
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return $max |
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} |
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sub print_latest_for_categories { |
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build_indexes( my $db = load(), 1, 1 ); |
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for my $category (sort keys %{ $db->{by_category} }){ |
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say "* $category"; |
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_print_latest($db, $category); |
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} |
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} |
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sub print_all { |
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build_indexes( my $db = load(), 0, 1 ); |
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for my $date (sort keys %{ $db->{by_date} }) { |
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for my $id (@{ $db->{by_date}{$date} }) { |
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say $db->{by_id}{$id}[NAME]; |
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} |
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} |
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} |
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sub load { |
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open my $in, '<', DB or die "Can't open database: $!\n"; |
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local $/; |
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return { by_id => decode_json(<$in>) }; |
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} |
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sub save { |
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my ($db) = @_; |
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open my $out, '>', DB or die "Can't save database: $!\n"; |
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print {$out} encode_json($db->{by_id}); |
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close $out; |
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} |
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sub build_indexes { |
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my ($db, $by_category, $by_date) = @_; |
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for my $id (keys %{ $db->{by_id} }) { |
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push @{ $db->{by_category}{ $db->{by_id}{$id}[CATEGORY] } }, $id |
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if $by_category; |
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push @{ $db->{by_date}{ $db->{by_id}{$id}[DATE] } }, $id |
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if $by_date; |
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} |
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}</lang> |
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Sample session<pre> ~ $ db.pl n 'Donald Trump' Republican 2017-01-20 |
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~ $ db.pl n 'Barack Obama' Democratic 2009-01-20 |
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~ $ db.pl n 'Bill Clinton' Democratic 1993-01-20 |
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~ $ db.pl n 'George W. Bush' Republican 2001-01-20 |
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~ $ db.pl a |
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Bill Clinton |
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George W. Bush |
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Barack Obama |
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Donald Trump |
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~ $ db.pl l |
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Donald Trump |
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~ $ db.pl L |
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* Democratic |
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Barack Obama |
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* Republican |
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Donald Trump</pre> |
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=={{header|Phix}}== |
=={{header|Phix}}== |
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Revision as of 20:55, 17 February 2018
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Write a simple tool to track a small set of data.
The tool should have a command-line interface to enter at least two different values.
The entered data should be stored in a structured format and saved to disk.
It does not matter what kind of data is being tracked. It could be a collection (CDs, coins, baseball cards, books), a diary, an electronic organizer (birthdays/anniversaries/phone numbers/addresses), etc.
You should track the following details:
- A description of the item. (e.g., title, name)
- A category or tag (genre, topic, relationship such as “friend” or “family”)
- A date (either the date when the entry was made or some other date that is meaningful, like the birthday); the date may be generated or entered manually
- Other optional fields
The command should support the following Command-line arguments to run:
- Add a new entry
- Print the latest entry
- Print the latest entry for each category
- Print all entries sorted by a date
The category may be realized as a tag or as structure (by making all entries in that category subitems)
The file format on disk should be human readable, but it need not be standardized. A natively available format that doesn't need an external library is preferred. Avoid developing your own format if you can use an already existing one. If there is no existing format available, pick one of:
- Related task
Bracmat
This is a rather minimal solution. The program is run from the command line of the operating system, in this example the Windows command prompt. The program is stored in a file called 'sdb': <lang bracmat> whl ' ( arg$:?command
& ( get'db
| (db=1)&lst$(db,db,NEW)
)
& !command
: ( add
& :?name:?tag:?date
& whl
' ( arg$:?argmnt
& arg$:?value
& (!argmnt.!value)
: ( (title|name.?name)
| (category|tag.?tag)
| (date.?date)
)
)
& ( !name:~
& !tag:~
& !date:~
& ( !db:?*!tag^(?+(!date.!name)+?)*?
& out$"This record already exists"
| !tag^(!date.!name)*!db:?db
& lst$(db,db,NEW)
)
| out$"invalid data"
)
| latest
& :?date
& nothing found:?latest
& ( !db
: ?
* ?tag
^ ( ?
+ ( (>!date:?date.?name)
& (!name,!tag,!date):?latest
& ~
)
+ ?
)
* ?
| out$!latest
)
| latest/category
& :?date:?latests:?latest
& ( !db
: ?
* ( ?tag
& !latests !latest:?latests
& :?latest:?date
)
^ ( ?
+ ( (>!date:?date.?name)
& (!name,!tag,!date):?latest
& ~
)
+ ?
)
* ?
| !latests !latest:?latests&out$!latests
)
| sorted
& 0:?sorted
& ( !db
: ?
* ?tag
^ ( ?
+ ( (?date.?name)
& (!date.!name,!tag,!date)+!sorted:?sorted
& ~
)
+ ?
)
* ?
| whl
' (!sorted:(?.?row)+?sorted&out$!row)
)
)
);
</lang> First we add some records, a some ships that arrived at the harbour in Rotterdam today.
bracmat "get$sdb" add name "CORONA BULKER" tag "BULK CARRIER" date "2014.10.21.04:00" bracmat "get$sdb" add name "FPMC 21" tag "CHEMICAL TANKER" date "2014.10.15.12:00" bracmat "get$sdb" add name "CHINA PROGRESS" tag "BULK CARRIER" date "2014.10.13.22:00" bracmat "get$sdb" add name "FAIRCHEM YUKA" tag "CHEMICAL TANKER" date "2014.10.13.12:00" bracmat "get$sdb" add name "NAVE COSMOS" tag "CHEMICAL TANKER" date "2014.10.13.10:00" bracmat "get$sdb" add name "GOLDEN ICE" tag "BULK CARRIER" date "2014.10.10.12:00" bracmat "get$sdb" add name "GHAZAL" tag "CRUDE OIL" date "2014.10.10.12:00" bracmat "get$sdb" add name "HS MEDEA" tag "CRUDE OIL" date "2014.10.10.02:00"
Instead of 'name' you can use 'title' and instead of 'tag' you can use 'category'. The date has to be year first and day last, followed by time information if you like. No attempt is made to validate the date/time. Now the queries:
prompt> bracmat "get$sdb" latest CORONA BULKER,BULK CARRIER,2014.10.21.04:00 prompt> bracmat "get$sdb" latest/category (CORONA BULKER,BULK CARRIER,2014.10.21.04:00) (FPMC 21,CHEMICAL TANKER,2014.10.15.12:00) (GHAZAL,CRUDE OIL,2014.10.10.12:00) prompt> bracmat "get$sdb" sorted HS MEDEA,CRUDE OIL,2014.10.10.02:00 GHAZAL,CRUDE OIL,2014.10.10.12:00 GOLDEN ICE,BULK CARRIER,2014.10.10.12:00 NAVE COSMOS,CHEMICAL TANKER,2014.10.13.10:00 FAIRCHEM YUKA,CHEMICAL TANKER,2014.10.13.12:00 CHINA PROGRESS,BULK CARRIER,2014.10.13.22:00 FPMC 21,CHEMICAL TANKER,2014.10.15.12:00 CORONA BULKER,BULK CARRIER,2014.10.21.04:00
The database file 'db' looks like this:
db= "BULK CARRIER"
^ ( ("2014.10.10.12:00"."GOLDEN ICE")
+ ("2014.10.13.22:00"."CHINA PROGRESS")
+ ("2014.10.21.04:00"."CORONA BULKER")
)
* "CHEMICAL TANKER"
^ ( ("2014.10.13.10:00"."NAVE COSMOS")
+ ("2014.10.13.12:00"."FAIRCHEM YUKA")
+ ("2014.10.15.12:00"."FPMC 21")
)
* "CRUDE OIL"^(("2014.10.10.02:00"."HS MEDEA")+("2014.10.10.12:00".GHAZAL));
Use is made of Bracmat's automatic normalization of algebraic formula to turn the data into a hierarchical structure, with the tag as the top level and the date/time immediately below that level.
C
A simple database in C with some error checking, even. A quick test with Valgrind revealed no obvious memory leaks. The following data was used for testing. -> database.csv
"Soon Rising","Dee","Lesace","10-12-2000","New Hat Press" "Brave Chicken","Tang","Owe","04-01-2008","Nowhere Press" "Aardvark Point","Dee","Lesace","5-24-2001","New Hat Press" "Bat Whisperer, The","Tang","Owe","01-03-2004","Nowhere Press" "Treasure Beach","Argus","Jemky","09-22-1999","Lancast"
<lang C>#include <stdio.h>
- include <stdlib.h> /* malloc */
- include <string.h> /* strlen */
- define _XOPEN_SOURCE /* requred for time functions */
- define __USE_XOPEN
- include <time.h>
- define DB "database.csv" /* database name */
- define TRY(a) if (!(a)) {perror(#a);exit(1);}
- define TRY2(a) if((a)<0) {perror(#a);exit(1);}
- define FREE(a) if(a) {free(a);a=NULL;}
- define sort_by(foo) \
static int by_##foo (const void*p1, const void*p2) { \
return strcmp ((*(const pdb_t*)p1)->foo, (*(const pdb_t*)p2)->foo); }
typedef struct db {
char title[26]; char first_name[26]; char last_name[26]; time_t date; char publ[100]; struct db *next;
} db_t,*pdb_t; typedef int (sort)(const void*, const void*); enum {CREATE,PRINT,TITLE,DATE,AUTH,READLINE,READ,SORT,DESTROY}; static pdb_t dao (int cmd, FILE *f, pdb_t db, sort sortby); static char *time2str (time_t *time); static time_t str2time (char *date); /* qsort callbacks */ sort_by(last_name); sort_by(title); static int by_date(pdb_t *p1, pdb_t *p2); /* main */ int main (int argc, char **argv) {
char buf[100];
const char *commands[]={"-c", "-p", "-t", "-d", "-a", NULL};
db_t db;
db.next=NULL;
pdb_t dblist;
int i;
FILE *f;
TRY (f=fopen(DB,"a+"));
if (argc<2) {
usage: printf ("Usage: %s [commands]\n"
"-c Create new entry.\n"
"-p Print the latest entry.\n"
"-t Print all entries sorted by title.\n"
"-d Print all entries sorted by date.\n"
"-a Print all entries sorted by author.\n",argv[0]);
fclose (f);
return 0;
}
for (i=0;commands[i]&&strcmp(argv[1],commands[i]);i++);
switch (i) {
case CREATE:
printf("-c Create a new entry.\n");
printf("Title :");if((scanf(" %25[^\n]",db.title ))<0)break;
printf("Author Firstname:");if((scanf(" %25[^\n]",db.first_name))<0)break;
printf("Author Lastname :");if((scanf(" %25[^\n]",db.last_name ))<0)break;
printf("Date 10-12-2000 :");if((scanf(" %10[^\n]",buf ))<0)break;
printf("Publication :");if((scanf(" %99[^\n]",db.publ ))<0)break;
db.date=str2time (buf);
dao (CREATE,f,&db,NULL);
break;
case PRINT:
printf ("-p Print the latest entry.\n");
while (!feof(f)) dao (READLINE,f,&db,NULL);
dao (PRINT,f,&db,NULL);
break;
case TITLE:
printf ("-t Print all entries sorted by title.\n");
dblist = dao (READ,f,&db,NULL);
dblist = dao (SORT,f,dblist,by_title);
dao (PRINT,f,dblist,NULL);
dao (DESTROY,f,dblist,NULL);
break;
case DATE:
printf ("-d Print all entries sorted by date.\n");
dblist = dao (READ,f,&db,NULL);
dblist = dao (SORT,f,dblist,(int (*)(const void *,const void *)) by_date);
dao (PRINT,f,dblist,NULL);
dao (DESTROY,f,dblist,NULL);
break;
case AUTH:
printf ("-a Print all entries sorted by author.\n");
dblist = dao (READ,f,&db,NULL);
dblist = dao (SORT,f,dblist,by_last_name);
dao (PRINT,f,dblist,NULL);
dao (DESTROY,f,dblist,NULL);
break;
default: {
printf ("Unknown command: %s.\n",strlen(argv[1])<10?argv[1]:"");
goto usage;
} }
fclose (f);
return 0;
} /* Data Access Object (DAO) */ static pdb_t dao (int cmd, FILE *f, pdb_t in_db, sort sortby) {
pdb_t *pdb=NULL,rec=NULL,hd=NULL;
int i=0,ret;
char buf[100];
switch (cmd) {
case CREATE:
fprintf (f,"\"%s\",",in_db->title);
fprintf (f,"\"%s\",",in_db->first_name);
fprintf (f,"\"%s\",",in_db->last_name);
fprintf (f,"\"%s\",",time2str(&in_db->date));
fprintf (f,"\"%s\" \n",in_db->publ);
break;
case PRINT:
for (;in_db;i++) {
printf ("Title : %s\n", in_db->title);
printf ("Author : %s %s\n", in_db->first_name, in_db->last_name);
printf ("Date : %s\n", time2str(&in_db->date));
printf ("Publication : %s\n\n", in_db->publ);
if (!((i+1)%3)) {
printf ("Press Enter to continue.\n");
ret = scanf ("%*[^\n]");
if (ret<0) return rec; /* handle EOF */
else getchar();
}
in_db=in_db->next;
}
break;
case READLINE:
if((fscanf(f," \"%[^\"]\",",in_db->title ))<0)break;
if((fscanf(f," \"%[^\"]\",",in_db->first_name))<0)break;
if((fscanf(f," \"%[^\"]\",",in_db->last_name ))<0)break;
if((fscanf(f," \"%[^\"]\",",buf ))<0)break;
if((fscanf(f," \"%[^\"]\" ",in_db->publ ))<0)break;
in_db->date=str2time (buf);
break;
case READ:
while (!feof(f)) {
dao (READLINE,f,in_db,NULL);
TRY (rec=malloc(sizeof(db_t)));
*rec=*in_db; /* copy contents */
rec->next=hd;/* to linked list */
hd=rec;i++;
}
if (i<2) {
puts ("Empty database. Please create some entries.");
fclose (f);
exit (0);
}
break;
case SORT:
rec=in_db;
for (;in_db;i++) in_db=in_db->next;
TRY (pdb=malloc(i*sizeof(pdb_t)));
in_db=rec;
for (i=0;in_db;i++) {
pdb[i]=in_db;
in_db=in_db->next;
}
qsort (pdb,i,sizeof in_db,sortby);
pdb[i-1]->next=NULL;
for (i=i-1;i;i--) {
pdb[i-1]->next=pdb[i];
}
rec=pdb[0];
FREE (pdb);
pdb=NULL;
break;
case DESTROY: {
while ((rec=in_db)) {
in_db=in_db->next;
FREE (rec);
} } }
return rec;
} /* convert numeric time to date string */ static char *time2str (time_t *time) {
static char buf[255]; struct tm *ptm; ptm=localtime (time); strftime(buf, 255, "%m-%d-%Y", ptm); return buf;
} /* convert date string to numeric time */ static time_t str2time (char *date) {
struct tm tm; memset (&tm, 0, sizeof(struct tm)); strptime(date, "%m-%d-%Y", &tm); return mktime(&tm);
} /* sort by date callback for qsort */ static int by_date (pdb_t *p1, pdb_t *p2) {
if ((*p1)->date < (*p2)->date) {
return -1;
}
else return ((*p1)->date > (*p2)->date);
}</lang>
COBOL
This is a souped-up version of the task from Take notes on the command line. It stores the current date, a tag, a title and a note as an entry in a file. The database produced is not particularly human-readable or easy to modify, but it is in a well-structured format.
<lang cobol> IDENTIFICATION DIVISION.
PROGRAM-ID. simple-database.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT OPTIONAL database-file ASSIGN Database-Path
ORGANIZATION INDEXED
ACCESS SEQUENTIAL
RECORD KEY data-title
ALTERNATE RECORD KEY data-tag
WITH DUPLICATES
ALTERNATE RECORD KEY date-added
WITH DUPLICATES
FILE STATUS file-status
.
DATA DIVISION.
FILE SECTION.
FD database-file.
01 database-record.
*> Date is in YYYYMMDD format.
03 date-added PIC 9(8).
03 data-tag PIC X(20).
03 data-title PIC X(50).
03 data-contents PIC X(200).
*> Adding extra space is considered good style so the record
*> can be expanded in the future.
03 FILLER PIC X(50).
WORKING-STORAGE SECTION.
78 Database-Path VALUE "database.dat".
01 file-status PIC XX.
88 file-ok VALUE "00".
88 duplicate-key VALUE "22".
88 key-not-found VALUE "23".
01 num-args PIC 99.
01 action PIC XX.
88 create-entry VALUE "-c".
88 remove-entry VALUE "-r".
88 find-entry VALUE "-f".
88 print-latest VALUE "-l".
88 print-database VALUES "-a", "-d", "-t".
*> Printed by title.
88 print-by-title VALUE "-a".
88 print-by-date VALUE "-d".
88 print-by-tag VALUE "-t".
88 print-help VALUES "-h", SPACES.
01 read-direction-flag PIC X VALUE SPACE.
88 read-backwards VALUE "B".
01 edited-date PIC 9(4)/99/99.
PROCEDURE DIVISION.
DECLARATIVES.
database-file-error SECTION.
USE AFTER ERROR ON database-file
DISPLAY "An error has occurred while using " Database-Path
". Error no. " file-status
DISPLAY "The program will terminate."
CLOSE database-file
GOBACK
.
END DECLARATIVES.
main-line.
DISPLAY 1 UPON ARGUMENT-NUMBER
ACCEPT action FROM ARGUMENT-VALUE
ACCEPT num-args FROM ARGUMENT-NUMBER
EVALUATE TRUE
WHEN create-entry
IF num-args >= 4
PERFORM write-entry
ELSE
DISPLAY "-a requires arguments to enter in the "
"database. See help (-h) for details."
END-IF
WHEN remove-entry
IF num-args >= 2
PERFORM delete-entry
ELSE
DISPLAY "-r requires the title of the entry to "
"delete."
END-IF
WHEN find-entry
IF num-args >= 2
PERFORM display-specified-entry
ELSE
DISPLAY "-f requires the title of the entry to "
"find."
END-IF
WHEN print-latest
PERFORM show-latest
WHEN print-database
PERFORM show-database
WHEN print-help
PERFORM show-general-help
WHEN OTHER
DISPLAY action " is not a valid option."
END-EVALUATE
GOBACK
.
write-entry.
OPEN EXTEND database-file
DISPLAY 2 UPON ARGUMENT-NUMBER
ACCEPT data-tag FROM ARGUMENT-VALUE
DISPLAY 3 UPON ARGUMENT-NUMBER
ACCEPT data-title FROM ARGUMENT-VALUE
IF data-title = SPACES
DISPLAY "The title cannot be blank."
PERFORM close-and-terminate
END-IF
DISPLAY 4 UPON ARGUMENT-NUMBER
ACCEPT data-contents FROM ARGUMENT-VALUE
ACCEPT date-added FROM DATE YYYYMMDD
WRITE database-record
INVALID KEY
IF duplicate-key
DISPLAY "An entry in the database already has "
"that title. Please choose a different "
"title or remove the entry."
ELSE
PERFORM database-file-error
END-IF
END-WRITE
PERFORM close-database
.
delete-entry.
PERFORM get-title-arg
OPEN I-O database-file
PERFORM read-title
DELETE database-file
PERFORM close-database
.
display-specified-entry.
PERFORM get-title-arg
OPEN INPUT database-file
PERFORM read-title
PERFORM show-record
PERFORM close-database
.
get-title-arg.
DISPLAY 2 UPON ARGUMENT-NUMBER
ACCEPT data-title FROM ARGUMENT-VALUE
.
read-title.
START database-file KEY IS = data-title
INVALID KEY
IF key-not-found
DISPLAY "An entry with that title was not found."
PERFORM close-and-terminate
ELSE
PERFORM database-file-error
END-IF
END-START
READ database-file
.
close-and-terminate.
PERFORM close-database
GOBACK
.
show-latest.
OPEN INPUT database-file
PERFORM start-at-last-date
READ database-file
PERFORM show-record
PERFORM close-database
.
show-database.
OPEN INPUT database-file
EVALUATE TRUE
WHEN print-by-title
*> Primary key is the title.
CONTINUE
WHEN print-by-tag
MOVE LOW-VALUES TO data-tag
START database-file KEY IS > data-tag
WHEN print-by-date
PERFORM start-at-last-date
SET read-backwards TO TRUE
END-EVALUATE
PERFORM FOREVER
*> The problem with statements instead of functions...
IF NOT read-backwards
READ database-file NEXT
AT END
EXIT PERFORM
END-READ
ELSE
READ database-file PREVIOUS
AT END
EXIT PERFORM
END-READ
END-IF
PERFORM show-record
DISPLAY SPACE
END-PERFORM
PERFORM close-database
.
start-at-last-date.
MOVE HIGH-VALUES TO date-added
START database-file KEY IS < date-added
.
close-database.
CLOSE database-file
.
show-record.
MOVE date-added TO edited-date
DISPLAY "Date added: " edited-date " Tag: " data-tag
DISPLAY "Title: " data-title
DISPLAY "Contents:"
DISPLAY " " FUNCTION TRIM(data-contents)
.
show-general-help.
DISPLAY "Help: Possible options are:"
DISPLAY " -a - Show all the entries (sorted by title)."
DISPLAY " -c - Create a new entry in the database. -c needs"
" further arguments in this format:"
DISPLAY ' "tag" "title" "content"'
DISPLAY " Max argument sizes (in characters): tag - 20, "
"title - 50, content - 200"
DISPLAY " The title must be unique and not be blank."
DISPLAY " -d - Show all the entries sorted by date added."
DISPLAY " -f - Finds and displays entry with the title "
"provided. The title should be specified as shown for "
"-c."
DISPLAY " -h - Show this help menu."
DISPLAY " -l - Show the latest entry."
DISPLAY " -r - Remove the entry with the title provided. "
"The title should be specified as shown for -c."
DISPLAY " -t - Show all the entries sorted by tag."
.</lang>
Sample session:
$ ./database -c "Reminder" "Bob's Birthday" "Buy birthday present for Bob." $ ./database -c "Wishlist" "Beethoven" "Beethoven's Ode to Joy" $ ./database -c "Reminder" "Add to Simple Database" "Add brainf*** example for Simple Database on Rosetta Code." ... $ ./database -f "Mozart" An entry with that title was not found. $ ./database -t Date added: 2013/08/13 Tag: Reminder Title: Bob's Birthday Contents: Buy birthday present for Bob. Date added: 2013/08/13 Tag: Reminder Title: Add to Simple Database Contents: Add brainf*** example for Simple Database on Rosetta Code. Date added: 2013/08/13 Tag: Wishlist Title: Beethoven Contents: Beethoven's Ode to Joy $ ./database -r "Beethoven" $ ./database -l Date added: 2013/08/13 Tag: Reminder Title: Add to Simple Database Contents: Add brainf*** example for Simple Database on Rosetta Code. $
Common Lisp
Tested with Common Lisp. (Save the code below as db.lisp)
<lang lisp>(defvar *db* nil)
(defvar *db-cat* (make-hash-table :test 'equal))
(defvar *db-file* "db.txt")
(defstruct item
"this is the unit of data stored/displayed in *db*" (title " ") (category "default") (date (progn (get-universal-time))))
(defun set-category(new-item)
(setf (gethash (item-category new-item) *db-cat*) 't))
(defun find-item-in-db (&optional category)
(if (null category)
(car *db*)
(find category *db* :key #'item-category :test #'string=)))
(defun scan-category ()
"scan categories from an existing database -- after reading it from disk" (dolist (itm *db*) (set-category itm)))
(defun pr-univ-time (utime)
(multiple-value-bind (second minute hour date month year day-of-week dst-p tz) (decode-universal-time utime) (declare (ignore day-of-week dst-p tz)) (format nil "~4,'0d-~2,'0d-~2,'0d ~2,'0d:~2,'0d:~2,'0d" year month date hour minute second)))
(defun pr (&optional (item (find-item-in-db)) (stream t))
"print an item" (when item (format stream "~a: (~a) (~a)~%"
(item-title item) (item-category item) (pr-univ-time (item-date item)))))
(defun pr-per-category ()
"print the latest item from each category" (loop for k being the hash-keys in *db-cat*
do (pr (find-item-in-db k))))
(defun pr-all ()
"print all the items, *db* is sorted by time." (dolist (itm *db*) (pr itm)))
(defun pr-all-categories (&optional (stream t))
(loop for k being the hash-keys in *db-cat*
do (format stream "(~a) " k)))
(defun insert-item (item)
"insert item into database in a time sorted list. okay for a small list, as per spec."
(let ((first-item (car *db*)) (new-itm item))
(set-category new-itm)
(push new-itm *db*)
(when (and first-item (>= (item-date new-itm) (item-date first-item)))
(setf *db* (sort *db* #'> :key #'item-date)))
*db*))
(defun read-db-from-file (&optional (file *db-file*))
(with-open-file (in file :if-does-not-exist nil)
(when in (with-standard-io-syntax (setf *db* (read in))) (scan-category))))
(defun save-db-to-file (&optional (file *db-file*))
(with-open-file (out file :direction :output :if-exists :supersede)
(with-standard-io-syntax (print *db* out))))
(defun del-db ()
(setf *db* nil) (save-db-to-file))
(defun del-item (itm)
(read-db-from-file) (setf *db* (remove itm *db* :key #'item-title :test #'string=)) (save-db-to-file))
(defun add-item-to-db (args)
(read-db-from-file) (insert-item (make-item :title (first args) :category (second args))) (save-db-to-file))
(defun help-menu ()
(format t "clisp db.lisp ~{~15T~a~^~% ~}"
'("delete <item-name> ------------------- delete an item" "delete-all --------------------------- delete the database"
"insert <item-name> <item-category> --- insert an item with its category"
"show --------------------------------- shows the latest inserted item" "show-categories ---------------------- show all categories" "show-all ----------------------------- show all items" "show-per-category -------------------- show the latest item per category")))
(defun db-cmd-run (args)
(cond ((and (> (length args) 1) (equal (first args) "delete"))
(del-item (second args))) ((equal (first args) "delete-all") (del-db)) ((and (> (length args) 2) (equal (first args) "insert")) (add-item-to-db (rest args))) ((equal (first args) "show") (read-db-from-file) (pr)) ((equal (first args) "show-categories") (read-db-from-file) (pr-all-categories))
((equal (first args) "show-all") (read-db-from-file) (pr-all))
((equal (first args) "show-per-category") (read-db-from-file) (pr-per-category))
(t (help-menu))))
(defun db-argv ()
(or #+clisp ext:*args* #+sbcl (cdr sb-ext:*posix-argv*) #+allegro (cdr (sys:command-line-arguments)) #+lispworks (cdr sys:*line-arguments-list*) nil))
(db-cmd-run (db-argv))</lang>
Help menu:
$ clisp db.lisp
clisp db.lisp delete <item-name> ------------------- delete an item
delete-all --------------------------- delete the database
insert <item-name> <item-category> --- insert an item with its category
show --------------------------------- shows the latest inserted item
show-categories ---------------------- show all categories
show-all ----------------------------- show all items
show-per-category -------------------- show the latest item per category
Here are a few steps to add a few titles, and their categories:
$ clisp db.lisp insert "title-vinyl-1" "vinyl" $ clisp db.lisp insert "title-cd-1" "cd" $ clisp db.lisp insert "title-dvd-1" "dvd" $ clisp db.lisp insert "title-tape-1" "tape" $ clisp db.lisp insert "title-tape-2" "tape"
Here is the very latest entry in the db:
$ clisp db.lisp show title-tape-2: (tape) (2017-04-04 20:19:06)
Here is a (sorted time wise) list of all the entries:
$ clisp db.lisp show-all title-tape-2: (tape) (2017-04-04 20:19:06) title-tape-1: (tape) (2017-04-04 20:19:00) title-dvd-1: (dvd) (2017-04-04 20:18:55) title-cd-1: (cd) (2017-04-04 20:18:48) title-vinyl-1: (vinyl) (2017-04-04 20:18:41)
Here is the latest entry for each category:
$ clisp db.lisp show-per-category title-vinyl-1: (vinyl) (2017-04-04 20:18:41) title-cd-1: (cd) (2017-04-04 20:18:48) title-dvd-1: (dvd) (2017-04-04 20:18:55) title-tape-2: (tape) (2017-04-04 20:19:06)
Here is the list of all categories:
$ clisp db.lisp show-categories (vinyl) (cd) (dvd) (tape)
To delete an entry:
$ clisp db.lisp delete "title-tape-2"
To delete all entries:
$ clisp db.lisp delete-all
D
<lang d>import std.stdio, std.algorithm, std.string, std.conv, std.array,
std.file, std.csv, std.datetime;
private {
immutable filename = "simdb.csv";
struct Item {
string name, date, category;
}
void addItem(in string[] item) {
if (item.length < 3)
return printUsage();
auto db = load();
const date = (cast(DateTime)Clock.currTime).toISOExtString;
const cat = (item.length == 4) ? item[3] : "none";
db ~= Item(item[2], date, cat);
store(db);
}
void printLatest(in string[] a) {
auto db = load();
if (db.empty)
return writeln("No entries in database.");
db.sort!q{ a.date > b.date };
if (a.length == 3) {
foreach (item; db)
if (item.category == a[2])
writefln("%s, %s, %s", item.tupleof);
} else {
writefln("%s, %s, %s", db[0].tupleof);
}
}
void printAll() {
auto db = load();
if (db.empty)
return writeln("No entries in database.");
db.sort!q{ a.date < b.date };
foreach (item; db)
writefln("%s, %s, %s", item.tupleof);
}
Item[] load() {
Item[] db;
if (filename.exists && filename.isFile) {
try {
const text = filename.readText;
if (!text.empty)
db = csvReader!Item(text).array;
} catch (CSVException e) {
writeln(e.msg);
}
}
return db;
}
void store(in Item[] db) {
auto f = File(filename, "w+");
foreach (item; db)
f.writefln("%s,%s,%s", item.tupleof);
}
void printUsage() {
writeln(
`Usage:
simdb cmd [categoryName]
add add item, followed by optional category latest print last added item(s), followed by optional category all print all
For instance: add "some item name" "some category name"`); }
}
void main(in string[] args) {
if (args.length < 2 || args.length > 4)
return printUsage();
switch (args[1].toLower) {
case "add": addItem(args); break;
case "latest": printLatest(args); break;
case "all": printAll(); break;
default: printUsage(); break;
}
}</lang>
- Output:
C:\>simdb add item1 cat1 C:\>simdb add item2 cat2 C:\>simdb add item3 cat3 C:\>simdb add item4 C:\>simdb add item5 C:\>simdb add item6 cat4 C:\>simdb add item7 cat4 C:\>simdb latest item7, 2014-06-04T16:02:01, cat4 C:\>simdb latest cat4 item7, 2014-06-04T16:02:01, cat4 item6, 2014-06-04T16:01:55, cat4 C:\>simdb all item1, 2014-06-04T16:01:26, cat1 item2, 2014-06-04T16:01:34, cat2 item3, 2014-06-04T16:01:41, cat3 item4, 2014-06-04T16:01:46, none item5, 2014-06-04T16:01:49, none item6, 2014-06-04T16:01:55, cat4 item7, 2014-06-04T16:02:01, cat4 C:\>simdb add Usage: simdb cmd [categoryname] add add item, followed by optional category latest print last added item(s), followed by optional category all print all For instance: add "some item name" "some category name"
File:
item1,2014-06-04T16:01:26,cat1 item2,2014-06-04T16:01:34,cat2 item3,2014-06-04T16:01:41,cat3 item4,2014-06-04T16:01:46,none item5,2014-06-04T16:01:49,none item6,2014-06-04T16:01:55,cat4 item7,2014-06-04T16:02:01,cat4
Erlang
<lang Erlang>
- ! /usr/bin/env escript
-compile({no_auto_import,[date/0]}).
main( ["add", Tag | Descriptions] ) -> add( date(), Tag, Descriptions ); main( ["add_date", Date, Tag | Descriptions] ) -> add( date_internal(string:tokens(Date, "-")), Tag, Descriptions ); main( ["print_latest"] ) -> print_latest( contents() ); main( ["print_latest_for_each"] ) -> print_latest_for_each( contents() ); main( ["print_all_date", Date] ) -> print_all_date( date_internal(string:tokens(Date, "-")), contents() ); main( _Error ) -> usage().
add( Date, Tag, Descriptions ) -> Contents = contents(), file:write_file( file(), io_lib:format("simple_database_v1.~n~p.~n", [[{Date, Tag, Descriptions} | Contents]]) ).
date() -> Template:Date, Time = calendar:local_time(), Date.
date_external( {Year, Month, Day} ) -> string:join( [erlang:integer_to_list(Year), erlang:integer_to_list(Month), erlang:integer_to_list(Day)], "-" ); date_external( _Error ) -> usage().
date_internal( [Year, Month, Day] ) -> {erlang:list_to_integer(Year), erlang:list_to_integer(Month), erlang:list_to_integer(Day)}; date_internal( _Error ) -> usage().
file() -> "simple_database_contents".
contents() -> contents( file:consult(file()) ).
contents( {ok, [simple_database_v1, Contents]} ) -> Contents; contents( {error, Error} ) when is_atom(Error) -> []; contents( {error, _Error} ) -> io:fwrite( "Error: ~p corrupt. Starting from scratch~n", [file()] ), [].
print_all_date( _Date, [] ) -> ok; print_all_date( Date, Contents ) -> [print_latest([{D, Tag, Descriptions}]) || {D, Tag, Descriptions} <- Contents, D =:= Date].
print_latest( [] ) -> ok; print_latest( [{Date, Tag, Descriptions} | _T] ) -> io:fwrite( "~s~n", [string:join( [date_external(Date), Tag | Descriptions], " ")] ).
print_latest_for_each( [] ) -> ok; print_latest_for_each( Contents ) -> Tags = lists:usort( [Tag || {_Date, Tag, _Descriptions} <- Contents] ), [print_latest([lists:keyfind(X, 2, Contents)]) || X <- Tags].
usage() -> io:fwrite( "Usage: ~p [add | add_date <date>] tag description ...~n", [escript:script_name()] ), io:fwrite( "Or: ~p [print_latest | print_latest_for_each | print_all_date <date>]~n", [escript:script_name()] ), io:fwrite( "Date format is YYYY-MM-DD~n" ), io:fwrite( "Data stored in ~p~n", [file()] ), init:stop(). </lang> Command line session started with these file contents as database:
simple_database_v1.
[{{2013,9,16},"comic",["hobbe"]},
{{2013,9,16},"comic",["gustaf"]}].
Command line session:
./simple_database add num 1 2 3 ./simple_database add_date 1991-01-01 num 999 888 ./simple_database print_latest 1991-1-1 num 999 888 ./simple_database print_latest_for_each 2013-9-16 comic hobbe 1991-1-1 num 999 888 ./simple_database print_all_date 2013-09-16 2013-9-16 num 1 2 3 2013-9-16 comic hobbe 2013-9-16 comic gustaf
Forth
Simple in-memory database. Load/dump database from/to a file.
Example file 'test.sdb':
+: betty 1974.03.03;coworker;reading; +: geea 1980.01.01;friend;sketch writer; +: tom 1991.03.07;family member;reading; +: alice 1987.09.01;coworker;classical music; +: gammaQ3.14 3045.09.09;friend;watch movies, star walking;
Example usage:
$ gforth sdb.fs help [ -erased help message- ] load test.sdb ok .keys gammaQ3.14 alice tom geea betty ok betty .record betty 1974.03.03;coworker;reading; ok newline geea .record geea 1980.01.01;friend;sketch writer; ok +: theea 1979.04.05;coworker;astronomy; ok newline .bydate gammaQ3.14 3045.09.09;friend;watch movies, star walking; tom 1991.03.07;family member;reading; alice 1987.09.01;coworker;classical music; geea 1980.01.01;friend;sketch writer; theea 1979.04.05;coworker;astronomy; betty 1974.03.03;coworker;reading; dump t2.sdb ok bye $ $ cat t2.sdb +: betty 1974.03.03;coworker;reading; +: geea 1980.01.01;friend;sketch writer; +: tom 1991.03.07;family member;reading; +: alice 1987.09.01;coworker;classical music; +: gammaQ3.14 3045.09.09;friend;watch movies, star walking; +: theea 1979.04.05;coworker;astronomy; $
Code: <lang forth>\ sdb.fs Simple database. Gforth 0.7.0 specific ' noop is bootmessage
wordlist constant USER: \ USER functions wordlist constant SDB \ DB keys wordlist constant FIELDS \ DB fields
- -SDB?EXIT ( -- ; Continue if `SDB' non-empty )
SDB cell+ @ 0= IF rdrop exit THEN ;
\ MACROS
- |comp| ( MACRO: | code to be compiled | )
char parse evaluate ; immediate
- LIST ( node -- ) ]] BEGIN @ dup WHILE >R [[ ; immediate
- LOOP-LIST ( -- ) ]] R> REPEAT drop [[ ; immediate
- UNLIST ( -- ) POSTPONE rdrop ; immediate
\ Helper words
- .; [char] ; emit ;
- !+ dup cell+ -rot ! ;
- ($+) ( cas us cad ud -- cad us+ud ; append source string to destination )
swap >R 2dup + R> swap >R tuck + swap >R swap move R> R> ;
\ --- Working Record Fields current @ FIELDS current ! 2variable person 2variable birthday 2variable relationship 2variable hobby current ! FIELDS >order
\ --- Ring list
- new-node ( -- node ; root of circular list )
here dup , ;
- do-link ( node new-node -- ; do link after current node )
over @ over ! swap ! ;
- empty-ring? ( node -- f ) dup @ = ;
- RING ( node -- ) ]] dup BEGIN @ 2dup <> WHILE 2>R [[ ; immediate
- LOOP-RING ( -- ) ]] 2R> REPEAT 2drop [[ ; immediate
- UNRING ( -- ) postpone 2RDROP ; immediate
- noname
s" " person 2! s" 9999.01.01" birthday 2! s" " relationship 2! s" " hobby 2! ; new-node swap , CONSTANT OLD
\ --- Insertion into ring
- node>xt ( node -- xt ) cell+ @ ;
- bday@ ( node -- ca u ) node>xt execute birthday 2@ ;
- datecmp ( node node -- -1|0|1 ) bday@ rot bday@ compare ;
- search-by-date ( new-node node -- node' ; Linear search by birth date )
dup RING ( new-node node ) over I datecmp 0< IF nip UNRING exit ELSE drop I THEN LOOP-RING nip ;
- insert-ordered ( new-node -- )
OLD dup empty-ring? 0= IF over swap search-by-date THEN swap do-link ;
\ --- Field compiling
- fld: [char] ; parse postpone sliteral ; immediate
- _sdb-walk ( MACRO: | xt[--] -- | )
]] -SDB?EXIT here dup SDB cell+ LIST I name>int swap !+ LOOP-LIST 1 cells literal - DO I @ |comp| -1 cells literal +LOOP [[ ; immediate
2variable category
- msg_nocategory ( -- )
." No such category!" cr ;
\ --- USER definitions user: >order current @ USER: current !
- bye bye ;
- .s .s ;
- newline cr ;
- godb SDB >order ;
- .keys SDB wordlist-words ;
- .person person 2@ type ;
- .birthday birthday 2@ type ;
- .relationship relationship 2@ type ;
- .hobby hobby 2@ type ;
- .record .person 1 spaces .birthday .; .relationship .; .hobby .; ;
- .last SDB cell+ @ dup
IF name>int execute .record ELSE drop THEN ;
- .lastbycategory ( "field-name" -- )
here 0 category 2! parse-name FIELDS search-wordlist IF sdb cell+ LIST ( xt ) I name>int execute dup execute 2@ category 2@ 2swap search nip nip 0= IF .record cr dup execute 2@ category 2@ ($+) category 2! THEN LOOP-LIST drop ELSE ['] msg_nocategory stderr OUTFILE-EXECUTE THEN ;
- .bydate ( -- )
OLD RING I node>xt execute .record cr LOOP-RING ;
- .sdb _sdb-walk | execute .record cr | ;
- sdb-dump _sdb-walk | execute ." +: " .record cr | ;
- dump ( "db-file" -- )
parse-name w/o CREATE-FILE throw dup ['] sdb-dump swap OUTFILE-EXECUTE CLOSE-FILE throw ;
- load ( "db-file" -- ) include ;
- +: ( "person birth-day;relationship;hobby; -- )
new-node dup cell+ >R 0 , \ post `xt' current @ SDB current ! \ compile into `sdb' wordlist : latestxt dup R> ! \ fix-up `xt' ]] literal >name name>string person 2! fld: birthday 2! fld: relationship 2! fld: hobby 2! ; [[ current ! insert-ordered ;
- HELP cr
cr ." KEYWORDS: " USER: wordlist-words cr ." ---" cr ." Prefix `.' means print" cr ." To add a record, type: +: name yyyy.mm.dd;relationship;hobby;" cr cr ; current ! SEAL godb</lang>
Go
<lang go>package main
import (
"encoding/json" "fmt" "io" "os" "sort" "strings" "time" "unicode"
)
// Database record format. Time stamp and name are required. // Tags and notes are optional. type Item struct {
Stamp time.Time Name string Tags []string `json:",omitempty"` Notes string `json:",omitempty"`
}
// Item implements stringer interface func (i *Item) String() string {
s := i.Stamp.Format(time.ANSIC) + "\n Name: " + i.Name
if len(i.Tags) > 0 {
s = fmt.Sprintf("%s\n Tags: %v", s, i.Tags)
}
if i.Notes > "" {
s += "\n Notes: " + i.Notes
}
return s
}
// collection of Items type db []*Item
// db implements sort.Interface func (d db) Len() int { return len(d) } func (d db) Swap(i, j int) { d[i], d[j] = d[j], d[i] } func (d db) Less(i, j int) bool { return d[i].Stamp.Before(d[j].Stamp) }
// hard coded database file name const fn = "sdb.json"
func main() {
if len(os.Args) == 1 {
latest()
return
}
switch os.Args[1] {
case "add":
add()
case "latest":
latest()
case "tags":
tags()
case "all":
all()
case "help":
help()
default:
usage("unrecognized command")
}
}
func usage(err string) {
if err > "" {
fmt.Println(err)
}
fmt.Println(`usage: sdb [command] [data]
where command is one of add, latest, tags, all, or help.`)
}
func help() {
usage("")
fmt.Println(`
Commands must be in lower case. If no command is specified, the default command is latest.
Latest prints the latest item. All prints all items in chronological order. Tags prints the lastest item for each tag. Help prints this message.
Add adds data as a new record. The format is,
name [tags] [notes]
Name is the name of the item and is required for the add command.
Tags are optional. A tag is a single word. A single tag can be specified without enclosing brackets. Multiple tags can be specified by enclosing them in square brackets.
Text remaining after tags is taken as notes. Notes do not have to be enclosed in quotes or brackets. The brackets above are only showing that notes are optional.
Quotes may be useful however--as recognized by your operating system shell or command line--to allow entry of arbitrary text. In particular, quotes or escape characters may be needed to prevent the shell from trying to interpret brackets or other special characters.
Examples: sdb add Bookends // no tags, no notes sdb add Bookends rock my favorite // tag: rock, notes: my favorite sdb add Bookends [rock folk] // two tags sdb add Bookends [] "Simon & Garfunkel" // notes, no tags sdb add "Simon&Garfunkel [artist]" // name: Simon&Garfunkel, tag: artist
As shown in the last example, if you use features of your shell to pass all data as a single string, the item name and tags will still be identified by separating whitespace.
The database is stored in JSON format in the file "sdb.json" `) }
// load data for read only purposes. func load() (db, bool) {
d, f, ok := open()
if ok {
f.Close()
if len(d) == 0 {
fmt.Println("no items")
ok = false
}
}
return d, ok
}
// open database, leave open func open() (d db, f *os.File, ok bool) {
var err error
f, err = os.OpenFile(fn, os.O_RDWR|os.O_CREATE, 0666)
if err != nil {
fmt.Println("cant open??")
fmt.Println(err)
return
}
jd := json.NewDecoder(f)
err = jd.Decode(&d)
// EOF just means file was empty. That's okay with us.
if err != nil && err != io.EOF {
fmt.Println(err)
f.Close()
return
}
ok = true
return
}
// handle latest command func latest() {
d, ok := load()
if !ok {
return
}
sort.Sort(d)
fmt.Println(d[len(d)-1])
}
// handle all command func all() {
d, ok := load()
if !ok {
return
}
sort.Sort(d)
for _, i := range d {
fmt.Println("-----------------------------------")
fmt.Println(i)
}
fmt.Println("-----------------------------------")
}
// handle tags command func tags() {
d, ok := load()
if !ok {
return
}
// we have to traverse the entire list to collect tags so there
// is no point in sorting at this point.
// collect set of unique tags associated with latest item for each
latest := make(map[string]*Item)
for _, item := range d {
for _, tag := range item.Tags {
li, ok := latest[tag]
if !ok || item.Stamp.After(li.Stamp) {
latest[tag] = item
}
}
}
// invert to set of unique items, associated with subset of tags
// for which the item is the latest.
type itemTags struct {
item *Item
tags []string
}
inv := make(map[*Item][]string)
for tag, item := range latest {
inv[item] = append(inv[item], tag)
}
// now we sort just the items we will output
li := make(db, len(inv))
i := 0
for item := range inv {
li[i] = item
i++
}
sort.Sort(li)
// finally ready to print
for _, item := range li {
tags := inv[item]
fmt.Println("-----------------------------------")
fmt.Println("Latest item with tags", tags)
fmt.Println(item)
}
fmt.Println("-----------------------------------")
}
// handle add command func add() {
if len(os.Args) < 3 {
usage("add command requires data")
return
} else if len(os.Args) == 3 {
add1()
} else {
add4()
}
}
// add command with one data string. look for ws as separators. func add1() {
data := strings.TrimLeftFunc(os.Args[2], unicode.IsSpace)
if data == "" {
// data must have at least some non-whitespace
usage("invalid name")
return
}
sep := strings.IndexFunc(data, unicode.IsSpace)
if sep < 0 {
// data consists only of a name
addItem(data, nil, "")
return
}
name := data[:sep]
data = strings.TrimLeftFunc(data[sep:], unicode.IsSpace)
if data == "" {
// nevermind trailing ws, it's still only a name
addItem(name, nil, "")
return
}
if data[0] == '[' {
sep = strings.Index(data, "]")
if sep < 0 {
// close bracketed list for the user. no notes.
addItem(name, strings.Fields(data[1:]), "")
} else {
// brackets make things easy
addItem(name, strings.Fields(data[1:sep]),
strings.TrimLeftFunc(data[sep+1:], unicode.IsSpace))
}
return
}
sep = strings.IndexFunc(data, unicode.IsSpace)
if sep < 0 {
// remaining word is a tag
addItem(name, []string{data}, "")
} else {
// there's a tag and some data
addItem(name, []string{data[:sep]},
strings.TrimLeftFunc(data[sep+1:], unicode.IsSpace))
}
}
// add command with multiple strings remaining on command line func add4() {
name := os.Args[2]
tag1 := os.Args[3]
if tag1[0] != '[' {
// no brackets makes things easy
addItem(name, []string{tag1}, strings.Join(os.Args[4:], " "))
return
}
if tag1[len(tag1)-1] == ']' {
// tags all in one os.Arg is easy too
addItem(name, strings.Fields(tag1[1:len(tag1)-1]),
strings.Join(os.Args[4:], " "))
return
}
// start a list for tags
var tags []string
if tag1 > "[" {
tags = []string{tag1[1:]}
}
for x, tag := range os.Args[4:] {
if tag[len(tag)-1] != ']' {
tags = append(tags, tag)
} else {
// found end of tag list
if tag > "]" {
tags = append(tags, tag[:len(tag)-1])
}
addItem(name, tags, strings.Join(os.Args[5+x:], " "))
return
}
}
// close bracketed list for the user. no notes.
addItem(name, tags, "")
}
// complete the add command func addItem(name string, tags []string, notes string) {
db, f, ok := open()
if !ok {
return
}
defer f.Close()
// add the item and format JSON
db = append(db, &Item{time.Now(), name, tags, notes})
sort.Sort(db)
js, err := json.MarshalIndent(db, "", " ")
if err != nil {
fmt.Println(err)
return
}
// time to overwrite the file
if _, err = f.Seek(0, 0); err != nil {
fmt.Println(err)
return
}
f.Truncate(0)
if _, err = f.Write(js); err != nil {
fmt.Println(err)
}
}</lang>
Haskell
The database is a list of type Item stored in a StateT monad transformer that allows for IO actions to be perfomed with it (StateT [Item] IO a). All IO actions occurring inside the StateT monad (handling command line arguments and printing items) must be lifted. The database is written to disk using "show" and read back using "read". Therefore, Item is declared as an instance of both Show and Read classes. An item in the database file looks like the following: Item {description = "La traviata", category = ["Classical"], date = Date 2012 10 19, optional = ["Giuseppe Verdi","1853"]}
<lang Haskell>import Control.Monad.State import Data.List (sortBy, nub) import System.Environment (getArgs, getProgName) import System.Directory (doesFileExist) import System.IO (openFile, hGetContents, hClose, IOMode(..),
Handle, hPutStrLn)
-- for storing dates data Date = Date Integer Int Int deriving (Show, Read, Eq, Ord)
-- for storing database items data Item = Item {description :: String
,category :: [String]
,date :: Date
,optional :: [String]}
deriving (Show, Read)
-- a state monad transformer which wraps IO actions. -- the database (state) is passed implicitly between functions. type ItemList a = StateT [Item] IO a
-- add an item to the database addItem :: Item -> ItemList () addItem i = modify (++ [i])
-- get the newest of a list of items latest :: [Item] -> [Item] latest [] = [] latest [x]= [x] latest xs = take 1 $ sortBy newer xs
-- compare two items to see which one is newer newer :: Item -> Item -> Ordering newer a b = compare (date b) (date a)
-- list all different categories (no duplicates) categories :: ItemList [String] categories = liftM (nub . concatMap category) get
-- list only the items with the given category tag filterByCategory :: String -> ItemList [Item] filterByCategory c = liftM (filter (\i -> c `elem` category i)) get
-- get the newest of all items lastOfAll :: ItemList [Item] lastOfAll = liftM latest get
-- get the newest item in each category latestByCategory :: ItemList [Item] latestByCategory = do
cats <- categories filt <- mapM filterByCategory cats return $ concatMap latest filt
-- sort all items chronologically, newest first sortByDate :: ItemList [Item] sortByDate = liftM (sortBy newer) get
toScreen :: Item -> IO () toScreen (Item desc cats (Date y m d) opt) = putStrLn $
"Description:\t" ++ desc ++ "\nCategories:\t" ++ show cats ++ "\nDate:\t\t" ++ show y ++ "-" ++ show m ++ "-" ++ show d ++ "\nOther info:\t" ++ show opt
-- command line argument handling -- if the user called the program with the option "add", the -- new item is returned to main so that it can be saved to disk. -- the argument "opt" is a list. arguments :: ItemList [Item] arguments = do
args <- liftIO getArgs
case args of
("add":desc:cat:year:month:day:opt) -> do
let newItem = parseItem args
addItem newItem
return [newItem]
("latest":[]) -> do
item <- lastOfAll
lift $ mapM_ toScreen item
return []
("category":[]) -> do
items <- latestByCategory
lift $ mapM_ toScreen items
return []
("all":[]) -> do
sorted <- sortByDate
lift $ mapM_ toScreen sorted
return []
_ -> do
lift usage
return []
parseItem :: [String] -> Item parseItem (_:desc:cat:year:month:day:opt) =
Item {description = desc, category = words cat,
date = Date (read year) (read month) (read day),
optional = opt}
usage :: IO () usage = do
progName <- getProgName
putStrLn $ "Usage: " ++ progName ++ " add|all|category|latest \
\OPTIONS\n\nadd \"description\" \"category1 category2\"... \
\year month day [\"note1\" \"note2\"...]\n\tAdds a new record \
\to the database.\n\nall\n\tPrints all items in chronological \
\order.\n\ncategory\n\tPrints the latest item for each category.\
\\n\nlatest\n\tPrints the latest item."
-- the program creates, reads and writes to a file in the current directory main :: IO () main = do
progName <- getProgName
let fileName = progName ++ ".db"
e <- doesFileExist fileName
if e
then do
hr <- openFile fileName ReadMode
f <- hGetContents hr
v <- evalStateT arguments (map read $ lines f)
hClose hr -- must be called after working with contents!
hw <- openFile fileName AppendMode
mapM_ (hPutStrLn hw . show) v
hClose hw
else do
v <- evalStateT arguments []
hw <- openFile fileName WriteMode
mapM_ (hPutStrLn hw . show) v
hClose hw
</lang>
J
J comes with a sql database, jdb. Jdb's columns are memory mapped files with header information. These won't meet the human readable data file requirement. Hence, this program:
<lang j>HELP=: 0 :0 Commands:
DBNAME add DATA DBNAME display the latest entry DBNAME display the latest entry where CATEGORY contains WORD DBNAME display all entries DBNAME display all entries order by CATEGORY
1) The first add with new DBNAME assign category names. 2) lower case arguments verbatim. 3) UPPER CASE: substitute your values.
Examples, having saved this program as a file named s : $ jconsole s simple.db display all entries $ jconsole s simple.db add "first field" "2nd field" )
Q=: ' NB. quote character time=: 6!:0@:('YYYY-MM-DD:hh:mm:ss.sss'"_)
embed=: >@:{.@:[ , ] , >@:{:@:[ assert '(x+y)' -: '()' embed 'x+y'
Duplicate=: 1 :'#~ m&= + 1 #~ #' assert 0 1 2 3 3 4 -: 3 Duplicate i.5
prepare=: LF ,~ [: }:@:; (Q;Q,';')&embed@:(Q Duplicate)&.>@:(;~ time) assert (-: }.@:".@:}:@:prepare) 'boxed';;'list';'of';strings
categorize=: dyad define i=. x i. y if. (1 (~: #) i) +. i (= #) x do.
smoutput 'choose 1 of' smoutput x exit 1
end. {. i NB. "index of" frame has rank 1. ) assert 0 -: 'abc' categorize 'a'
loadsdb=: (<'time') (<0 0)} ".;._2@:(1!:1)
Dispatch=: conjunction define help
commands=. y command=. {. commands x (u`help@.(command(i.~ ;:)n)) }.commands )
NB. the long fork in show groups (": #~ (1 1 embed (1j1 }:@:# (1 #~ #)))) show=: smoutput@:(": #~ 1 1 embed 1j1 }:@:# 1 #~ #)
in=: +./@:E. assert 'the' in'quick brown fox jumps over the lazy dog' assert 'the'-.@:in'QUICK BROWN FOX JUMPS OVER THE LAZY DOG'
where=: dyad define 'category contains word'=. 3 {. y if. 'contains' -.@:-: contains do.
help exit 1
end. i=. x ({.@:[ categorize <@:]) category j=. {: I. ; word&in&.> i {"1 x if. 0 (= #) j do.
smoutput 'no matches'
else.
x (show@:{~ 0&,) j
end. )
entry=: 4 : 0 if. a: = y do.
show@:({. ,: {:) x
else.
x `where Dispatch'where' y
end. )
latest=: `entry Dispatch'entry' the=: `latest Dispatch'latest'
by=: 4 : 0 i=. x (categorize~ {.)~ y show ({. , (/: i&{"1)@:}.) x )
order=: `by Dispatch'by'
entries=: 4 : 0 if. a: = y do.
show x
else.
x `order Dispatch'order' y
end. )
all=: `entries Dispatch'entries'
help=: smoutput@:(HELP"_) add=: 1!:3~ prepare NB. minimal---no error tests display=: (the`all Dispatch'the all'~ loadsdb)~ NB. load the simple db for some sort of display
({. add`display Dispatch'add display' }.)@:(2&}.)ARGV
exit 0 </lang> Assume the j code is stored in file s . These bash commands, stored in file input , create a database using add . <lang sh>D='jconsole s dataflow'
$D add name expression algebraic rank valence example explanation $D add insert 'f/ y' 'insert f within y' infinite dyad 'sum=: +/' 'continued_fraction=:+`%/' $D add fork '(f g h)y' 'g(f(y),h(y))' infinite monad 'average=: +/ % #' 'sum divided by tally' $D add hook '(f g)y' 'f(y,g(y))' infinite monad '(/: 2&{"1)table' 'sort by third column' $D add hook 'x(f g)y' 'f(x,g(y))' infinite dyad 'display verb in s' 'a reflexive dyadic hook' $D add fork 'x(f g h)y' 'g(f(x,y),h(x,y))' infinite dyad '2j1(+ * -)9 12' 'product of sum and difference' $D add reflexive 'f~ y' 'f(y,y)' infinite monad '^~y' 'y raised to the power of y' $D add passive 'x f~ y' 'f(y,x)' 'ranks of f' dyad '(%~ i.@:>:) 8x' '8 intervals from 0 to 1' $D add atop 'f@g y' 'f(g(y))' 'rank of g' monad '*:@(+/)' 'square the sum' $D add atop 'x f@g y' 'f(g(x,y))' 'rank of g' dyad '>@{.' '(lisp) open the car' $D add 'many more!' </lang> Now we look up data from the bash command line. <lang sh> $ . input # source the input $ echo $D jconsole s dataflow $ $D display the latest entry ┌───────────────────────┬──────────┬──────────┬─────────┬────┬───────┬───────┬───────────┐ │time │name │expression│algebraic│rank│valence│example│explanation│ │2012-02-07:20:36:54.749│many more!│ │ │ │ │ │ │ └───────────────────────┴──────────┴──────────┴─────────┴────┴───────┴───────┴───────────┘ $ $D display the latest entry where 'part of speech' contains verb choose 1 of ┌────┬────┬──────────┬─────────┬────┬───────┬───────┬───────────┐ │time│name│expression│algebraic│rank│valence│example│explanation│ └────┴────┴──────────┴─────────┴────┴───────┴───────┴───────────┘ $ $D display the latest entry where example contains average ┌───────────────────────┬────┬──────────┬────────────┬────────┬───────┬────────────────┬────────────────────┐ │time │name│expression│algebraic │rank │valence│example │explanation │ │2012-02-07:20:36:54.564│fork│(f g h)y │g(f(y),h(y))│infinite│monad │average=: +/ % #│sum divided by tally│ └───────────────────────┴────┴──────────┴────────────┴────────┴───────┴────────────────┴────────────────────┘ $ $D display all entries ordre by valence # oops! transposition typo. Commands:
DBNAME add DATA DBNAME display the latest entry DBNAME display the latest entry where CATEGORY contains WORD DBNAME display all entries DBNAME display all entries order by CATEGORY
1) The first add with new DBNAME assign category names. 2) lower case arguments verbatim. 3) UPPER CASE: substitute your values.
Examples, having saved this program as a file named s : $ jconsole s simple.db display all entries $ jconsole s simple.db add "first field" "2nd field"
$ $D display all entries order by valence ┌───────────────────────┬──────────┬──────────┬─────────────────┬──────────┬───────┬─────────────────┬─────────────────────────────┐ │time │name │expression│algebraic │rank │valence│example │explanation │ │2012-02-08:23:45:06.539│many more!│ │ │ │ │ │ │ │2012-02-08:23:45:06.329│insert │f/ y │insert f within y│infinite │dyad │sum=: +/ │continued_fraction=:+`%/ │ │2012-02-08:23:45:06.400│hook │x(f g)y │f(x,g(y)) │infinite │dyad │display verb in s│a reflexive dyadic hook │ │2012-02-08:23:45:06.426│fork │x(f g h)y │g(f(x,y),h(x,y)) │infinite │dyad │2j1(+ * -)9 12 │product of sum and difference│ │2012-02-08:23:45:06.471│passive │x f~ y │f(y,x) │ranks of f│dyad │(%~ i.@:>:) 8x │8 intervals from 0 to 1 │ │2012-02-08:23:45:06.515│atop │x f@g y │f(g(x,y)) │rank of g │dyad │>@{. │(lisp) open the car │ │2012-02-08:23:45:06.353│fork │(f g h)y │g(f(y),h(y)) │infinite │monad │average=: +/ % # │sum divided by tally │ │2012-02-08:23:45:06.376│hook │(f g)y │f(y,g(y)) │infinite │monad │(/: 2&{"1)table │sort by third column │ │2012-02-08:23:45:06.448│reflexive │f~ y │f(y,y) │infinite │monad │^~y │y raised to the power of y │ │2012-02-08:23:45:06.493│atop │f@g y │f(g(y)) │rank of g │monad │*:@(+/) │square the sum │ └───────────────────────┴──────────┴──────────┴─────────────────┴──────────┴───────┴─────────────────┴─────────────────────────────┘ $ $D display all entries ┌───────────────────────┬──────────┬──────────┬─────────────────┬──────────┬───────┬─────────────────┬─────────────────────────────┐ │time │name │expression│algebraic │rank │valence│example │explanation │ │2012-02-08:23:45:06.329│insert │f/ y │insert f within y│infinite │dyad │sum=: +/ │continued_fraction=:+`%/ │ │2012-02-08:23:45:06.353│fork │(f g h)y │g(f(y),h(y)) │infinite │monad │average=: +/ % # │sum divided by tally │ │2012-02-08:23:45:06.376│hook │(f g)y │f(y,g(y)) │infinite │monad │(/: 2&{"1)table │sort by third column │ │2012-02-08:23:45:06.400│hook │x(f g)y │f(x,g(y)) │infinite │dyad │display verb in s│a reflexive dyadic hook │ │2012-02-08:23:45:06.426│fork │x(f g h)y │g(f(x,y),h(x,y)) │infinite │dyad │2j1(+ * -)9 12 │product of sum and difference│ │2012-02-08:23:45:06.448│reflexive │f~ y │f(y,y) │infinite │monad │^~y │y raised to the power of y │ │2012-02-08:23:45:06.471│passive │x f~ y │f(y,x) │ranks of f│dyad │(%~ i.@:>:) 8x │8 intervals from 0 to 1 │ │2012-02-08:23:45:06.493│atop │f@g y │f(g(y)) │rank of g │monad │*:@(+/) │square the sum │ │2012-02-08:23:45:06.515│atop │x f@g y │f(g(x,y)) │rank of g │dyad │>@{. │(lisp) open the car │ │2012-02-08:23:45:06.539│many more!│ │ │ │ │ │ │ └───────────────────────┴──────────┴──────────┴─────────────────┴──────────┴───────┴─────────────────┴─────────────────────────────┘ $ cat dataflow '2012-02-08:23:45:06.304';'name';'expression';'algebraic';'rank';'valence';'example';'explanation' '2012-02-08:23:45:06.329';'insert';'f/ y';'insert f within y';'infinite';'dyad';'sum=: +/';'continued_fraction=:+`%/' '2012-02-08:23:45:06.353';'fork';'(f g h)y';'g(f(y),h(y))';'infinite';'monad';'average=: +/ % #';'sum divided by tally' '2012-02-08:23:45:06.376';'hook';'(f g)y';'f(y,g(y))';'infinite';'monad';'(/: 2&{"1)table';'sort by third column' '2012-02-08:23:45:06.400';'hook';'x(f g)y';'f(x,g(y))';'infinite';'dyad';'display verb in s';'a reflexive dyadic hook' '2012-02-08:23:45:06.426';'fork';'x(f g h)y';'g(f(x,y),h(x,y))';'infinite';'dyad';'2j1(+ * -)9 12';'product of sum and difference' '2012-02-08:23:45:06.448';'reflexive';'f~ y';'f(y,y)';'infinite';'monad';'^~y';'y raised to the power of y' '2012-02-08:23:45:06.471';'passive';'x f~ y';'f(y,x)';'ranks of f';'dyad';'(%~ i.@:>:) 8x';'8 intervals from 0 to 1' '2012-02-08:23:45:06.493';'atop';'f@g y';'f(g(y))';'rank of g';'monad';'*:@(+/)';'square the sum' '2012-02-08:23:45:06.515';'atop';'x f@g y';'f(g(x,y))';'rank of g';'dyad';'>@{.';'(lisp) open the car' '2012-02-08:23:45:06.539';'many more!' $ </lang>
Java
<lang java>import java.io.*; import java.text.*; import java.util.*;
public class SimpleDatabase {
final static String filename = "simdb.csv";
public static void main(String[] args) {
if (args.length < 1 || args.length > 3) {
printUsage();
return;
}
switch (args[0].toLowerCase()) {
case "add":
addItem(args);
break;
case "latest":
printLatest(args);
break;
case "all":
printAll();
break;
default:
printUsage();
break;
}
}
private static class Item implements Comparable<Item>{
final String name;
final String date;
final String category;
Item(String n, String d, String c) {
name = n;
date = d;
category = c;
}
@Override
public int compareTo(Item item){
return date.compareTo(item.date);
}
@Override
public String toString() {
return String.format("%s,%s,%s%n", name, date, category);
}
}
private static void addItem(String[] input) {
if (input.length < 2) {
printUsage();
return;
}
List<Item> db = load();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String date = sdf.format(new Date());
String cat = (input.length == 3) ? input[2] : "none";
db.add(new Item(input[1], date, cat));
store(db);
}
private static void printLatest(String[] a) {
List<Item> db = load();
if (db.isEmpty()) {
System.out.println("No entries in database.");
return;
}
Collections.sort(db);
if (a.length == 2) {
for (Item item : db)
if (item.category.equals(a[1]))
System.out.println(item);
} else {
System.out.println(db.get(0));
}
}
private static void printAll() {
List<Item> db = load();
if (db.isEmpty()) {
System.out.println("No entries in database.");
return;
}
Collections.sort(db);
for (Item item : db)
System.out.println(item);
}
private static List<Item> load() {
List<Item> db = new ArrayList<>();
try (Scanner sc = new Scanner(new File(filename))) {
while (sc.hasNext()) {
String[] item = sc.nextLine().split(",");
db.add(new Item(item[0], item[1], item[2]));
}
} catch (IOException e) {
System.out.println(e);
}
return db;
}
private static void store(List<Item> db) {
try (FileWriter fw = new FileWriter(filename)) {
for (Item item : db)
fw.write(item.toString());
} catch (IOException e) {
System.out.println(e);
}
}
private static void printUsage() {
System.out.println("Usage:");
System.out.println(" simdb cmd [categoryName]");
System.out.println(" add add item, followed by optional category");
System.out.println(" latest print last added item(s), followed by "
+ "optional category");
System.out.println(" all print all");
System.out.println(" For instance: add \"some item name\" "
+ "\"some category name\"");
}
}</lang>
Output:
C:\temp>java -jar SimpleDatabase.jar add item1 C:\temp>java -jar SimpleDatabase.jar add item2 C:\temp>java -jar SimpleDatabase.jar add item3 cat3 C:\temp>java -jar SimpleDatabase.jar add item4 cat3 C:\temp>java -jar SimpleDatabase.jar add item5 cat3 C:\temp>java -jar SimpleDatabase.jar latest item1,2014-06-03 19:30:05,none C:\temp>java -jar SimpleDatabase.jar latest cat3 item3,2014-06-03 19:30:14,cat3 item4,2014-06-03 19:30:20,cat3 item5,2014-06-03 19:30:23,cat3 C:\temp>java -jar SimpleDatabase.jar all item1,2014-06-03 19:30:05,none item2,2014-06-03 19:30:08,none item3,2014-06-03 19:30:14,cat3 item4,2014-06-03 19:30:20,cat3 item5,2014-06-03 19:30:23,cat3
Perl
<lang Perl>#!/usr/bin/perl use warnings; use strict; use feature qw{ say };
use JSON::PP; use Time::Piece;
use constant {
NAME => 0, CATEGORY => 1, DATE => 2, DB => 'simple-db',
};
my $operation = shift // "";
my %dispatch = (
n => \&add_new, l => \&print_latest, L => \&print_latest_for_categories, a => \&print_all,
);
if ($dispatch{$operation}) {
$dispatch{$operation}->(@ARGV);
} else {
die "Invalid option. Use one of n, l, L, a.\n"
}
sub add_new {
my ($name, $category, $date) = @_;
my $db = eval { load() } || {};
if (defined $date) {
eval { 'Time::Piece'->strptime($date, '%Y-%m-%d'); 1 }
or die "Invalid date format: YYYY-MM-DD.\n";
} else {
$date //= localtime->ymd;
}
my @ids = keys %{ $db->{by_id} };
my $max_id = max(num => @ids) || 0;
$db->{by_id}{ ++$max_id } = [ $name, $category, $date ];
save($db);
}
sub print_latest {
build_indexes( my $db = load(), 0, 1 ); _print_latest($db);
}
sub _print_latest {
my ($db, $category) = @_;
my @dates = keys %{ $db->{by_date} };
@dates = grep {
grep $db->{by_id}{$_}[CATEGORY] eq $category,
@{ $db->{by_date}{$_} };
} @dates if defined $category;
my $last_date = max(str => @dates);
say for map $db->{by_id}{$_}[NAME],
grep ! defined $category
|| $db->{by_id}{$_}[CATEGORY] eq $category,
@{ $db->{by_date}{$last_date} };
}
sub max {
my $type = shift;
my $max = $_[0];
{ num => sub { $_ > $max },
str => sub { $_ gt $max},
}->{$type}->() and $max = $_
for @_[ 1 .. $#_ ];
return $max
}
sub print_latest_for_categories {
build_indexes( my $db = load(), 1, 1 );
for my $category (sort keys %{ $db->{by_category} }){
say "* $category";
_print_latest($db, $category);
}
}
sub print_all {
build_indexes( my $db = load(), 0, 1 );
for my $date (sort keys %{ $db->{by_date} }) {
for my $id (@{ $db->{by_date}{$date} }) {
say $db->{by_id}{$id}[NAME];
}
}
}
sub load {
open my $in, '<', DB or die "Can't open database: $!\n";
local $/;
return { by_id => decode_json(<$in>) };
}
sub save {
my ($db) = @_;
open my $out, '>', DB or die "Can't save database: $!\n";
print {$out} encode_json($db->{by_id});
close $out;
}
sub build_indexes {
my ($db, $by_category, $by_date) = @_;
for my $id (keys %{ $db->{by_id} }) {
push @{ $db->{by_category}{ $db->{by_id}{$id}[CATEGORY] } }, $id
if $by_category;
push @{ $db->{by_date}{ $db->{by_id}{$id}[DATE] } }, $id
if $by_date;
}
}</lang>
Sample session
~ $ db.pl n 'Donald Trump' Republican 2017-01-20 ~ $ db.pl n 'Barack Obama' Democratic 2009-01-20 ~ $ db.pl n 'Bill Clinton' Democratic 1993-01-20 ~ $ db.pl n 'George W. Bush' Republican 2001-01-20 ~ $ db.pl a Bill Clinton George W. Bush Barack Obama Donald Trump ~ $ db.pl l Donald Trump ~ $ db.pl L * Democratic Barack Obama * Republican Donald Trump
Phix
<lang Phix>-- -- demo\rosetta\Simple_db.exw -- ========================== -- include timedate.e
constant filename = getenv(iff(platform()=WINDOWS?"APPDATA":"HOME"))&"/simple_db.csv"
procedure add(sequence cmd)
if length(cmd)=0
or length(cmd)>2 then
printf(1,"usage: add name [cat]\n")
else
string name = cmd[1]
string cat = iff(length(cmd)=2?cmd[2]:"none")
string datestr = format_timedate(date(),"YYYY/MM/DD h:mmpm")
integer fn = open(filename,"a")
printf(fn,"%s,%s,%s\n",{name,cat,datestr})
close(fn)
end if
end procedure
procedure last(sequence cmd)
integer fn = open(filename,"r")
if fn=-1 then
puts(1,"file not found\n")
return
end if
integer lc = length(cmd)
string last = iff(lc?"<no entries for that category>\n":"<empty>\n")
while 1 do
object line = gets(fn)
if atom(line) then exit end if
if lc=0 or split(line,',')[2]=cmd[1] then
last = line
end if
end while
puts(1,last)
close(fn)
end procedure
sequence dates
function by_date(integer d1, integer d2)
return compare(dates[d1],dates[d2])
end function constant r_by_date = routine_id("by_date")
procedure sort_by_date() -- (simple_db.csv should be edited manually to prove the date sort works)
integer fn = open(filename,"r")
if fn=-1 then
puts(1,"file not found\n")
return
end if
sequence lines = {}
dates = {}
while 1 do
object line = gets(fn)
if atom(line) then exit end if
lines = append(lines,line)
dates = append(dates,split(line,',')[3])
end while
close(fn)
sequence tags = custom_sort(r_by_date,tagset(length(lines)))
for i=1 to length(tags) do
puts(1,lines[tags[i]])
end for
end procedure
procedure process(sequence cmd)
switch cmd[1] do
case "add": add(cmd[2..$])
case "last": last(cmd[2..$])
case "sort": sort_by_date()
default: printf(1,"unknown command: %s\n",{cmd[1]})
end switch
end procedure
constant helptext = """ p demo\rosetta\Simple_db -- interactive mode, commands as below p demo\rosetta\Simple_db add name [cat] -- add entry p demo\rosetta\Simple_db last [cat] -- show last entry [in specified category] p demo\rosetta\Simple_db sort -- show full list sorted by date """ sequence cl = command_line()
if length(cl)<3 then
-- interactive mode
puts(1,helptext)
while 1 do
puts(1,">")
object line = trim(gets(0))
if atom(line) or length(line)=0 then exit end if
puts(1,"\n")
process(split(line))
end while
else
process(cl[3..$])
end if</lang>
Sample session
C:\Program Files (x86)\Phix>p demo\rosetta\simple_db p demo\rosetta\Simple_db -- interactive mode, commands as below p demo\rosetta\Simple_db add name [cat] -- add entry p demo\rosetta\Simple_db last [cat] -- show last entry [in specified category] p demo\rosetta\Simple_db sort -- show full list sorted by date >sort fred,none,2016/07/25 12:30pm cliff,none,2016/07/25 12:31pm barney,none,2016/07/25 12:32pm one,two,2016/07/25 12:33pm >add three four >sort fred,none,2016/07/25 12:30pm cliff,none,2016/07/25 12:31pm barney,none,2016/07/25 12:32pm one,two,2016/07/25 12:33pm three,four,2016/07/25 12:39pm >last three,four,2016/07/25 12:39pm >last one <no entries for that category> >last two one,two,2016/07/25 12:33pm >
PicoLisp
The 'rc' resource file handling function is used typically for such tasks. It also takes care of proper locking and protection. <lang PicoLisp>#!/usr/bin/pil
(de usage ()
(prinl
"Usage:^J\
sdb <file> add <title> <cat> <date> ... Add a new entry^J\
sdb <file> get <title> Retrieve an entry^J\
sdb <file> latest Print the latest entry^J\
sdb <file> categories Print the latest for each cat^J\
sdb <file> Print all, sorted by date" ) )
(de printEntry (E)
(apply println (cdddr E) (car E) (cadr E) (datStr (caddr E))) )
(ifn (setq *File (opt))
(usage)
(case (opt)
(add
(let (Ttl (opt) Cat (opt))
(if (strDat (opt))
(rc *File Ttl (cons Cat @ (argv)))
(prinl "Bad date") ) ) )
(get
(let Ttl (opt)
(when (rc *File Ttl)
(printEntry (cons Ttl @)) ) ) )
(latest
(printEntry (maxi caddr (in *File (read)))) )
(categories
(for Cat (by cadr group (in *File (read)))
(printEntry (maxi caddr Cat)) ) )
(NIL
(mapc printEntry (by caddr sort (in *File (read)))) )
(T (usage)) ) )
(bye)</lang> Test:
$ sdb CDs add "Title 1" "Category 1" 2011-11-13 $ sdb CDs add "Title 2" "Category 2" 2011-11-12 $ sdb CDs add "Title 3" "Category 1" 2011-11-14 foo bar $ sdb CDs add "Title 4" "Category 2" 2011-11-15 mumble $ sdb CDs get "Title 3" "Title 3" "Category 1" "2011-11-14" "foo" "bar" $ sdb CDs latest "Title 4" "Category 2" "2011-11-15" "mumble" $ sdb CDs categories "Title 4" "Category 2" "2011-11-15" "mumble" "Title 3" "Category 1" "2011-11-14" "foo" "bar" $ sdb CDs "Title 2" "Category 2" "2011-11-12" "Title 1" "Category 1" "2011-11-13" "Title 3" "Category 1" "2011-11-14" "foo" "bar" "Title 4" "Category 2" "2011-11-15" "mumble"
Pike
(simplified)
<lang Pike>mapping db = ([]);
mapping make_episode(string series, string title, string episode, array date) {
return ([ "series":series, "episode":episode, "title":title, "date":date ]);
}
void print_episode(mapping episode) {
write(" %-30s %10s %-30s (%{%d.%})\n",
episode->series, episode->episode, episode->title, episode->date);
}
void print_series(mapping series) {
write("%-30s %-10s\n", series->series, series->status);
map(series->episodes, print_episode);
}
void dump_db(mapping database) {
foreach(database; string name; mapping series)
{
print_series(series);
}
}
array get_latest(mapping database) {
array latest = ({});
foreach(database; string name; mapping series)
{
latest += ({ series->episodes[0] });
}
return latest;
}
int(0..1) compare_date(array a, array b) {
if (!arrayp(a) && !arrayp(b)) return false; if (!arrayp(a) || !sizeof(a)) return arrayp(b) && sizeof(b); if (!arrayp(b) || !sizeof(b)) return arrayp(a) && sizeof(a); if (a[0] == b[0]) return compare_date(a[1..], b[1..]); return a[0] < b[0];
}
int(0..1) compare_by_date(mapping a, mapping b) {
return compare_date(reverse(a->date), reverse(b->date));
}
void watch_list(mapping database) {
map(Array.sort_array(get_latest(database), compare_by_date),
print_episode);
}
string prompt_read(string prompt) {
write("%s: ", prompt);
return Stdio.stdin.gets();
}
array parse_date(string date) {
return (array(int))(date/".");
}
mapping prompt_for_episode() {
return make_episode(prompt_read("Series"),
prompt_read("Title"),
prompt_read("Episode"),
parse_date(prompt_read("Date watched")));
}
// pike offers encode_value() and decode_value() as standard ways // to save and read data, but that is not a human readable format. // therefore we are instead printing the structure as debug-output // which is a readable form as long as it only contains integers, // strings, mappings, arrays and multisets this format can be read by pike. // to read it we are creating a class that contains the data as a value, // which is then compiled and instantiated to allow us to pull the data out. void save_db(string filename, mapping database) {
Stdio.write_file(filename, sprintf("%O", database));
}
void watch_save() {
save_db("pwatch", db);
}
mapping load_db(string filename) {
if (file_stat(filename))
return compile_string("mixed data = " +
Stdio.read_file(filename) + ";")()->data;
else return ([]);
}
mapping get_series(string name, mapping database) {
return database[name];
}
array get_episode_list(string series, mapping database) {
return database[series]->episodes;
}
void watch_new_series(string name, string status, mapping database) {
database[name] = (["series":name, "status":status, "episodes":({}) ]);
}
mapping get_or_add_series(string name, mapping database) {
if (!database[name])
{
string answer = prompt_read("Add new series? [y/n]: ");
if (answer == "y")
watch_new_series(name, "active", database);
}
return database[name];
}
void watch_add(mapping database) {
mapping episode = prompt_for_episode();
string series_name = episode->series;
mapping series = get_or_add_series(series_name, database);
if (!series)
watch_add(database);
else
series->episodes = Array.unshift(series->episodes, episode);
}
void watch_load() {
db = load_db("pwatch");
}
int main(int argc, array argv) {
watch_load();
if (argc>1 && argv[1] == "add")
{
watch_add(db);
watch_save();
}
else
watch_list(db);
}</lang>
PowerShell
<lang PowerShell> function db {
[CmdletBinding(DefaultParameterSetName="None")]
[OutputType([PSCustomObject])]
Param
(
[Parameter(Mandatory=$false,
Position=0,
ParameterSetName="Add a new entry")]
[string]
$Path = ".\SimpleDatabase.csv",
[Parameter(Mandatory=$true,
ParameterSetName="Add a new entry")]
[string]
$Name,
[Parameter(Mandatory=$true,
ParameterSetName="Add a new entry")]
[string]
$Category,
[Parameter(Mandatory=$true,
ParameterSetName="Add a new entry")]
[datetime]
$Birthday,
[Parameter(ParameterSetName="Print the latest entry")]
[switch]
$Latest,
[Parameter(ParameterSetName="Print the latest entry for each category")]
[switch]
$LatestByCategory,
[Parameter(ParameterSetName="Print all entries sorted by a date")]
[switch]
$SortedByDate
)
if (-not (Test-Path -Path $Path))
{
'"Name","Category","Birthday"' | Out-File -FilePath $Path
}
$db = Import-Csv -Path $Path | Foreach-Object {
$_.Birthday = $_.Birthday -as [datetime]
$_
}
switch ($PSCmdlet.ParameterSetName)
{
"Add a new entry"
{
[PSCustomObject]@{Name=$Name; Category=$Category; Birthday=$Birthday} | Export-Csv -Path $Path -Append
}
"Print the latest entry"
{
$db[-1]
}
"Print the latest entry for each category"
{
($db | Group-Object -Property Category).Name | ForEach-Object {($db | Where-Object -Property Category -Contains $_)[-1]}
}
"Print all entries sorted by a date"
{
$db | Sort-Object -Property Birthday
}
Default
{
$db
}
}
}
db -Name Bev -Category friend -Birthday 3/3/1983 db -Name Bob -Category family -Birthday 7/19/1987 db -Name Gill -Category friend -Birthday 12/9/1986 db -Name Gail -Category family -Birthday 2/11/1986 db -Name Vince -Category family -Birthday 3/10/1960 db -Name Wayne -Category coworker -Birthday 5/29/1962 </lang> Here is the data from the CSV file as a PowerShell Object: <lang PowerShell> db </lang>
- Output:
Name Category Birthday ---- -------- -------- Bev friend 3/3/1983 12:00:00 AM Bob family 7/19/1987 12:00:00 AM Gill friend 12/9/1986 12:00:00 AM Gail family 2/11/1986 12:00:00 AM Vince family 3/10/1960 12:00:00 AM Wayne coworker 5/29/1962 12:00:00 AM
The latest entry: <lang PowerShell> db -Latest </lang>
- Output:
Name Category Birthday ---- -------- -------- Wayne coworker 5/29/1962 12:00:00 AM
The latest entries by category: <lang PowerShell> db -LatestByCategory </lang>
- Output:
Name Category Birthday ---- -------- -------- Gill friend 12/9/1986 12:00:00 AM Vince family 3/10/1960 12:00:00 AM Wayne coworker 5/29/1962 12:00:00 AM
The database sorted on the Birthday property: <lang PowerShell> db -SortedByDate </lang>
- Output:
Name Category Birthday ---- -------- -------- Vince family 3/10/1960 12:00:00 AM Wayne coworker 5/29/1962 12:00:00 AM Bev friend 3/3/1983 12:00:00 AM Gail family 2/11/1986 12:00:00 AM Gill friend 12/9/1986 12:00:00 AM Bob family 7/19/1987 12:00:00 AM
Python
<lang python>#!/usr/bin/python3
\ Simple database for: http://rosettacode.org/wiki/Simple_database
import argparse from argparse import Namespace import datetime import shlex
def parse_args():
'Set up, parse, and return arguments' parser = argparse.ArgumentParser(epilog=globals()['__doc__'])
parser.add_argument('command', choices='add pl plc pa'.split(),
help=\
add: Add a new entry pl: Print the latest entry plc: Print the latest entry for each category/tag pa: Print all entries sorted by a date)
parser.add_argument('-d', '--description',
help='A description of the item. (e.g., title, name)')
parser.add_argument('-t', '--tag',
help=(A category or tag (genre, topic, relationship
such as “friend” or “family”)))
parser.add_argument('-f', '--field', nargs=2, action='append',
help='Other optional fields with value (can be repeated)')
return parser
def do_add(args, dbname):
'Add a new entry'
if args.description is None:
args.description =
if args.tag is None:
args.tag =
del args.command
print('Writing record to %s' % dbname)
with open(dbname, 'a') as db:
db.write('%r\n' % args)
def do_pl(args, dbname):
'Print the latest entry'
print('Getting last record from %s' % dbname)
with open(dbname, 'r') as db:
for line in db: pass
record = eval(line)
del record._date
print(str(record))
def do_plc(args, dbname):
'Print the latest entry for each category/tag'
print('Getting latest record for each tag from %s' % dbname)
with open(dbname, 'r') as db:
records = [eval(line) for line in db]
tags = set(record.tag for record in records)
records.reverse()
for record in records:
if record.tag in tags:
del record._date
print(str(record))
tags.discard(record.tag)
if not tags: break
def do_pa(args, dbname):
'Print all entries sorted by a date'
print('Getting all records by date from %s' % dbname)
with open(dbname, 'r') as db:
records = [eval(line) for line in db]
for record in records:
del record._date
print(str(record))
def test():
import time
parser = parse_args()
for cmdline in [
"""-d Book -f title 'Windy places' -f type hardback --tag DISCOUNT add""",
"""-d Book -f title 'RC spammers' -f type paperback -t DISCOUNT add""",
"""-d Book -f title 'Splat it' -f type hardback -f special 'first edition' -t PREMIUM add""",
"""pl""",
"""plc""",
]:
args = parser.parse_args(shlex.split(cmdline))
now = datetime.datetime.utcnow()
args._date = now.isoformat()
do_command[args.command](args, dbname)
time.sleep(0.5)
do_command = dict(add=do_add, pl=do_pl, plc=do_plc, pa=do_pa) dbname = '_simple_db_db.py'
if __name__ == '__main__':
if 0:
test()
else:
parser = parse_args()
args = parser.parse_args()
now = datetime.datetime.utcnow()
args._date = now.isoformat()
do_command[args.command](args, dbname)</lang>
- Sample session (Unix)
paddy3118:~$ ./simple_db.py -h
usage: simple_db.py [-h] [-d DESCRIPTION] [-t TAG] [-f FIELD FIELD]
{add,pl,plc,pa}
positional arguments:
{add,pl,plc,pa} add: Add a new entry pl: Print the latest entry plc:
Print the latest entry for each category/tag pa: Print
all entries sorted by a date
optional arguments:
-h, --help show this help message and exit
-d DESCRIPTION, --description DESCRIPTION
A description of the item. (e.g., title, name)
-t TAG, --tag TAG A category or tag (genre, topic, relationship such as
“friend” or “family”)
-f FIELD FIELD, --field FIELD FIELD
Other optional fields with value (can be repeated)
Simple database for: http://rosettacode.org/wiki/Simple_database
paddy3118:~$ ./simple_db.py -d Book -f title 'Windy places' -f type hardback --tag DISCOUNT add
Writing record to _simple_db_db.py
paddy3118:~$ ./simple_db.py -d Book -f title 'RC spammers' -f type paperback -t DISCOUNT add
Writing record to _simple_db_db.py
paddy3118:~$ ./simple_db.py -d Book -f title 'Splat it' -f type hardback -f special 'first edition' -t PREMIUM add
Writing record to _simple_db_db.py
paddy3118:~$ ./simple_db.py pl
Getting last record from _simple_db_db.py
Namespace(description='Book', field=[['title', 'Splat it'], ['type', 'hardback'], ['special', 'first edition']], tag='PREMIUM')
paddy3118:~$ ./simple_db.py plc
Getting latest record for each tag from _simple_db_db.py
Namespace(description='Book', field=[['title', 'Splat it'], ['type', 'hardback'], ['special', 'first edition']], tag='PREMIUM')
Namespace(description='Book', field=[['title', 'RC spammers'], ['type', 'paperback']], tag='DISCOUNT')
paddy3118:~$ ./simple_db.py pa
Getting all records by date from _simple_db_db.py
Namespace(description='Book', field=[['title', 'Windy places'], ['type', 'hardback']], tag='DISCOUNT')
Namespace(description='Book', field=[['title', 'RC spammers'], ['type', 'paperback']], tag='DISCOUNT')
Namespace(description='Book', field=[['title', 'Splat it'], ['type', 'hardback'], ['special', 'first edition']], tag='PREMIUM')
paddy3118:~$
paddy3118:~$ cat _simple_db_db.py
Namespace(_date='2012-08-18T06:02:44.947091', description='Book', field=[['title', 'Windy places'], ['type', 'hardback']], tag='DISCOUNT')
Namespace(_date='2012-08-18T06:03:11.477429', description='Book', field=[['title', 'RC spammers'], ['type', 'paperback']], tag='DISCOUNT')
Namespace(_date='2012-08-18T06:03:34.319799', description='Book', field=[['title', 'Splat it'], ['type', 'hardback'], ['special', 'first edition']], tag='PREMIUM')
paddy3118:~$
Racket
<lang racket>
- !/usr/bin/env racket
- lang racket
(define (*write file data) ; write data in human readable format (sexpr/line)
(with-output-to-file file #:exists 'replace (lambda () (for ([x data]) (printf "~s\n" x)))))
(define *read file->list) ; read our "human readable format"
(command-line
#:once-any
[("-a") file title category date "Add an entry"
(*write file `(,@(*read file) (,title ,category ,date)))]
[("-d") file title "Delete an entry (all matching)"
(*write file (filter-not (lambda (x) (equal? (car x) title)) (*read file)))]
[("-p") file mode "Print entries, mode = latest, latest/cat, all, by-date"
(define data (*read file))
(define (show item)
(match item [(list title cat date) (printf "[~a] ~a; ~a\n" cat title date)]))
(case (string->symbol mode)
[(all) (for-each show data)]
[(by-date) (for-each show (sort data string<? #:key cadr))]
[(latest) (show (last data))]
[(latest/cat)
(define (last/cat c) (for/last ([x data] #:when (equal? c (cadr x))) x))
(for-each (compose1 show last/cat) (remove-duplicates (map cadr data)))]
[else (error 'sdb "bad printout mode")])])
</lang>
Sample run:
$ ./sdb -h sdb [ <option> ... ] where <option> is one of / -a <file> <title> <category> <date> : Add an entry | -d <file> <title> : Delete an entry (all matching) \ -p <file> <mode> : Print entries, mode = latest, latest/cat, all --help, -h : Show this help -- : Do not treat any remaining argument as a switch (at this level) /|\ Brackets indicate mutually exclusive options. Multiple single-letter switches can be combined after one `-'; for example: `-h-' is the same as `-h --' $ ./sdb -a Stuffs A-Book books 2013-01-01 $ ./sdb -a Stuffs Another-Book books 2013-01-02 $ ./sdb -a Stuffs Some-CD cds 2013-01-03 $ ./sdb -a Stuffs A-Bad-CD cds 2013-01-04 $ ./sdb -p Stuffs all [books] A-Book; 2013-01-01 [books] Another-Book; 2013-01-02 [cds] Some-CD; 2013-01-03 [cds] A-Bad-CD; 2013-01-04 $ ./sdb -p Stuffs latest [cds] A-Bad-CD; 2013-01-04 $ ./sdb -p Stuffs latest/cat [books] Another-Book; 2013-01-02 [cds] A-Bad-CD; 2013-01-04 $ ./sdb -d Stuffs A-Bad-CD $ ./sdb -p Stuffs by-date [books] A-Book; 2013-01-01 [books] Another-Book; 2013-01-02 [cds] Some-CD; 2013-01-03
REBOL
<lang rebol>rebol [author: "Nick Antonaccio"] write/append %rdb "" db: load %rdb switch system/options/args/1 [
"new" [write/append %rdb rejoin [now " " mold/only next system/options/args newline]]
"latest" [print copy/part tail sort/skip db 4 -4]
"latestcat" [
foreach cat unique extract at db 3 4 [
t: copy []
foreach [a b c d] db [if c = cat [append t reduce [a b c d]]]
print copy/part tail sort/skip t 4 -4
]
]
"sort" [probe sort/skip db 4]
] halt</lang>
REXX
<lang rexx>/* REXX ---------------------------------------------------------------
- 05.10.2014
- --------------------------------------------------------------------*/
x05='05'x mydb='sidb.txt' Say 'Enter your commands, ?, or end' Do Forever
Parse Pull l
Parse Var l command text
Select
When command='?' Then
Call help
When command='add' Then Do
Parse Var text item ',' category ',' date
If date= Then
date=date('S') /*yyyymmdd*/
Say 'adding item' item'/'category 'dated' date
Call lineout mydb,date item x05 category
End
When command='latest' Then Do
Call lineout mydb
Parse Var text category
hidt='00000000'
ol=
Do While lines(mydb)>0
l=linein(mydb)
Parse Var l dt a (x05) b
If category=|,
category='-' & b= |,
b=category Then Do
If dt>>hidt Then Do
ol=l
hidt=dt
End
End
End
If ol> Then
Call o ol
Else
Say 'no matching item found'
End
When command='all' Then Do
Call lineout mydb
Parse Var text category
Do While lines(mydb)>0
l=linein(mydb)
Parse Var l a (x05) b
If category=|,
category='-' & b=|,
b=category Then
Call o l
End
End
When command='end' Then
Leave
Otherwise Do
Say 'invalid command ('command')'
Call help
End
End
End
Say 'Bye' Exit
o: Parse Value arg(1) With dt text
Say left(dt,8) text Return
help:
Say 'add item[,[category][,date]] to add an item' Say 'latest category to list the latest item of a category' Say 'latest to list the latest item' Say 'all category to list all items of a category' Say 'all to list all items' Say 'end to end this program' Say 'Use category - to list items without category' Return</lang>
- Output:
Enter your commands, ?, or end ? add item[,[category][,date]] to add an item latest category to list the latest item of a category latest to list the latest item all category to list all items of a category all to list all items end to end this program Use category - to list items without category add item1 adding item item1/ dated 20141006 add item2 adding item item2/ dated 20141006 add item3,cat3 adding item item3/cat3 dated 20141006 add item4,cat3,20201910 adding item item4/cat3 dated 20201910 add item5,cat3,190201910 adding item item5/cat3 dated 190201910 all 20141006 item1 � 20141006 item2 � 20141006 item3 � cat3 20201910 item4 � cat3 190201910 item5 � cat3 latest 20201910 item4 � cat3 latest cat1 no matching item found latest cat3 20201910 item4 � cat3 end Bye
Ruby
<lang ruby>require 'date' require 'json' require 'securerandom'
class SimpleDatabase
def initialize(dbname, *fields)
@dbname = dbname
@filename = @dbname + ".dat"
@fields = fields
@maxl = @fields.collect {|f| f.length}.max
@data = {
'fields' => fields,
'items' => {},
'history' => [],
'tags' => {},
}
end
attr_reader :dbname, :fields
def self.open(dbname) db = new(dbname) db.read db end
def read()
if not File.exists?(@filename)
raise ArgumentError, "Database #@dbname has not been created"
end
@data = JSON.parse(File.read(@filename))
@fields = @data['fields']
@maxl = @fields.collect {|f| f.length}.max
end
def write()
File.open(@filename, 'w') {|f| f.write(JSON.generate(@data))}
end
def add(*values) id = SecureRandom.uuid @data['items'][id] = Hash[ @fields.zip(values) ] @data['history'] << [Time.now.to_f, id] id end
def tag(id, *tags)
tags.each do |tag|
if @data['tags'][tag].nil?
@data['tags'][tag] = [id]
else
@data['tags'][tag] << id
end
end
id
end
def latest
@data['history'].sort_by {|val| val[0]}.last.last
end
def get_item(id) @data['items'][id] end
def tags() @data['tags'].keys.sort end
def ids_for_tag(tag) @data['tags'][tag] end
def tags_for_id(id)
@data['tags'].keys.inject([]) do |tags, tag|
tags << tag if @data['tags'][tag].include?(id)
tags
end
end
def display(id)
item = get_item(id)
fmt = "%#{@maxl}s - %s\n"
puts fmt % ['id', id]
@fields.each {|f| print fmt % [f, item[f]]}
puts fmt % ['tags', tags_for_id(id).join(',')]
added = @data['history'].find {|x| x[1] == id}.first
puts fmt % ['date added', Time.at(added).ctime]
puts ""
end
def each()
@data['history'].each {|time, id| yield id}
end
def each_item_with_tag(tag)
@data['tags'][tag].each {|id| yield id}
end
end def usage()
puts <<END
usage: #{$0} command args ...
commands:
help create dbname field ... fields dbname add dbname value ... tag dbname id tag ... tags dbname list dbname [tag ...] latest dbname latest_by_tag dbname
END end
def open_database(args)
dbname = args.shift begin SimpleDatabase.open(dbname) rescue ArgumentError => e STDERR.puts e.message exit 1 end
end
def process_command_line(command, *args)
case command when 'help' usage
when 'create'
db = SimpleDatabase.new(*args)
db.write
puts "Database #{args[0]} created"
when 'fields'
db = open_database(args)
puts "Database #{db.dbname} fields:"
puts db.fields.join(',')
when 'add'
db = open_database(args)
id = db.add(*args)
db.write
puts "Database #{db.dbname} added id #{id}"
when 'tag'
db = open_database(args)
id = args.shift
db.tag(id, *args)
db.write
db.display(id)
when 'tags'
db = open_database(args)
puts "Database #{db.dbname} tags:"
puts db.tags.join(',')
when 'list'
db = open_database(args)
if args.empty?
db.each {|id| db.display(id)}
else
args.each do |tag|
puts "Items tagged #{tag}"
db.each_item_with_tag(tag) {|id| db.display(id)}
end
end
when 'latest' db = open_database(args) db.display(db.latest)
when 'latest_by_tag'
db = open_database(args)
db.tags.each do |tag|
puts tag
db.display(db.ids_for_tag(tag).last)
end
else
puts "Error: unknown command '#{command}'"
usage
end
end
process_command_line *ARGV</lang>
Sample session
$ ruby simple_database.rb create appointments event_title start_time stop_time location event_description
Database appointments created
$ ruby simple_database.rb add appointments "Wife's Birthday" "2011-11-01" "2011-11-01" "" "happy 39th"
Database appointments added id 6dd02195-1efe-40d1-b43e-c2efd852cd1d
$ ruby simple_database.rb tag appointments 6dd02195-1efe-40d1-b43e-c2efd852cd1d birthday family
id - 6dd02195-1efe-40d1-b43e-c2efd852cd1d
event_title - Wife's Birthday
start_time - 2011-11-01
stop_time - 2011-11-01
location -
event_description - happy 39th
tags - birthday,family
date added - Thu Nov 3 15:52:31 2011
$ ruby simple_database.rb add appointments "Parent-Teacher Conference" "2011-11-03 19:30" "2011-11-03 20:00" "school" "desc"
Database appointments added id 0190b835-401d-42da-9ed3-1d335d27b83c
$ ruby simple_database.rb tag appointments 0190b835-401d-42da-9ed3-1d335d27b83c school family
id - 0190b835-401d-42da-9ed3-1d335d27b83c
event_title - Parent-Teacher Conference
start_time - 2011-11-03 19:30
stop_time - 2011-11-03 20:00
location - school
event_description - desc
tags - family,school
date added - Thu Nov 3 15:54:05 2011
$ ruby simple_database.rb add appointments "Buy gift for wife" "2011-10-31 16:00" "2011-10-31 16:30" "the mall" "hmm, maybe jewelery?"
Database appointments added id 4023e6f1-bcc1-49e5-a59f-138157b413f4
$ ruby simple_database.rb tag appointments 4023e6f1-bcc1-49e5-a59f-138157b413f4 family last-minute
id - 4023e6f1-bcc1-49e5-a59f-138157b413f4
event_title - Buy gift for wife
start_time - 2011-10-31 16:00
stop_time - 2011-10-31 16:30
location - the mall
event_description - hmm, maybe jewelery?
tags - family,last-minute
date added - Thu Nov 3 15:55:02 2011
$ ruby simple_database.rb fields appointments
Database appointments fields:
event_title,start_time,stop_time,location,event_description
$ ruby simple_database.rb tags appointments
Database appointments tags:
birthday,family,last-minute,school
$ ruby simple_database.rb list appointments
id - 6dd02195-1efe-40d1-b43e-c2efd852cd1d
event_title - Wife's Birthday
start_time - 2011-11-01
stop_time - 2011-11-01
location -
event_description - happy 39th
tags - birthday,family
date added - Thu Nov 3 15:52:31 2011
id - 0190b835-401d-42da-9ed3-1d335d27b83c
event_title - Parent-Teacher Conference
start_time - 2011-11-03 19:30
stop_time - 2011-11-03 20:00
location - school
event_description - desc
tags - family,school
date added - Thu Nov 3 15:54:05 2011
id - 4023e6f1-bcc1-49e5-a59f-138157b413f4
event_title - Buy gift for wife
start_time - 2011-10-31 16:00
stop_time - 2011-10-31 16:30
location - the mall
event_description - hmm, maybe jewelery?
tags - family,last-minute
date added - Thu Nov 3 15:55:02 2011
$ cat appointments.dat
{"fields":["event_title","start_time","stop_time","location","event_description"],"items":{"6dd02195-1efe-40d1-b43e-c2efd852cd1d":{"event_title":"Wife's Birthday","start_time":"2011-11-01","stop_time":"2011-11-01","location":"","event_description":"happy 39th"},"0190b835-401d-42da-9ed3-1d335d27b83c":{"event_title":"Parent-Teacher Conference","start_time":"2011-11-03 19:30","stop_time":"2011-11-03 20:00","location":"school","event_description":"desc"},"4023e6f1-bcc1-49e5-a59f-138157b413f4":{"event_title":"Buy gift for wife","start_time":"2011-10-31 16:00","stop_time":"2011-10-31 16:30","location":"the mall","event_description":"hmm, maybe jewelery?"}},"history":[[1320349951.000625,"6dd02195-1efe-40d1-b43e-c2efd852cd1d"],[1320350045.4736252,"0190b835-401d-42da-9ed3-1d335d27b83c"],[1320350102.9486248,"4023e6f1-bcc1-49e5-a59f-138157b413f4"]],"tags":{"birthday":["6dd02195-1efe-40d1-b43e-c2efd852cd1d"],"family":["6dd02195-1efe-40d1-b43e-c2efd852cd1d","0190b835-401d-42da-9ed3-1d335d27b83c","4023e6f1-bcc1-49e5-a59f-138157b413f4"],"school":["0190b835-401d-42da-9ed3-1d335d27b83c"],"last-minute":["4023e6f1-bcc1-49e5-a59f-138157b413f4"]}}
Run BASIC
<lang runbasic>sqliteconnect #sql, "f:\client.db" ' Connect to the DB
' ------------------------------- ' show user options ' ------------------------------- [sho] cls ' clear screen button #acd, "Add a new entry", [add] button #acd, "Print the latest entry", [last] button #acd, "Print the latest entry for each category", [lastCat] button #acd, "Print all entries sorted by a date", [date] button #ex, "Exit", [exit] wait
' ------------------------------------ ' add a new entry (user input screen) ' ------------------------------------ [add] cls ' clear the screen
html "
" html "" html "| Client Maintenance | |
| Client Num | "
textbox #clientNum,clientNum$,5html " |
| Name | "
textbox #name,name$,30html " |
| Client Date | "
textbox #clientDate,clientDate$,19html " |
| Category | "
textbox #category,category$,10html " |
"
button #acd, "Add", [addIt]
button #ex, "Exit", [sho]
html " | |
"
wait
' --------------------------------------------- ' Get data from the screen ' --------------------------------------------- [addIt] clientNum = #clientNum contents$() name$ = trim$(#name contents$()) clientDate$ = trim$(#clientDate contents$()) category$ = trim$(#category contents$()) dbVals$ = clientNum;",'";name$;"','";clientDate$;"','";category$;"'" sql$ = "INSERT into client VALUES ("; dbVals$ ; ")"
- sql execute(sql$)
goto [sho]
' ------------------------------------ ' Select last entry ' ------------------------------------ [last] sql$ = "SELECT *,client.rowid as rowid FROM client ORDER BY rowid desc LIMIT 1" what$ = "---- Last Entry ----" goto [shoQuery]
' ------------------------------------ ' Select by category (Last date only) ' ------------------------------------ [lastCat] sql$ = "SELECT * FROM client WHERE client.clientDate = (SELECT max(c.clientDate) FROM client as c WHERE c.category = client.category) ORDER BY category" what$ = "---- Last Category Sequence ----" goto [shoQuery]
' ------------------------------------ ' Select by date ' ------------------------------------ [date] sql$ = "SELECT * FROM client ORDER BY clientDate" what$ = "---- By Date ----"
[shoQuery] cls print what$
html "
" html "" ' heading- sql execute(sql$)
WHILE #sql hasanswer()
#row = #sql #nextrow() clientNum = #row clientNum() name$ = #row name$() clientDate$ = #row clientDate$() category$ = #row category$()html ""
WEND
html "| Client Num | Name | Client Date | Category |
| ";clientNum;" | ";name$;" | ";clientDate$;" | ";category$;" |
"
button #c, "Continue", [sho] wait
' ------ the end ------- [exit] end</lang> Output:
User Input ----
| Client Maintenance | |
| Client Num | 5 |
| Name | Dawnridge Winery |
| Client Date | 2008-06-18 22:16 |
| Category | wine |
| [Add] [Exit] | |
Last Entry ----
| Client Num | Name | Client Date | Category |
| 5 | Dawnridge Winery | 2008-06-18 22:16 | wine |
Last category Sequence ----
| Client Num | Name | Client Date | Category |
| 1 | Home Sales | 2012-01-01 10;20 | broker |
| 4 | Back 40 Equipment | 2009-09-18 20:18 | farm |
| 3 | Floral Designs | 2010-10-14 09:16 | flowers |
| 2 | Best Foods | 2011-02-02 12:33 | food |
| 5 | Dawnridge Winery | 2008-06-18 22:16 | wine |
Date Sequence ----
| Client Num | Name | Client Date | Category |
| 5 | Dawnridge Winery | 2008-06-18 22;16 | wine |
| 4 | Back 40 Equipment | 2009-09-18 20:18 | farm |
| 3 | Floral Designs | 2010-10-14 09:16 | flowers |
| 2 | Best Foods | 2011-02-02 12:33 | food |
| 1 | Home Sales | 2012-01-01 10:20 | broker |
Scala
<lang Scala>object SimpleDatabase extends App {
type Entry = Array[String]
def asTSV(e: Entry) = e mkString "\t"
def fromTSV(s: String) = s split "\t"
val header = asTSV(Array("TIMESTAMP", "DESCRIPTION", "CATEGORY", "OTHER"))
def read(filename: String) = try {
scala.io.Source.fromFile(filename).getLines.drop(1).map(fromTSV)
} catch {
case e: java.io.FileNotFoundException => Nil
}
def write(filename: String, all: Seq[Entry]) = {
import java.nio.file.{Files,Paths}
import scala.collection.JavaConversions.asJavaIterable
Files.write(Paths.get(filename), asJavaIterable(header +: all.map(asTSV)))
all.size
}
def add(filename: String, description: String, category: String = "none", optional: Seq[String] = Nil) {
val format = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
val e = Array(format.format(new java.util.Date), description, category) ++ optional
println(write(filename, read(filename).toBuffer :+ e) + " entries")
}
def print(filename: String, filter: Seq[Entry] => TraversableOnce[Entry]) = filter(read(filename).toList.sortBy(_.headOption)) map(_ mkString ",") foreach println
args match {
case Array(f, "latest") => print(f, _ takeRight 1)
case Array(f, "latest", cat) => print(f, _ filter(_.lift(2) == Some(cat)) takeRight 1)
case Array(f, "all") => print(f, _.toSeq)
case Array(f, "all", "latest") => print(f, _ groupBy (_ lift 2 getOrElse "") map{case (_, cat) => cat.last})
case Array(f, "add", desc) => add(f, desc, category = "")
case Array(f, "add", desc, cat, opt @ _*) => add(f, desc, cat, opt)
case _ => println("Usage: SimpleDatabase filename.tsv [all [latest]| latest [CATEGORY] | add [DESCRIPTION [CATEGORY [OPTIONAL]...]]]")
}
}</lang>
- Output:
> SimpleDatabase Usage: SimpleDatabase filename.tsv [all [latest]| latest [CATEGORY] | add [DESCRIPTION [CATEGORY [OPTIONAL]...]]] > SimpleDatabase database.tsv all > SimpleDatabase database.tsv add one 1 entries > SimpleDatabase database.tsv add two test 2 entries > SimpleDatabase database.tsv add three test optional 3 entries > SimpleDatabase database.tsv add four final 4 entries > SimpleDatabase database.tsv all 2014-10-03 12:00:01,one 2014-10-03 12:00:02,two,test 2014-10-03 12:00:03,three,test,optional 2014-10-03 12:00:04,four,final > SimpleDatabase database.tsv all latest 2014-10-03 12:00:04,four,final 2014-10-03 12:00:03,three,test,optional 2014-10-03 12:00:01,one > SimpleDatabase database.tsv latest 2014-10-03 12:00:04,four,final > SimpleDatabase database.tsv latest test 2014-10-03 12:00:03,three,test,optional
Tcl
The format used is that of a Tcl dictionary, where each entry uses the title as a key and the remaining information (category, date and miscellaneous metadata) is the value associated with it. The only variation from the standard internal format is that entries are separated by newlines instead of spaces; this is still a legal value, but is a non-canonical. <lang tcl>#!/usr/bin/env tclsh8.6 package require Tcl 8.6 namespace eval udb {
variable db {}
proc Load {filename} {
variable db if {[catch {set f [open $filename]}]} { set db {} return } set db [read $f] close $f
}
proc Store {filename} {
variable db if {[catch {set f [open $filename w]}]} return dict for {nm inf} $db { puts $f [list $nm $inf] } close $f
}
proc add {title category {date "now"} args} {
variable db if {$date eq "now"} { set date [clock seconds] } else { set date [clock scan $date] } dict set db $title [list $category $date $args] return
}
proc Rec {nm cat date xtra} {
dict create description $nm category $cat date [clock format $date] \ {*}$xtra _names [dict keys $xtra]
} proc latest Template:Category "" {
variable db if {$category eq ""} { set d [lsort -stride 2 -index {1 1} -integer -decreasing $db] dict for {nm inf} $d break return [list [Rec $nm {*}$inf]] } set latestbycat {} dict for {nm inf} [lsort -stride 2 -index {1 1} -integer $db] { dict set latestbycat [lindex $inf 0] [list $nm {*}$inf] } return [list [Rec {*}[dict get $latestbycat $category]]]
}
proc latestpercategory {} {
variable db set latestbycat {} dict for {nm inf} [lsort -stride 2 -index {1 1} -integer $db] { dict set latestbycat [lindex $inf 0] [list $nm {*}$inf] } set result {} dict for {- inf} $latestbycat { lappend result [Rec {*}$inf] } return $result
}
proc bydate {} {
variable db set result {} dict for {nm inf} [lsort -stride 2 -index {1 1} -integer $db] { lappend result [Rec $nm {*}$inf] } return $result
}
namespace export add latest latestpercategory bydate namespace ensemble create
}
if {$argc < 2} {
puts stderr "wrong # args: should be \"$argv0 dbfile subcommand ?args...?\"" exit 1
} udb::Load [lindex $argv 0] set separator "" if {[catch {udb {*}[lrange $argv 1 end]} msg]} {
puts stderr [regsub "\"udb " $msg "\"$argv0 dbfile "] exit 1
} foreach row $msg {
puts -nonewline $separator
apply {row {
dict with row { puts "Title: $description" puts "Category: $category" puts "Date: $date" foreach v $_names { puts "${v}: [dict get $row $v]" } }
}} $row set separator [string repeat - 70]\n
}
udb::Store [lindex $argv 0]</lang> Sample session: <lang bash>bash$ udb.tcl db wrong # args: should be "udb.tcl dbfile subcommand ?args...?" bash$ udb.tcl db ? unknown or ambiguous subcommand "?": must be add, bydate, latest, or latestpercategory bash$ udb.tcl db add wrong # args: should be "udb.tcl dbfile add title category ?date? ?arg ...?" bash$ udb.tcl db add "Title 1" foo bash$ udb.tcl db add "Title 2" foo bash$ udb.tcl db add "Title 3" bar bash$ udb.tcl db bydate Title: Title 1 Category: foo Date: Tue Nov 15 18:11:58 GMT 2011
Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011
Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ udb.tcl db latest Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ udb.tcl db latest foo Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011 bash$ udb.tcl db latest bar Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ udb.tcl db latestpercategory Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011
Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ udb.tcl db add "Title 4" bar "12:00 Monday last week" bash$ udb.tcl db bydate Title: Title 4 Category: bar Date: Mon Nov 14 12:00:00 GMT 2011
Title: Title 1 Category: foo Date: Tue Nov 15 18:11:58 GMT 2011
Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011
Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011 bash$ cat db {Title 1} {foo 1321380718 {}} {Title 2} {foo 1321380721 {}} {Title 3} {bar 1321380727 {}} {Title 4} {bar 1321272000 {}} bash$ udb.tcl db add "Title 5" foo "12:00 Monday last week" Comment 'Wholly excellent!' bash$ cat db {Title 1} {foo 1321380718 {}} {Title 2} {foo 1321380721 {}} {Title 3} {bar 1321380727 {}} {Title 4} {bar 1321272000 {}} {Title 5} {foo 1321272000 {Comment {Wholly excellent!}}} bash$ udb.tcl db bydate Title: Title 4 Category: bar Date: Mon Nov 14 12:00:00 GMT 2011
Title: Title 5 Category: foo Date: Mon Nov 14 12:00:00 GMT 2011 Comment: Wholly excellent!
Title: Title 1 Category: foo Date: Tue Nov 15 18:11:58 GMT 2011
Title: Title 2 Category: foo Date: Tue Nov 15 18:12:01 GMT 2011
Title: Title 3 Category: bar Date: Tue Nov 15 18:12:07 GMT 2011</lang>
ToffeeScript
<lang coffeescript>#!/usr/local/bin/toffee
prog = require 'commander' fs = require 'fs-extra'
if not fs.exists! 'data.json'
fs.outputJson! 'data.json', {}
prog
.command('add <name> <category> [date]')
.description('Add a new entry')
.option('-n <text>', 'notes')
.option('-t <tags>', 'tags')
.action addentry
prog
.command('latest')
.description('Print the latest entry')
.action latest
prog
.command('catlatest')
.description('Print the latest entry for each category')
.action catlatestout
prog
.command('list')
.description('Print all entries sorted by date')
.action bydate
addentry = (name, category, dt, options) ->
if dt? then dat = new Date(dt) else dat = new Date() update = name: name category: category tags: options?.T notes: options?.N date: dat.getTime() e, data = fs.readJson! 'data.json' if not data[category]? data[category] = [] data[category].push update fs.outputJson 'data.json', data
byDateNew = (a, b) ->
if a.date<b.date then return 1 if b.date>a.date then return -1 return 0
catlatest = (cb) ->
e, data = fs.readJson! 'data.json' ret = [] for cat, list of data list.sort byDateNew ret.push list[0] cb ret
printFormatted = (entry) ->
tmp = entry.date entry.date = new Date(entry.date).toDateString() console.log entry entry.date = tmp
latest = ->
newpercat = catlatest! newpercat.sort byDateNew printFormatted newpercat[0]
catlatestout = ->
items = catlatest! for item in items printFormatted item
bydate = ->
e, data = fs.readJson! 'data.json'
entries = []
for cat, list of data
for item in list
entries.push item
entries.sort byDateNew
for entry in entries
printFormatted entry
prog.parse process.argv</lang>
UNIX Shell
This format is guaranteed to be human readable: if you can type it, you can read it. <lang bash>#!/bin/sh
db_create() { mkdir ./"$1" && mkdir "./$1/.tag" && echo "Create DB \`$1'" }
db_delete() { rm -r ./"$1" && echo "Delete DB \`$1'" }
db_show() { if [ -z "$2" ]; then show_help; fi for x in "./$1/$2/"*; do echo "$x:" | sed "s/.*\///" cat "$x" | sed "s/^/ /" echo done
printf "Tags: " ls "./$1/$2/.tag" }
db_tag() { local db="$1" item="$2" shift shift for tag in $@; do mkdir "./$db/.tag/$tag" ln -s "$PWD/$db/$item" "./$db/.tag/$tag/" touch "./$db/$item/.tag/$tag" done }
show_help() { echo "Usage: $0 command [args]" echo "Commands:" cat $0 | grep ") ##" | grep -v grep | sed 's/) ## /:\t/' exit }
if [ -z "$1" ]; then show_help; fi
action=$1 it=database shift case $action in create) ## db -- create $it db_create "$@" ;;
drop) ## db -- delete $it db_delete "$@" ;;
add) ## db item -- add new item to $it mkdir -p "./$1/$2/.tag" && touch "./$1/$2/Description" ;;
rem) ## db item -- delete item from $it rm -r "./$1/$2" rm "./$1/.tag/"*"/$2" ;;
show) ## db item -- show item db_show "$@" ;;
newtag) ## db new-tag-name -- create new tag name mkdir "./$1/.tag/$2" ;;
prop) ## db item property-name property-content -- add property to item echo "$4" > "./$1/$2/$3" ;;
tag) ## db item tag [more-tags...] -- mark item with tags db_tag "$@" ;;
last) ## db -- show latest item ls "$1" --sort=time | tail -n 1 ;;
list) ## db -- list all items ls "$1" -1 --sort=time ;;
last-all) ## db -- list items in each category for x in "$1/.tag/"*; do echo "$x" | sed 's/.*\//Tag: /' printf " " ls "$x" --sort=time | tail -n 1 echo done ;;
help) ## this message show_help ;;
*) echo Bad DB command: $1 show_help ;; esac</lang> Sample usage (assuming script is named "sdb"):<lang>$ sdb create CDs Create DB `CDs' $ sdb add CDs Bookends $ sdb prop CDs Bookends artists "Simon & Garfunkel" $ sdb add CDs "Ode to joy" $ sdb prop CDs "Ode to joy" artist "Beethoven" $ sdb tag CDs Bookends rock folk # I'm not sure about this $ sdb tag CDs "Ode to joy" classical $ sdb show CDs Bookends Description:
artists:
Simon & Garfunkel
Tags: folk rock $ sdb prop CDs "Ode to joy" Description "Sym. No. 9" $ sdb show CDs "Ode to joy" Description:
Sym. No. 9
artist:
Beethoven
Tags: classical $ sdb last-all CDs Tag: classical
Ode to joy
Tag: folk
Bookends
Tag: rock
Bookends
$ sdb drop CDs Delete DB `CDs' $</lang>