CloudFlare suffered a massive security issue affecting all of its customers, including Rosetta Code. All passwords not changed since February 19th 2017 have been expired, and session cookie longevity will be reduced until late March.--Michael Mol (talk) 05:15, 25 February 2017 (UTC)

Simple database

From Rosetta Code
Task
Simple database
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[edit]

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':

  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)
)
)
);
 

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[edit]

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" 
#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);
}

COBOL[edit]

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.

Works with: OpenCOBOL
       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."
.

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[edit]

This example is incorrect. Please fix the code and remove this message.
Details: "add" operation fails to create database if it doesn't exist.

A tool to track the episodes you have watched in a series. Tested with SBCL but should work with other implementations.

Run from the commandline as:

sbcl --script watch.lisp

Without arguments the function (watch-list) is invoked to show the last episode of each series. With the argument add the function (watch-add) will allow you to add a new episode with series name, episode title, episode number and date watched. If the series does not yet exist, you will be asked if you want to create it.

This code is also available under the GNU GPLv3.

(defvar *db* nil)
 
(defstruct series description tags episodes)
 
(defstruct (episode (:print-function print-episode-struct))
series title season episode part date tags)
 
(defun format-ymd (date)
(format nil "~{~a.~a.~a~}" date))
 
(defun print-episode-struct (ep stream level)
(let ((*print-pretty* nil))
(format stream (if *print-escape*
"#s(episode~@{~*~@[ :~1:*~a ~s~]~})"
"~32<~*~a~; ~*~@[~d-~]~*~d~> ~45<~*~@[~a ~]~*~@[(~a) ~]~;~*~@[(~a)~]~>~*~@[ (~{~a~^ ~})~]")
:series (episode-series ep)
:season (episode-season ep)
:episode (episode-episode ep)
:title (episode-title ep)
:part (episode-part ep)
:date (if *print-escape*
(episode-date ep)
(when (episode-date ep)
(format-ymd (episode-date ep))))
:tags (episode-tags ep))))
 
(defun get-value (key alist)
(cdr (assoc key alist)))
 
 
(defun get-latest (database)
(when database
(cons (car (series-episodes (cdar database))) (get-latest (cdr database)))))
 
(defun get-all (database)
(when database
(append (series-episodes (cdar database)) (get-all (cdr database)))))
 
(defun compare-date (a b)
(cond ((not a) t)
((not b) nil)
((= (first a) (first b))
(compare-date (rest a) (rest b)))
(t (< (first a) (first b)))))
 
(defun compare-by-date (a b)
(compare-date (episode-date a) (episode-date b)))
 
(defun prompt-read (prompt &optional default)
(format *query-io* "~a~@[ (~a)~]: " prompt default)
(force-output *query-io*)
(let ((answer (read-line *query-io*)))
(if (string= answer "")
default
answer)))
 
(defun split (seperator string)
(loop for i = 0 then (1+ j)
as j = (search seperator string :start2 i)
collect (subseq string i j)
while j))
 
(defun get-current-date ()
(multiple-value-bind
(second minute hour date month year day-of-week dst-p tz)
(get-decoded-time)
(declare (ignore second minute hour day-of-week dst-p tz))
(list date month year)))
 
 
(defun parse-date (date)
(reverse (mapcar #'parse-integer (split "." date))))
 
(defun parse-tags (tags)
(when (and tags (string-not-equal "" tags))
(mapcar #'intern (split " " (string-upcase tags)))))
 
(defun parse-number (number)
(if (stringp number)
(parse-integer number :junk-allowed t)
number))
 
(defun prompt-for-episode (&optional last)
(when (not last)
(setf last (make-episode)))
(let* ((series (prompt-read "Series Title" (episode-series last)))
(title (prompt-read "Title"))
(season (parse-number (prompt-read "Season" (episode-season last))))
(episode (parse-number (prompt-read "Episode"
(if (eq (episode-season last) season)
(1+ (episode-episode last))
1))))
(part (parse-number (prompt-read "Part"
(when (and (episode-part last)
(or (eq (episode-season last) season)
(eq (episode-part last) 1)))
(1+ (episode-part last))))))
(date (parse-date (prompt-read "Date watched" (format-ymd (get-current-date)))))
(tags (parse-tags (prompt-read "Tags"))))
(make-episode
:series series
:title title
:season season
:episode episode
:part part
:date date
:tags tags)))
 
(defun parse-integer-quietly (&rest args)
(ignore-errors (apply #'parse-integer args)))
 
(defun get-next-version (basename)
(flet ((parse-version (pathname)
(or (parse-integer-quietly
(string-left-trim (file-namestring basename)
(file-namestring pathname))
:start 1) 0)))
(let* ((files (directory (format nil "~A,*" (namestring basename))))
(max (if files
(reduce #'max files :key #'parse-version)
0)))
(merge-pathnames (format nil "~a,~d" (file-namestring basename) (1+ max))
basename))))
 
(defun save-db (dbfile database)
(let ((file (probe-file dbfile)))
(rename-file file (get-next-version file))
(with-open-file (out file :direction :output)
(with-standard-io-syntax
(let ((*print-case* :downcase))
(pprint database out))))))
 
(defun watch-save (dbfile)
(save-db dbfile *db*))
 
(defun load-db (dbfile)
(with-open-file (in dbfile)
(with-standard-io-syntax
(read in))))
 
(defun get-series (name database)
(cdr (assoc name database :test #'string-equal)))
 
(defun get-episode-list (series database)
(series-episodes (get-series series database)))
 
(defun print-series (title series)
(format t "~&~30a ~@[ (~{~a~^ ~})~]~%~@[ ~a~%~]" title (series-tags series)
(series-description series))
(format t "~{~& ~a~%~}" (reverse (series-episodes series))))
 
(defun watch-series (title)
(let ((series (get-series title *db*)))
(when series
(print-series title series))))
 
(defun print-all-series (database)
(loop for (title . series)
in (sort database #'(lambda (a b)(compare-by-date (car (series-episodes (cdr a)))
(car (series-episodes (cdr b))))))
do (terpri) (print-series title series)))
 
(defun watch-all-series ()
(print-all-series *db*))
 
(defun watch-latest ()
(format t "~{~& ~a~%~}" (sort (get-latest *db*) #'compare-by-date)))
 
(defun timeline-all (database)
(let* ((all (get-all database))
(max (length all))
(count max)
(all-series-names nil)
(all-series (make-hash-table :test 'equal)))
(loop for episode in (reverse (sort all #'compare-by-date))
do (unless (gethash (episode-series episode) all-series)
(setf (gethash (episode-series episode) all-series)
(make-array max :initial-element nil))
(setf all-series-names
(cons (episode-series episode) all-series-names)))
(setf (elt (gethash (episode-series episode) all-series) (decf count))
episode))
(values all-series all-series-names max)))
 
(defun watch-timeline ()
(multiple-value-bind (all-series all-series-names max) (timeline-all *db*)
(loop for series in all-series-names
do (format t "~30a (~{~:[ ~;•~]~})~%" series
(coerce (subseq (gethash series all-series) (- max 60)) 'list)))))
 
(defun watch-timelinec ()
(multiple-value-bind (all-series all-series-names max) (timeline-all *db*)
(let ((chart (make-array (list (length all-series-names) max) :initial-element nil))
(newcol 0)
(oldrow -1))
(loop for oldcol upto (1- max)
do (loop for series in all-series-names
for row from 0 upto (length all-series-names)
do (when (elt (gethash series all-series) oldcol)
(when (<= row oldrow)
(incf newcol))
(setf (aref chart row newcol)
(elt (gethash series all-series) oldcol))
(setf oldrow row))))
(loop for series in all-series-names
for i from 0 upto (length all-series-names)
do (format t "~30a (" series)
(loop for j from (- newcol 60) upto newcol
do (format t "~:[ ~;•~]" (aref chart i j))
(if (= j newcol)
(format t ")~%")))))))
 
(defun watch-timelinev ()
(multiple-value-bind (all-series all-series-names max) (timeline-all *db*)
(loop for series in all-series-names
counting series into count
do (format t "~va ~30a~%" count " " series ))
(loop for i from 0 upto (1- max)
do (let ((episode nil))
(loop for series in all-series-names
do (format t "~:[ ~;~:*~02a~]"
(when (elt (gethash series all-series) i)
(setf episode (elt (gethash series all-series) i))
(episode-episode episode))))
(format t " (~a)~%" (episode-series episode))))))
 
(defun watch-all ()
(format t "~{~& ~a~%~}" (sort (get-all *db*) #'compare-by-date)))
 
(defun watch-new-series (&key name description tags)
(cdar (push (cons name (make-series :description description :tags tags)) *db*)))
 
(defun get-or-add-series (name database)
(or (get-series name database)
(if (y-or-n-p "Add new series? [y/n]: ")
(watch-new-series
:name name
:description (prompt-read "Description" name)
:tags (parse-tags (prompt-read "Tags" "active")))
nil)))
 
(defun watch-add ()
(let* ((series (loop thereis (get-or-add-series (prompt-read "Series") *db*)))
(episode (prompt-for-episode (car (series-episodes series)))))
(push episode (series-episodes series))))
 
(defun watch-series-names ()
(format T "~{~& ~a~%~}"
(sort (mapcar #'car *db*)
(lambda (series1 series2)
(compare-by-date (car (series-episodes (get-value series1 *db*)))
(car (series-episodes (get-value series2 *db*))))))))
 
(defun exact-match (term text)
(string-equal (format nil "~{~a~^ ~}" term) text))
 
(defun fuzzy-match (term text)
(loop for word in term
when (search word text :test 'string-equal)
collect it))
 
(defun match-tags (term tags)
(intersection (mapcar #'intern term) tags))
 
(defun search-title (term database)
(loop for episode in (get-all database)
when (exact-match term (episode-title episode))
collect episode))
 
(defun search-tags (term database)
(sort (loop for episode in (get-all database)
for matches = (match-tags term (episode-tags episode))
when matches collect (list (length matches) episode))
#'> :key #'car))
 
(defun search-title-fuzzy (term database)
(sort (loop for episode in (get-all database)
for matches = (fuzzy-match term (episode-title episode))
when matches collect (list (length matches) episode))
#'> :key #'car))
 
(defun search-all (term database)
(let ((exact-results '())
(fuzzy-results '())
(tag-results '()))
(dolist (episode (get-all database))
(cond ((exact-match term (episode-title episode))
(push episode exact-results))
((fuzzy-match term (episode-title episode))
(push episode fuzzy-results))
((match-tags term (episode-tags episode))
(push episode tag-results))))
(append (sort exact-results #'compare-by-date)
(sort tag-results #'compare-by-date)
(sort fuzzy-results #'compare-by-date))))
 
(defun watch-search (term)
(format t "~{~& ~a~%~}" (search-all term *db*)))
 
(defun list-all-tags (database)
(let ((tags (make-hash-table :test 'equal)))
(dolist (tag (apply #'append (mapcar #'episode-tags (get-all database))))
(setf (gethash tag tags) (1+ (or (gethash tag tags) 0))))
tags))
 
(defun watch-tags ()
(maphash #'(lambda (tag count) (format t "~a (~d) " tag count))
(list-all-tags *db*))
(terpri))
 
(defun find-series-episode (term database)
(let ((series (get-series (format nil "~{~a~^ ~}" (butlast term)) database)))
(if series
(let* ((season-episode (car (last term)))
(pos (position #\- season-episode))
(season-str (when pos (subseq season-episode 0 pos)))
(season (or (parse-integer-quietly season-str) season-str))
(episode-str (if pos
(subseq season-episode (1+ pos))
season-episode))
(episode-nr (or (parse-integer-quietly episode-str) episode-str)))
(loop for episode in (series-episodes series)
when (and (equal (episode-episode episode) episode-nr)
(equal (episode-season episode) season))
collect episode))
(let ((series (get-series (format nil "~{~a~^ ~}" term) database)))
(if series
(list (car (series-episodes series))))))))
 
 
(defun find-episode (term database)
(or (find-series-episode term database)
(search-title term database)
(let* ((res (or (search-tags term database)
(search-title-fuzzy term database)))
(max (caar res)))
(loop for (matches episode) in res when (equal matches max) collect episode))))
 
(defun edit-episode (episode database)
(format t "editing:~%~a~%" episode)
(setf (episode-series episode)
(prompt-read "Series Title" (episode-series episode)))
(setf (episode-title episode)
(prompt-read "Title" (episode-title episode)))
(setf (episode-season episode)
(parse-number (prompt-read "Season" (episode-season episode))))
(setf (episode-episode episode)
(parse-number (prompt-read "Episode" (episode-episode episode))))
(setf (episode-part episode)
(parse-number (prompt-read "Part" (episode-part episode))))
(setf (episode-date episode)
(parse-date (prompt-read "Date watched" (format-ymd (episode-date episode)))))
(setf (episode-tags episode)
(parse-tags (prompt-read "Tags" (format nil "~{~a~^ ~}" (episode-tags episode))))))
 
(defun watch-edit (term)
(let ((episodes (find-episode term *db*)))
(if (> (length episodes) 1)
(format t "found more than one episode, please be more specific:~%~{~& ~a~%~}" episodes)
(edit-episode (car episodes) *db*))))
 
(defun watch-load (dbfile)
(setf *db* (load-db dbfile)))
 
 
(defun argv ()
(or
#+clisp (ext:argv)
#+sbcl sb-ext:*posix-argv*
#+clozure (ccl::command-line-arguments)
#+gcl si:*command-args*
#+ecl (loop for i from 0 below (si:argc) collect (si:argv i))
#+cmu extensions:*command-line-strings*
#+allegro (sys:command-line-arguments)
#+lispworks sys:*line-arguments-list*
nil))
 
(defun main (argv)
(let ((dbfile (make-pathname :name "lwatch" :type nil :defaults *load-pathname*)))
(watch-load dbfile)
(format t "loaded db~%")
(cond ((equal (cadr argv) "add") (watch-add) (watch-save dbfile))
((equal (cadr argv) "latest") (watch-latest))
((null (cadr argv)) (watch-latest))
((equal (cadr argv) "series") (watch-series-names))
((and (equal (cadr argv) "all") (equal (caddr argv) "series")) (watch-all-series))
((equal (cadr argv) "all") (watch-all))
((equal (cadr argv) "tags") (watch-tags))
((equal (cadr argv) "search") (watch-search (cddr argv)))
((equal (cadr argv) "edit") (watch-edit (cddr argv)) (watch-save dbfile))
((equal (cadr argv) "timeline") (watch-timeline))
((equal (cadr argv) "timelinev") (watch-timelinev))
((equal (cadr argv) "timelinec") (watch-timelinec))
(T (watch-series (format nil "~{~a~^ ~}" (cdr argv)))))))
 
(main (argv))

D[edit]

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;
}
}
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[edit]

 
#! /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() ->
{{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().
 

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[edit]

Simple in-memory database. Load/dump database from/to a file.

Works with: Gforth version 0.7

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:

\ 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

Go[edit]

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)
}
}

Haskell[edit]

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"]}

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
 

J[edit]

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:

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';'';'li''st';'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
 

Assume the j code is stored in file s . These bash commands, stored in file input , create a database using add .

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 [email protected] y' 'f(g(y))' 'rank of g' monad '*:@(+/)' 'square the sum'
$D add atop 'x [email protected] y' 'f(g(x,y))' 'rank of g' dyad '>@{.' '(lisp) open the car'
$D add 'many more!'
 

Now we look up data from the bash command line.

 
$ . 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 [email protected] 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 [email protected] 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 [email protected] y │f(g(y)) │rank of g │monad │*:@(+/) │square the sum │
│2012-02-08:23:45:06.515│atop │x [email protected] 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';[email protected] y';'f(g(y))';'rank of g';'monad';'*:@(+/)';'square the sum'
'2012-02-08:23:45:06.515';'atop';'x [email protected] y';'f(g(x,y))';'rank of g';'dyad';'>@{.';'(lisp) open the car'
'2012-02-08:23:45:06.539';'many more!'
$

Java[edit]

Translation of: D
Works with: Java version 7
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\"");
}
}

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

Phix[edit]

--
-- 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

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[edit]

The 'rc' resource file handling function is used typically for such tasks. It also takes care of proper locking and protection.

#!/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)

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[edit]

Translation of: Common Lisp
(simplified)
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);
}

PowerShell[edit]

 
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
 

Here is the data from the CSV file as a PowerShell Object:

 
db
 
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:

 
db -Latest
 
Output:
Name  Category Birthday             
----  -------- --------             
Wayne coworker 5/29/1962 12:00:00 AM

The latest entries by category:

 
db -LatestByCategory
 
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:

 
db -SortedByDate
 
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[edit]

#!/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)
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[edit]

 
#!/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")])])
 

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[edit]

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

REXX[edit]

/* 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
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[edit]

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 [email protected] 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 = "[email protected]}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

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[edit]

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 "<TABLE BORDER=1 CELLPADDING=0 CELLSPACING=0 bgcolor=wheat>"
html "<TR align=center BGCOLOR=tan><TD colspan=2>Client Maintenance</TD></TR><TR>"
html "<TD bgcolor=tan align=right>Client Num</TD><TD>"
textbox #clientNum,clientNum$,5
 
html "</TD></TR><TR><TD bgcolor=tan align=right>Name</TD><TD>"
textbox #name,name$,30
 
html "</TD></TR><TR><TD bgcolor=tan align=right>Client Date</TD><TD>"
textbox #clientDate,clientDate$,19
 
html "</TD></TR><TR><TD bgcolor=tan align=right>Category</TD><TD>"
textbox #category,category$,10
 
html "</TD></TR><TR><TR bgcolor=tan><TD colspan=2 ALIGN=CENTER>"
button #acd, "Add", [addIt]
button #ex, "Exit", [sho]
html "</TD></TR></TABLE>"
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 "<TABLE BORDER=1 CELLPADDING=0 CELLSPACING=0>"
html "<TR align=center bgcolor=wheat><TD>Client<br>Num</TD><TD>Name</TD><TD>Client<br>Date</TD><TD>Category</TD></TR>" ' heading
#sql execute(sql$)
WHILE #sql hasanswer()
#row = #sql #nextrow()
clientNum = #row clientNum()
name$ = #row name$()
clientDate$ = #row clientDate$()
category$ = #row category$()
 
html "<TR><TD align=right>";clientNum;"</TD><TD>";name$;"</TD><TD>";clientDate$;"</TD><TD>";category$;"</TD></TR>"
WEND
html "</TABLE>"
button #c, "Continue", [sho]
wait
 
' ------ the end -------
[exit]
end

Output:


User Input ----
Client Maintenance
Client Num5
NameDawnridge Winery
Client Date2008-06-18 22:16
Categorywine
[Add] [Exit]

Last Entry ----
Client
Num
NameClient
Date
Category
5Dawnridge Winery2008-06-18 22:16wine

Last category Sequence ----
Client
Num
NameClient
Date
Category
1Home Sales2012-01-01 10;20broker
4Back 40 Equipment2009-09-18 20:18farm
3Floral Designs2010-10-14 09:16flowers
2Best Foods2011-02-02 12:33food
5Dawnridge Winery2008-06-18 22:16wine

Date Sequence ----
Client
Num
NameClient
Date
Category
5Dawnridge Winery2008-06-18 22;16wine
4Back 40 Equipment2009-09-18 20:18farm
3Floral Designs2010-10-14 09:16flowers
2Best Foods2011-02-02 12:33food
1Home Sales2012-01-01 10:20broker

Scala[edit]

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]...]]]")
}
}
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[edit]

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.

#!/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 $xtra]
}
proc latest {{category ""}} {
variable db
if {$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]

Sample session:

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

ToffeeScript[edit]

#!/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

UNIX Shell[edit]

This format is guaranteed to be human readable: if you can type it, you can read it.

#!/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
Sample usage (assuming script is named "sdb"):
$ 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'
$