Readline interface: Difference between revisions

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→‎{{header|Wren}}: Changed to Wren S/H
(→‎{{header|REXX}}: reduced the size of the program, added more commands. -- ~~~~)
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{{draft task|TerminalReadline controlinterface}}
 
A readline interface is a line editing facility that provides auto completion facilities and the ability to recall previously typed lines. Build a simple application withthat accepts at least two commands and uses a readline style interface.
 
The interface should provide
 
* the ability to recall previously typed commands
* a history
* commandline editing
* application specific commands
Line 16:
 
__TOC__
 
=={{header|11l}}==
{{trans|D}}
 
<syntaxhighlight lang="11l">[String] histArr
 
F hello()
print(‘Hello World!’)
:histArr [+]= ‘hello’
 
F hist()
I :histArr.empty
print(‘No history’)
E
L(cmd) :histArr
print(‘ - ’cmd)
:histArr [+]= ‘hist’
 
F help()
print(‘Available commands:’)
print(‘ hello’)
print(‘ hist’)
print(‘ exit’)
print(‘ help’)
:histArr [+]= ‘help’
 
[String = (() -> N)] aa
aa[‘help’] = help
aa[‘hist’] = hist
aa[‘hello’] = hello
 
print(‘Enter a command, type help for a listing.’)
 
L
V line = input(‘>’)
I line == ‘exit’
L.break
aa.get(line, help)()</syntaxhighlight>
 
=={{header|C}}==
A program that does absolutely nothing. Type 'help' for help.
<langsyntaxhighlight lang="c">#include <readline/readline.h>
#include <readline/history.h>
#include <string.h>
Line 43 ⟶ 81:
puts("Yes...?");
}
}</langsyntaxhighlight>
 
=={{header|C sharp|C#}}==
{{trans|D}}
<syntaxhighlight lang="csharp">using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
 
namespace ReadlineInterface {
class Program {
static LinkedList<string> histArr = new LinkedList<string>();
 
static void AppendHistory([CallerMemberName] string name = "unknown") {
histArr.AddLast(name);
}
 
static void Hist() {
if (histArr.Count == 0) {
Console.WriteLine("No history");
}
else {
foreach (string cmd in histArr) {
Console.WriteLine(" - {0}", cmd);
}
}
AppendHistory();
}
 
static void Hello() {
Console.WriteLine("Hello World!");
AppendHistory();
}
 
static void Help() {
Console.WriteLine("Available commands:");
Console.WriteLine(" hello");
Console.WriteLine(" hist");
Console.WriteLine(" exit");
Console.WriteLine(" help");
AppendHistory();
}
 
static void Main(string[] args) {
Dictionary<string, Action> cmdDict = new Dictionary<string, Action>();
cmdDict.Add("help", Help);
cmdDict.Add("hist", Hist);
cmdDict.Add("hello", Hello);
 
Console.WriteLine("Enter a command, type help for a listing.");
while (true) {
Console.Write(">");
string line = Console.ReadLine();
if (line=="exit") {
break;
}
 
Action action;
if (cmdDict.TryGetValue(line, out action)) {
action.Invoke();
} else {
Help();
}
}
}
}
}</syntaxhighlight>
 
=={{header|C++}}==
{{trans|D}}
<syntaxhighlight lang="cpp">#include <iostream>
#include <string>
#include <vector>
 
std::vector<std::string> hist;
 
std::ostream& operator<<(std::ostream& os, const std::string& str) {
return os << str.c_str();
}
 
void appendHistory(const std::string& name) {
hist.push_back(name);
}
 
void hello() {
std::cout << "Hello World!\n";
appendHistory(__func__);
}
 
void history() {
if (hist.size() == 0) {
std::cout << "No history\n";
} else {
for (auto& str : hist) {
std::cout << " - " << str << '\n';
}
}
appendHistory(__func__);
}
 
void help() {
std::cout << "Available commands:\n";
std::cout << " hello\n";
std::cout << " hist\n";
std::cout << " exit\n";
std::cout << " help\n";
appendHistory(__func__);
}
 
int main() {
bool done = false;
std::string cmd;
 
do {
std::cout << "Enter a command, type help for a listing.\n";
std::cin >> cmd;
for (size_t i = 0; i < cmd.size(); ++i) {
cmd[i] = toupper(cmd[i]);
}
 
if (strcmp(cmd.c_str(), "HELLO") == 0) {
hello();
} else if (strcmp(cmd.c_str(), "HIST") == 0) {
history();
} else if (strcmp(cmd.c_str(), "EXIT") == 0) {
done = true;
} else {
help();
}
} while (!done);
 
return 0;
}</syntaxhighlight>
 
=={{header|D}}==
<syntaxhighlight lang="d">module readline_interface;
 
import std.stdio;
import std.string;
 
alias VOIDF = void function();
 
void hello() {
writeln("Hello World!");
histArr ~= __FUNCTION__;
}
 
string[] histArr;
void hist() {
if (histArr.length == 0) {
writeln("No history");
} else {
foreach(cmd; histArr) {
writeln(" - ", cmd);
}
}
histArr ~= __FUNCTION__;
}
 
void help() {
writeln("Available commands:");
writeln(" hello");
writeln(" hist");
writeln(" exit");
writeln(" help");
histArr ~= __FUNCTION__;
}
 
void main() {
VOIDF[string] aa;
aa["help"] = &help;
aa["hist"] = &hist;
aa["hello"] = &hello;
 
writeln("Enter a command, type help for a listing.");
 
string line;
 
write(">");
while ((line = readln()) !is null) {
line = chomp(line);
if (line == "exit") {
break;
}
aa.get(line, &help)();
write(">");
}
}</syntaxhighlight>
{{out}}
<pre>Enter a command, type help for a listing.
>hist
No history
>help
Available commands:
hello
hist
exit
help
>hello
Hello World!
>hist
- readline_interface.hist
- readline_interface.help
- readline_interface.hello
>exit</pre>
 
=={{header|Go}}==
{{trans|D}}
<syntaxhighlight lang="go">package main
 
import (
"bufio"
"fmt"
"log"
"os"
"strings"
)
 
type vf = func()
 
var history []string
 
func hello() {
fmt.Println("Hello World!")
history = append(history, "hello")
}
 
func hist() {
if len(history) == 0 {
fmt.Println("No history")
} else {
for _, cmd := range history {
fmt.Println(" -", cmd)
}
}
history = append(history, "hist")
}
 
func help() {
fmt.Println("Available commands:")
fmt.Println(" hello")
fmt.Println(" hist")
fmt.Println(" exit")
fmt.Println(" help")
history = append(history, "help")
}
 
func main() {
scanner := bufio.NewScanner(os.Stdin)
vfs := map[string]vf{"help": help, "hist": hist, "hello": hello}
fmt.Println("Enter a command, type help for a listing.")
for {
fmt.Print(">")
scanner.Scan()
if scerr := scanner.Err(); scerr != nil {
log.Fatal(scerr)
}
line := strings.TrimSpace(scanner.Text())
if line == "exit" {
return
}
cmd, ok := vfs[line]
if !ok {
fmt.Println("Unknown command, try again")
} else {
cmd()
}
}
}</syntaxhighlight>
 
{{out}}
Sample session:
<pre>
Enter a command, type help for a listing.
>hit
Unknown command, try again
>hist
No history
>help
Available commands:
hello
hist
exit
help
>hello
Hello World!
>hist
- hist
- help
- hello
>exit
</pre>
 
=={{header|Java}}==
{{trans|C#}}
<syntaxhighlight lang="java">import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
 
public class ReadlineInterface {
private static LinkedList<String> histArr = new LinkedList<>();
 
private static void hist() {
if (histArr.isEmpty()) {
System.out.println("No history");
} else {
histArr.forEach(cmd -> System.out.printf(" - %s\n", cmd));
}
 
class Crutch {}
histArr.add(Crutch.class.getEnclosingMethod().getName());
}
 
private static void hello() {
System.out.println("Hello World!");
 
class Crutch {}
histArr.add(Crutch.class.getEnclosingMethod().getName());
}
 
private static void help() {
System.out.println("Available commands:");
System.out.println(" hello");
System.out.println(" hist");
System.out.println(" exit");
System.out.println(" help");
 
class Crutch {}
histArr.add(Crutch.class.getEnclosingMethod().getName());
}
 
public static void main(String[] args) throws IOException {
Map<String, Runnable> cmdMap = new HashMap<>();
cmdMap.put("help", ReadlineInterface::help);
cmdMap.put("hist", ReadlineInterface::hist);
cmdMap.put("hello", ReadlineInterface::hello);
 
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
 
System.out.println("Enter a command, type help for a listing.");
while (true) {
System.out.print(">");
String line = in.readLine();
if ("exit".equals(line)) {
break;
}
 
cmdMap.getOrDefault(line, ReadlineInterface::help).run();
}
}
}</syntaxhighlight>
 
=={{header|Julia}}==
{{works with|Julia|0.6}}
 
Simple program that does nothing (copy of [[#C | C]]).
 
<syntaxhighlight lang="julia">function input(prompt::AbstractString)
print(prompt)
r = readline(STDIN)
 
if isempty(r) || r == "quit"
println("bye.")
elseif r == "help"
println("commands: ls, cat, quit")
elseif r ∈ ("ls", "cat")
println("command `$r` not implemented yet")
else
println("Yes...?")
end
end
 
input("This is a common prompt> ")</syntaxhighlight>
 
=={{header|Kotlin}}==
<syntaxhighlight lang="scala">// version 1.0.6
 
var range = intArrayOf() // empty initially
val history = mutableListOf<String>()
 
fun greeting() {
ProcessBuilder("cmd", "/c", "cls").inheritIO().start().waitFor() // clears console in windows 10
println("** Welcome to the Ranger readline interface **")
println("** which performs operations on a range of integers **\n")
println("Commands available:")
println(" range [i] [j], help, show, square, cube, add [n], sub [n]")
println(" mul [n], prev, hist, quit")
println()
}
 
fun setRange(start: Int, end: Int) {
range = IntArray(end - start + 1) { it + start }
show()
}
 
fun help() {
println(" range [i] [j] - sets the current range to [i, j] and shows them")
println(" - if i > j, sets the current range to the single value [i]")
println(" help - displays help for each command")
println(" show - displays a maximum of 10 values from the current range")
println(" square - sets the current range to their squares and shows them")
println(" cube - sets the current range to their cubes and shows them")
println(" add [i] - adds [i] to the current range and shows them")
println(" sub [i] - subtracts [i] from the current range and shows them")
println(" mul [i] - multiplies the current range by [i] and shows them")
println(" prev - displays previous command entered")
println(" hist - displays a maximum of last 10 commands entered, newest first")
println(" quit - quits Ranger")
println()
println(" < items in square brackets denote integers to be supplied e.g. range 1 5 >")
println(" < right/left arrow keys can be used to scroll through previous commands >")
}
 
fun show() {
val max = if (range.size > 10) 10 else range.size
val more = range.size - max
for (i in 0 until max) println(" ${range[i]}")
if (more > 0) println(" plus $more more")
}
 
fun square() {
for (i in 0 until range.size) range[i] *= range[i]
show()
}
 
fun cube() {
for (i in 0 until range.size) range[i] *= range[i] * range[i]
show()
}
 
fun add(n: Int) {
for (i in 0 until range.size) range[i] += n
show()
}
 
fun sub(n: Int) {
for (i in 0 until range.size) range[i] -= n
show()
}
 
fun mul(n: Int) {
for (i in 0 until range.size) range[i] *= n
show()
}
 
fun prev() {
if (history.size == 0) println("- No history yet") else println("- ${history.last()}")
}
 
fun showHistory() {
val size = history.size
if (size == 0) {println("- No history yet"); return}
val max = if (size > 10) 10 else size
val more = size - max
for (i in size - 1 downTo size - max) println("- ${history[i]}")
if (more > 0) println("- plus $more more")
}
 
fun main(args: Array<String>) {
val r = Regex ("\\s+")
val rangeCommands = arrayOf("show", "square", "cube", "add", "sub", "mul")
greeting()
while (true) {
var command = readLine()!!.trim().toLowerCase()
if (command == "") continue
var i: Int = 0
var j: Int = 0
var addToHistory = true
 
if (command.startsWith("range")) {
if (command == "range") { println("- Parameters required, try again\n"); continue}
val splits = command.split(r)
if (splits.size == 3) {
try {
i = splits[1].toInt()
j = splits[2].toInt()
if (i > j) j = i
command = "range"
history.add("$command $i $j")
addToHistory = false
}
catch(ex: NumberFormatException) {
}
}
}
else if (command.startsWith("add") || command.startsWith("sub") || command.startsWith("mul")) {
if (command.length == 3) { println("- Parameter required, try again\n"); continue}
val splits2 = command.split(r)
if (splits2.size == 2) {
try {
i = splits2[1].toInt()
command = command.take(3)
history.add("$command $i")
addToHistory = false
}
catch(ex: NumberFormatException) {
}
}
}
 
if (range.size == 0 && command in rangeCommands) {
println("- Range has not yet been set\n")
if (addToHistory) history.add(command)
continue
}
when (command) {
"range" -> setRange(i, j)
"help" -> help()
"show" -> show()
"square" -> square()
"cube" -> cube()
"add" -> add(i)
"sub" -> sub(i)
"mul" -> mul(i)
"prev" -> prev()
"hist" -> showHistory()
"quit" -> return
else -> {addToHistory = false; println("- Invalid command, try again")}
}
 
if (addToHistory) history.add(command)
println()
}
}</syntaxhighlight>
 
{{out}}
<pre>
** Welcome to the Ranger readline interface **
** which performs operations on a range of integers **
 
Commands available:
range [i] [j], help, show, square, cube, add [n], sub [n]
mul [n], prev, hist, quit
 
help
range [i] [j] - sets the current range to [i, j] and shows them
- if i > j, sets the current range to the single value [i]
help - displays help for each command
show - displays a maximum of 10 values from the current range
square - sets the current range to their squares and shows them
cube - sets the current range to their cubes and shows them
add [i] - adds [i] to the current range and shows them
sub [i] - subtracts [i] from the current range and shows them
mul [i] - multiplies the current range by [i] and shows them
prev - displays previous command entered
hist - displays a maximum of last 10 commands entered, newest first
quit - quits Ranger
 
< items in square brackets denote integers to be supplied e.g. range 1 5 >
< right/left arrow keys can be used to scroll through previous commands >
 
range 1 3
1
2
3
 
add 1
2
3
4
 
mul 2
4
6
8
 
sub 3
1
3
5
 
square
1
9
25
 
cube
1
729
15625
 
hist
- cube
- square
- sub 3
- mul 2
- add 1
- range 1 3
- help
 
prev
- hist
 
show
1
729
15625
 
quit
</pre>
 
=={{header|Nim}}==
{{trans|Go}}
Nim provides a module <code>rdstdin</code> to read form standard input file. This modules provides navigation in history of previous commands using the up and down keys.
 
<syntaxhighlight lang="nim">import rdstdin, strutils, tables
 
var history: seq[string]
 
proc hello =
echo "Hello World!"
history.add "hello"
 
proc hist =
if history.len == 0:
echo "no history"
else:
for cmd in history:
echo " -", cmd
history.add "hist"
 
proc help =
echo "Available commands:"
echo " hello"
echo " hist"
echo " exit"
echo " help"
history.add "help"
 
const Vfs = {"help": help, "hist": hist, "hello": hello}.toTable
 
echo "Enter a command, type help for a listing."
while true:
let line = try:
readLineFromStdin(">").strip()
except IOError:
echo "EOF encountered. Bye."
break
if line == "exit": break
if line notin Vfs:
echo "Unknown command, try again."
else:
Vfs[line]()</syntaxhighlight>
 
{{out}}
Sample session.
<pre>Enter a command, type help for a listing.
>help
Available commands:
hello
hist
exit
help
>hello
Hello World!
>hist
-help
-hello
>quit
Unknown command, try again.
>exit</pre>
 
=={{header|PARI/GP}}==
 
gp uses readline, but it can also be used directly in PARI:
 
<syntaxhighlight lang="c">#include <stdio.h>
#include <pari/pari.h>
#include <readline/readline.h>
#include <setjmp.h>
 
jmp_buf env;
void gp_err_recover(long numerr) { longjmp(env, numerr); }
 
/* History handling (%1, %2, etc.)*/
pari_stack s_history;
GEN *history;
GEN parihist(long p)
{
if (p > 0 && p<=s_history.n)
return history[p-1];
else if (p<=0 && s_history.n+p-1>=0)
return history[s_history.n+p-1];
pari_err(talker,"History result %ld not available [%%1-%%%ld]",p,s_history.n);
return NULL; /* not reached */
}
 
int main(int argc, char **argv)
{
char *in, *out;
GEN z;
entree hist={"%",0,(void*)parihist,13,"D0,L,","last history item."};
printf("Welcome to minigp!\n");
pari_init(8000000,500000);
cb_pari_err_recover = gp_err_recover;
pari_add_function(&hist);
stack_init(&s_history,sizeof(*history),(void**)&history);
(void)setjmp(env);
while(1)
{
in = readline("? ");
if (!in) break;
if (!*in) continue;
z = gp_read_str(in);
stack_pushp(&s_history,(void*)gclone(z)); /*Add to history */
out = GENtostr(z);
printf("%%%ld = %s\n",s_history.n,out);
free(in); free(out); avma=top;
}
return 0;
}</syntaxhighlight>
 
<small>Code thanks to [http://pari.math.u-bordeaux.fr/archives/pari-dev-1002/msg00023.html Bill Allombert]</small>
 
=={{header|Perl}}==
A Perl shell with command history, line-editing and variable-name completion. Simplified from the example supplied with the CPAN module <code>Term::Readline::Gnu</code>.
<syntaxhighlight lang="perl">use strict;
use warnings;
use Term::ReadLine;
use POSIX;
 
my $term = Term::ReadLine->new( 'simple Perl shell' );
my $attribs = $term->Attribs;
$attribs->{completion_append_character} = ' ';
$attribs->{attempted_completion_function} = \&attempt_perl_completion;
$attribs->{completion_display_matches_hook} = \&perl_symbol_display_match_list;
 
while (defined(my $command = &reader)) {
my @result = eval ("package main; $command");
print "$_\n" for @result;
}
 
sub reader {
my $command = $term->readline('> ');
$term->addhistory($command) if $command;
$command;
}
 
sub perl_symbol_display_match_list {
my($matches, $num_matches, $max_length) = @_;
map { $_ =~ s/^((\$#|[\@\$%&])?).*::(.+)/$3/; }(@{$matches});
$term->display_match_list($matches);
$term->forced_update_display;
}
 
sub attempt_perl_completion {
my ($text, $line, $start, $end) = @_;
$term->completion_matches($text, \&perl_symbol_completion_function);
}
 
use vars qw($i @matches $prefix);
sub perl_symbol_completion_function {
my($text, $state) = @_;
my %type = ('$' => 'SCALAR', '*' => 'SCALAR', '@' => 'ARRAY', '$#' => 'ARRAY', '%' => 'HASH', '&' => 'CODE');
 
if ($state) {
$i++;
} else {
my ($pre, $pkg, $sym);
$i = 0;
 
no strict qw(refs);
($prefix, $pre, $pkg) = ($text =~ m/^((\$#|[\@\$%&])?(.*::)?)/);
@matches = grep /::$/, $pkg ? keys %$pkg : keys %::;
$pkg = '::' unless $pkg;
@matches = (@matches, grep (/^\w+$/ && ($sym = $pkg . $_, defined *$sym{$type{$pre}}), keys %$pkg));
}
my $entry;
for (; $i <= $#matches; $i++) {
$entry = $prefix . $matches[$i];
return $entry if ($entry =~ /^\Q$text/);
}
undef;
}</syntaxhighlight>
 
=={{header|Phix}}==
The phix interpreter has a readline interface, however the code involved is far too much to replicate here
(see p.exw, processCommandLine() which opens p.ini and populates default_commandlines, then invokes gets0()
from pgets0.ew with keyHandler() as a callback. Currently only tested/working on Windows, not linux.)
There are no "application specific commands", however you could init default_commandlines with some.
 
While the lack of code may disappoint, I think this is a closer match to the task intention than most.
 
A snapshot of running the interpreter: first I pressed ?, then F7, then "ed": keying "e" did little,
but "ed" auto-completed the "ix" part as that was then the only match.
<pre>
Phix hybrid interpreter/compiler.
 
Version 0.7.9 (32 bit Windows) Copyright Pete Lomax 2006..2016
 
Enter ? for options or filename to execute:?
 
<snip>
 
Press F7 to list prompt history, up/down to select.
 
Enter ? for options or filename to execute:
demo\pGUI\tee
demo\edix\edix
demo\win32demo\generic.exw
t61
p7
demo\win32demo\generic
-d! t01
-d! test/t01type.exw
edix
test\trace
p64
-c p64
-cp
-test
-c -test
-c e01
pgui
-d e01
pdemo
e01
use (pg) up/down to select:edix
</pre>
 
=={{header|Pike}}==
Line 49 ⟶ 908:
watch.pike is the solution from [[Simple database#Pike]]. this solution demonstrates how to retrofit an application with a readline interface by inheriting the original and overriding specific functions.
 
<langsyntaxhighlight lang="pike">#!/usr/bin/pike
 
inherit "watch.pike";
Line 114 ⟶ 973:
}
}
}</langsyntaxhighlight>
 
Sample session:
Line 138 ⟶ 997:
> save
> quit
 
=={{header|Python}}==
Python readline interface is enabled by default in the interpreter REPL, and can be enabled in user code simply by importing the readline module
<syntaxhighlight lang="python">#!/usr/bin/env python3
 
#
# A simple readline demo that does nothing.
# Interactive line editing and history active
#
 
import readline
 
while True:
try:
print(input('> '))
except:
break
</syntaxhighlight>
 
=={{header|Racket}}==
Racket's has a readline interface which is not used by default due to its license. This includes the usual readline-style editing, and tab-completion for Racket bindings. It is possible to use it as a library, or as a REPL convenience (both uses described [http://docs.racket-lang.org/readline/ in the documentation]) -- but it is better to use [http://docs.racket-lang.org/xrepl/ xrepl] which provides an enhanced command-line REPL and includes the readline interaction.
 
=={{header|Raku}}==
(formerly Perl 6)
 
Raku has a built in REPL that can be initiated by running the Raku executable without any parameters. It is fairly basic on its own but here are bindings available in the Raku ecosystem for [https://tiswww.case.edu/php/chet/readline/rltop.html GNU Readline] and/or [https://github.com/antirez/linenoise Linenoise] either of which will automatically provide command history, tab completion and more advance command line editing capability if installed. They are not included in the Raku distribution directly. There are incompatible licensing requirements and providing hooks for third party tools allows for more customization options.
 
Linenoise is generally the preferred option unless you really want the emacs compatible command line editing key bindings. Readline is arguably more powerful but is somewhat fiddly to set up.
 
If you are not inclined to install Readline ''or'' Linenoise, the REPL also works fairly well with 3rd party tools like rlwrap.
 
=={{header|REXX}}==
This REXX programs supports a '''REDO''' (re-do) with very limited editing to keep the program simple.
<br>It has a history (which can be interrogated) and asome fewof the simple (DOSMS) DOS commands.
<br>The HELP (or '''?'''), REDO, error checking, and abbreviations took up most of the program.
<br>"User" commands (subroutines) are identified with a leading period ('''.''') to make it easier to understand what's what.
<langsyntaxhighlight lang="rexx">/*REXX program to implementimplements a simple "readline" shell. (modeled after a DOS shell). */
trace off /*suppress echoing of non-zero RCretCodes*/
signal on syntax; signal on novaluenoValue /*handle REXX program errors. */
cmdscmdX='?|Help|MANualATTRIB CALendarCAL CHDIR COPY DEL DIR ECHO EDIT FC|FILECOMPAre FIND HISToryKEDIT LLL MEM MKDIR MORE REM KeditREXX',
'RMDIR SET TYPE VER XCOPY'LLL MEM MORE PROMPT Quit/* REMark◄──── Rexxthe REDOlegal/known Typecommands. VER' */
cls= 'CLS' /*define the program to clear screen. */
cmdX='CAL DIR ECHO FC FIND KEDIT LLL MEM MORE REM REXX TYPE VER'
cls@hist.= 'CLS'*** command not defined. ***' /*initialize the history database. /*define the pgm to clear screen.*/
@hist.#='***0 command not defined. ***' /*initializethe number of commands in the history database*/
prompt='Enter command ──or── ? ──or── Quit' /*the default PROMPT message text. */
hist#=0 /*number of commands in history. */
sw=linesize() /*some REXX don't have this BIF. */
prompt='Enter command ──or── ? ──or── Quit' /*default PROMPT msg.*/
sw=linesize()cls /*somestart REXXwith don'ta haveclean thisslate BIF(terminal). */
clsredoing=0 /*start with a clean slate./*flag for executing naked ReDO cmd. */
redoing=0 /*flag for[↓] executing nakeddo it ReDO'til the fat lady sings. */
do forever; if prompter() then iterate /*Nothing entered? Then go try again. */
select /* [↓] now then, let's rock n' roll. */
when wordpos(xxxF,cmdX)\==0 then call .cmdX
when xxxF=='EXIT' | xxxF="QUIT" then leave /*da fat lady is done singing*/
when xxxF=='HISTORY' then call .history
when xxxF=='HELP' then call .help
when xxxF=='PROMPT' then call .prompt
when xxxF=='REDO' then call .redo
otherwise call er 'unknown command:' xxx yyy
end /*select*/
end /*forever*/
 
say xxxF'ting···' /*say goodbye, 'cause it's polite to do*/
do forever
exit /*stick a fork in it, we're all done. */
call prompter; if xxx=='' then iterate
/*──────────────────────────────────────────────────────────────────────────────────────*/
select /*now then, let's rock & roll. */
er: say; say; say '****error****'; say; say arg(1); say; say; return
when wordpos(xxxF,cmdX)\==0 then call .cmdX
.prompt: if yyyU\=='' then prompt=yyy; return
when xxxF=='HISTORY' then call .history
.cmdX: xxxF yyy; return
when xxxF=='HELP' then call .help
/*──────────────────────────────────────────────────────────────────────────────────────*/
when xxxF=='PROMPT' then call .prompt
err: say; say; say center(' error! ', max(40, linesize()%2), "*"); say
when xxxF=='QUIT' then leave
do j=1 for arg(); say arg(j); say; end; say; exit 13
when xxxF=='REDO' then call .redo
/*──────────────────────────────────────────────────────────────────────────────────────*/
otherwise call er 'unknown command:' xxx yyy
noValue: syntax: call err 'REXX program' condition('C') "error",,
end /*select*/
condition('D'),'REXX source statement (line' sigl"):",sourceline(sigl)
end /*forever*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
.help: cmdsH= 'ATTRIB CHDIR CLS COPY DEL DIR ECHO EDIT FC FIND MEM MKDIR MORE PRINT',
'REM RMDIR SET TREE TYPE VER XCOPY' /*these have their own help via /? */
 
cmds= '?|Help|MANual ATTRIButes CALendar CD|CHDIR|CHANGEDir COPY DELete|ERASE',
say 'Quitting...' /*say goodbye, 'cause it's polite*/
'DELete|ERASE DIR ECHO EDIT FC|FILECOMPAre FIND HISTory Kedit LLL',
exit /*stick a fork in it, we're done.*/
'MEM MD|MKDIR|MAKEDir MORE PRINT PROMPT Quit|EXIT',
/*───────────────────────────────error handling subroutines and others.─*/
'R4 RD|RMDIR|REMOVEDir REGINA REMark Rexx REDO SET TREE Type VER'
er: say; say; say '****error!****'; say; say arg(1); say; say; return
err: say; say; say center(' error! ',max(40,linesize()%2),"*"); say
do j=1 for arg(); say arg(j); say; end; say; exit 13
 
say center(strip(xxx yyy),sw-1,'═'); cmds_=cmds; yyyF=unabbrev(yyy)
novalue: syntax: call err 'REXX program' condition('C') "error",,
 
condition('D'),'REXX source statement (line' sigl"):",,
help. = 'No help is available for the' yyy "command."
sourceline(sigl)
help.cal = 'shows a calendar for the current month or specified month.'
/*──────────────────────────────────.CMDX subroutine────────────────────*/
help.kedit = 'KEDITs the file specified.'
.cmdX: xxxF yyy; return
help.lll = 'shows a formatted listing of files in the current directory.'
/*──────────────────────────────────.HELP subroutine────────────────────*/
help.prompt= 'sets the PROMPT message to the specified text.'
.help: say center(strip(xxx yyy),sw-1,'═'); cmds_=cmds
help.quit = 'quits (exits) this program.'
cmdsH='CLS DIR ECHO FC FIND MEM MORE REM TYPE VER'
help. help.redo = 're-does Nothe helpcommand is# availablespecified for (or the' yyylast "command)."'
help.rexx = 'executes the REXX program specified.'
help.cal = 'shows a calendar for the current month or specified month.'
 
help.kedit = 'KEDITs the file specified.'
if yyy=='' then do j=1 while cmds_\==''
help.lll = 'shows a formatted listing of files in the current directory.'
parse var cmds_ x cmds_
help.prompt= 'sets the PROMPT message to the specified text.'
say left('',sw%2) changestr('|',x," | ")
help.q = 'exits this program.'
end /*j*/
help.redo = 're-does the a command # specified (or the last command).'
else select
help.rexx = 'executes the REXX program specified.'
when wordpos(yyyF,cmdsH)\==0 then yyyF '/?'
yyyF=unabbrev(yyy)
otherwise cmd?=yyyF
if yyy=='' then do j=1 while cmds_\==''
parse var cmds_ x cmds_ if left(help.yyyF,1)\==' ' then say yyyF ' ' help.yyyF
say left('',sw%2) changestr('|',x," | ") else say help.yyyF
end /*select*/
else selectreturn
/*──────────────────────────────────────────────────────────────────────────────────────*/
when wordpos(yyyF,cmdsH)\==0 then yyyF '/?'
.history: say center('history', sw-1, '═'); w=length(hist#)
otherwise cmd?=yyyF
if left(help.yyyF,1)\ do j=='1 for hist#; ' then say yyyFright(j,w) ' '═══►' help @hist.yyyFj; end /*j*/
return
else say help.yyyF
/*──────────────────────────────────────────────────────────────────────────────────────*/
end
prompter: if redoing then do; redoing=0; z=hist#-1 /*special case, bare REDO. */
return
parse var @hist.z xxx yyy
/*──────────────────────────────────.HISTORY subroutine─────────────────*/
end
.history: say center('history',sw-1,'═'); w=length(hist#)
else do; j if prompt\=1='' then do; say; say prompt; for hist#end
say right(j,w) '===>' @hist.j parse pull xxx yyy
end
 
return
xxxU=xxx; upper xxxU; if xxx=='' then return 1 /*No input? Then try again*/
/*──────────────────────────────────.PROMPT subroutine──────────────────*/
yyyU=yyy; upper yyyU; yyyU=strip(yyyU)
.prompt: if yyyU\=='' then prompt=yyy; return
hist#=hist#+1; /*bump the history counter.*/
/*──────────────────────────────────PROMPTER subroutine─────────────────*/
prompter: if redoing then do @hist.hist#=strip(xxx yyy) /*specialassign to casehistory. for naked REDO */
xxxF=unAbbrev(xxx) redoing=0; z=hist#-1 /*maybe expand abbreviation*/
return 0
parse var @hist.z xxx yyy
/*──────────────────────────────────────────────────────────────────────────────────────*/
end
.redo: select
else do
when yyyU=='' then if prompt\redoing==''1 then do; /*assume say;they want saythe prompt;last cmd. end*/
when words(yyy)\==1 then call er 'too many args specified parse pullfor' xxx yyy
when \datatype(yyy,'W') then call er "2nd arg isn't numeric for" endxxx
otherwise nop
xxxU=xxx; upper xxxU; if xxx=='' then return
end /*select*/
yyyU=yyy; upper yyyU; yyyU=strip(yyyU)
hist#=hist#+1; if redoing then return /*bumphandle thewith historykid countergloves. */
@hist.hist#=strip(xxx yyy)=yyy/1 /*assign to history. /*normalize it: +7 7. 1e1 007 7.0*/
say 'Re-doing:' @hist.yyy
xxxF=unAbbrev(xxx) /*expand the abbreviation (maybe)*/
@hist.yyy
return
return
/*──────────────────────────────────.redo subroutine────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
.redo:
select
when yyyU=='' then redoing=1 /*assume they want the last cmd. */
when words(yyy)\==1 then call er 'too many args specified for' xxx
when \datatype(yyy,'W') then call er "2nd arg isn't numeric for" xxx
otherwise nop
end
if redoing then return /*handle with kid gloves. */
yyy=yyy/1 /*normalize it: +7 7. 1e1 007 7.0*/
say 'Re-doing:' @hist.yyy
@hist.yyy
return
/*──────────────────────────────────UNABBREV subroutine─────────────────*/
unabbrev: procedure; arg ccc
select
when abbrev('CALENDAR',ccc,3) when abbrev('ATTRIBUTES' , ccc, 6) then return 'CALATTRIB'
when abbrev('CLEARSCREENCALENDAR',ccc,5) , ccc, 3) then return 'CLSCAL'
when abbrev('FILECOMPARE',ccc,9) then return when abbrev('FCCHANGEDIR' , ccc, 7) |,
when abbrev('HISTORY',ccc,4) then return ccc=='HISTORYCHDIR' |,
ccc=='CD' then return 'CHDIR'
when abbrev('HELP',ccc,1) |,
when abbrev('MANUALCLEARSCREEN', ccc,3 5) |, then return 'CLS'
ccc=='?' when abbrev('FILECOMPARE', ccc, 9) then return 'HELPFC'
when abbrev('KEDIT',ccc,1) then return when abbrev('KEDITDELETE' , ccc, 3) |,
when abbrev( ccc=='QUITERASE',ccc,1) then return 'QUITDEL'
when abbrev('REMARK',ccc,3) when abbrev('HISTORY' , ccc, 4) then return 'REMHISTORY'
when abbrev('REXX',ccc,1) then return when abbrev('REXXHELP' , ccc, 1) |,
when abbrev('TYPE',ccc,1) then return abbrev('TYPEMANUAL' , ccc, 3) |,
ccc=='?' then return 'HELP'
otherwise nop
when abbrev('MAKEDIR' , ccc, 5) |,
end
ccc=='MKDIR' |,
return ccc</lang>
ccc=='MD' then return 'MKDIR'
when abbrev('KEDIT' , ccc, 1) then return 'KEDIT'
when abbrev('QUIT' , ccc, 1) then return 'QUIT'
when abbrev('REMARK' , ccc, 3) then return 'REM'
when abbrev('REMOVEDIR' , ccc, 7) |,
ccc=='RMDIR' |,
ccc=='RD' then return 'RMDIR'
when abbrev('REXX' , ccc, 1) then return 'REXX'
when abbrev('TYPE' , ccc, 1) then return 'TYPE'
otherwise nop
end /*select*/
return ccc
</syntaxhighlight>
This REXX program makes use of &nbsp; '''LINESIZE''' &nbsp; REXX program (or BIF) which is used to determine the screen width (or linesize) of the terminal (console).
<br>The &nbsp; '''LINESIZE.REX''' &nbsp; REXX program is included here &nbsp; ──► &nbsp; [[LINESIZE.REX]].<br>
 
Some older REXXes don't have a '''changestr''' BIF, so one is included here &nbsp; ──► &nbsp; [[CHANGESTR.REX]].
<br><br>
'''output''' &nbsp; showing a sample session:
<pre style="height:120ex">
Enter command ──or── ? ──or── Quit
hel
═══════════════════════════════════════════hel══════════════════════════════════
? | Help | MANual
ATTRIButes
CALendar
CD | CHDIR | CHANGEDir
COPY
DELete | ERASE
DELete | ERASE
DIR
ECHO
EDIT
FC | FILECOMPAre
FIND
HISTory
Kedit
LLL
MEM
MD | MKDIR | MAKEDir
MORE
PRINT
PROMPT
Quit | EXIT
R4
RD | RMDIR | REMOVEDir
REGINA
REMark
Rexx
REDO
SET
TREE
Type
VER
 
Enter command ──or── ? ──or── Quit
rexx $mayan 123,456,787,654,321
╔════╗ ╔════╗ ╔════╗ ╔════╗ ╔════╗ ╔════╗ ╔════╗ ╔════╗ ╔════╗ ╔════╗ ╔════╗
║ ║ ║ ║ ║ ║ ║ ║ ║ ║ ║ ║ ║ ║ ║ ∙ ║ ║ ║ ║ ∙ ║ ║ ║
║ ∙∙ ║ ║ ║ ║ ║ ║ ║ ║ ∙∙ ║ ║ ║ ║ ║ ║────║ ║────║ ║────║ ║ ║
║────║ ║ ║ ║ ║ ║────║ ║────║ ║ ∙ ║ ║ ║ ║────║ ║────║ ║────║ ║ ║
║────║ ║ ∙ ║ ║ ∙∙ ║ ║────║ ║────║ ║────║ ║ ∙∙ ║ ║────║ ║────║ ║────║ ║ ∙ ║
╚════╝ ╚════╝ ╚════╝ ╚════╝ ╚════╝ ╚════╝ ╚════╝ ╚════╝ ╚════╝ ╚════╝ ╚════╝
 
Enter command ──or── ? ──or── Quit
cal
┌────────────────────────────────────────────────────────────────────────────┐
│ │
│ │
│ June 2012 │
│ │
│ │
│ Sunday Monday Tuesday Wednesday Thursday Friday Saturday │
├──────────┬──────────┬──────────┬──────────┬──────────┬──────────┬──────────┤
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
│ │ │ │ │ │ ─ 1 ─ │ 2 │
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
├──────────┼──────────┼──────────┼──────────┼──────────┼──────────┼──────────┤
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
│ 3 │ 4 │ 5 │ 6 │ 7 │ 8 │ 9 │
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
├──────────┼──────────┼──────────┼──────────┼──────────┼──────────┼──────────┤
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
│ 10 │ 11 │ 12 │ 13 │ 14 │ 15 │ 16 │
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
├──────────┼──────────┼──────────┼──────────┼──────────┼──────────┼──────────┤
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
│ 17 │ 18 │ 19 │ 20 │ 21 │ 22 │ 23 │
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
├──────────┼──────────┼──────────┼──────────┼──────────┼──────────┼──────────┤
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
│ 24 │ 25 │ 26 │ 27 │ 28 │ 29 │ 30 │
│ │ │ │ │ │ │ │
│ │ │ │ │ │ │ │
└──────────┴──────────┴──────────┴──────────┴──────────┴──────────┴──────────┘
 
 
Enter command ──or── ? ──or── Quit
LLL
mm/dd/yyyy hh:mm ──filesize── ─────────────────filename D:\*.*─────────────────
06/01/2012 10:36 2,322 DIV_GRID.TXT
05/13/2012 20:39 1,044 MOD_EXP.REX
05/13/2012 19:39 694 MOD_EXP.TXT
06/01/2012 02:32 1,439 RCOMBN.RX_
06/01/2012 02:24 7,181 READLINT.REX
05/29/2012 22:48 60 sub00.REX
──────────────────────12,740 <──────────────total bytes [6 files]
 
Enter command ──or── ? ──or── Quit
dir
Volume in drive D is -----D-----
Volume Serial Number is 68D0-6356
 
Directory of D:\
 
05/09/2012 12:40 <DIR> Config.Msi
12/16/2005 19:54 <DIR> Documents and Settings
01/15/2006 10:33 <DIR> Program Files
04/14/2010 19:58 <DIR> Recycled
12/16/2005 20:29 <DIR> System Volume Information
01/26/2011 00:21 <DIR> temp
12/16/2005 19:42 <DIR> WINDOWS
01/06/2006 14:43 211 boot.ini
06/01/2012 10:36 2,322 DIV_GRID.TXT
12/16/2005 20:18 0 IO.SYS
05/13/2012 20:39 1,044 MOD_EXP.REX
05/13/2012 19:39 694 MOD_EXP.TXT
12/16/2005 20:18 0 MSDOS.SYS
08/04/2004 12:00 47,564 NTDETECT.COM
08/04/2004 12:00 250,032 ntldr
06/01/2012 02:32 1,439 RCOMBN.RX_
06/01/2012 02:24 7,181 READLINT.REX
05/29/2012 22:48 60 sub00.REX
11 File(s) 310,547 bytes
7 Dir(s) 6,793,314,304 bytes free
 
Enter command ──or── ? ──or── Quit
help ver
════════════════════════════════════════help ver═════════════════════════════════════════
Displays the Windows XP version.
 
VER
 
Enter command ──or── ? ──or── Quit
ver
 
Microsoft Windows XP [Version 5.1.2600]
 
Enter command ──or── ? ──or── Quit
q
QUITting...
</pre>
 
{{omit from|GUISS}}
 
=={{header|Ruby}}==
This application provides auto-completion for these commands: ''search download open help history quit url prev past''.
<br>Auto-completion is applied by pressing the tab-key.
<br>A history of the commands is navigated by the up- and down-keys. All commands are just echoed, except "quit" which exits.
<br>It uses the Ruby 2.3 method Hash#to_proc.
<syntaxhighlight lang="ruby">require "readline"
require "abbrev"
 
commands = %w[search download open help history quit url prev past]
Readline.completion_proc = commands.abbrev.to_proc
 
while buf = Readline.readline(">", true) # true means: keep history.
exit if buf.strip == "quit"
p buf
end</syntaxhighlight>
 
=={{header|Sidef}}==
<syntaxhighlight lang="ruby">require('Term::ReadLine')
 
var term = %O<Term::ReadLine>.new('Example')
 
term.addhistory('foo')
term.addhistory('bar')
 
loop {
var cmd = term.readline("Prompt: ") \\ break
 
if (cmd ~~ %w[q quit]) {
break
}
 
say "You inserted <<#{cmd}>>"
}</syntaxhighlight>
 
=={{header|Wren}}==
{{trans|Go}}
<syntaxhighlight lang="wren">import "io" for Stdin, Stdout
 
class ReadLine {
static start {
__hist = []
System.print("Enter a command, type help for a listing.")
while (true) {
System.write(">")
Stdout.flush()
var cmd = Stdin.readLine().trim()
if (cmd == "exit") {
return
} else if (cmd == "hello") {
hello_
} else if (cmd == "hist") {
hist_
} else if (cmd == "help") {
help_
} else {
System.print("Unknown command, try again")
}
}
}
 
static hello_ {
System.print("Hello World!")
__hist.add("hello")
}
 
static hist_ {
if (__hist.count == 0) {
System.print("No history")
} else {
for (cmd in __hist) System.print(" - %(cmd)")
}
__hist.add("hist")
}
 
static help_ {
System.print("Available commands:")
System.print(" hello")
System.print(" hist")
System.print(" exit")
System.print(" help")
__hist.add("help")
}
}
 
ReadLine.start</syntaxhighlight>
 
{{out}}
Sample session (as Go):
<pre>
Enter a command, type help for a listing.
>hit
Unknown command, try again
>hist
No history
>help
Available commands:
hello
hist
exit
help
>hello
Hello World!
>hist
- hist
- help
- hello
>exit
</pre>
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