Modulinos: Difference between revisions
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{{draft task|Basic language learning}}
It is useful to be able to execute a main() function only when a program is run directly. This is a central feature in programming scripts
Examples from
Sometimes getting the [[ScriptName]] is required in order to determine when to run main().
Care when manipulating command line arguments, due to subtle exec security constraints that may or not be enforced on implicit argv[0]. https://ryiron.wordpress.com/2013/12/16/argv-silliness/
: ''This is still a draft task, and the current task description has caused mega confusion. See '''[[Talk:Modulinos]]''' for numerous attempts to understand the task and to rewrite the task description.''
: '''The task [[Executable library]] is written to replace this task.''' ''This task's future is in doubt as its aims are not clear enough.''
<br><br>
=={{header|11l}}==
<syntaxhighlight lang="11l">// life.11l
F meaning_of_life()
R ‘*’.code
:start:
print(‘Main: The meaning of life is ’meaning_of_life())</syntaxhighlight>
<syntaxhighlight lang="11l">// death.11l
print(‘Life means ’life:meaning_of_life()‘.’)
print(‘Death means nothing.’)</syntaxhighlight>
=={{header|AppleScript}}==
AppleScript's equivalent of a main() function is a <tt>run</tt> handler, which can be either implicit or explicit:
<syntaxhighlight lang="applescript">display dialog "Hello"</syntaxhighlight>
or
<syntaxhighlight lang="applescript">on run
display dialog "Hello"
end run</syntaxhighlight>
A <tt>run</tt> handler's only executed when the script containing it is explicity ''run'', either from another script or application or as an application in its own right. It's not executed when a script's simply loaded as a library, although it can subsequently be so in the unlikely event of this being desirable. Scripts saved as applications aren't recognised by the "Libraries" system introduced in Mac OS X 10.9, but can be loaded and/or run using the older <tt>load script</tt> and <tt>run script</tt> commands. Script code can tell if it's running in its own application or being executed by an external agent by comparing its file path with that of the agent:
<syntaxhighlight lang="applescript">on run
if ((path to me) = (path to current application)) then
display dialog "I'm running in my own application."
else
display dialog "I'm being run from another script or application."
end if
end run</syntaxhighlight>
=={{header|Arturo}}==
===Library===
<syntaxhighlight lang="rebol">; modulinos - library
meaningOfLife: function [][
42
]
if standalone? ->
print ~"Library: The meaning of life is |meaningOfLife|"</syntaxhighlight>
{{out}}
<pre>Library: The meaning of life is 42</pre>
===Main===
<syntaxhighlight lang="rebol">do.import relative "modulinos - library.art"
print ~"Life means |meaningOfLife|."
print "Death means invisible scary skeletons."</syntaxhighlight>
{{out}}
<pre>Life means 42.
Death means invisible scary skeletons.</pre>
=={{header|C}}==
{{works with|GCC}}
C programs cannot normally do scripted main, because main() is implicitly included by another program, test.c, even though scriptedmain.h omits any main() prototype. However, preprocessor instructions can hide main unless a compiler flag is explicitly set.
Example
<syntaxhighlight lang="sh">$ make
./scriptedmain
Main: The meaning of life is 42
./test
Test: The meaning of life is</syntaxhighlight>
Makefile
<syntaxhighlight lang="make">all: scriptedmain test
./scriptedmain
./test
scriptedmain: scriptedmain.c scriptedmain.h
gcc -o scriptedmain -DSCRIPTEDMAIN scriptedmain.c scriptedmain.h
test: test.c scriptedmain.h scriptedmain.c
gcc -o test test.c scriptedmain.c scriptedmain.h
clean:
-rm scriptedmain
-rm test
-rm scriptedmain.exe
-rm test.exe</syntaxhighlight>
scriptedmain.h
<syntaxhighlight lang
scriptedmain.c
<
int meaning_of_life() {
Line 32 ⟶ 120:
}
#ifdef SCRIPTEDMAIN
int main() {
printf("Main: The meaning of life is %d\n", meaning_of_life());
return 0;
}
#endif</syntaxhighlight>
test.c
<
#include <stdio.h>
Line 48 ⟶ 140:
printf("Test: The meaning of life is %d\n", meaning_of_life());
return 0;
}</
=={{header|C++}}==
C++ programs cannot normally do scripted main, because main() is implicitly included by another program, test.c, even though scriptedmain.h omits any main() prototype.
Example
<syntaxhighlight lang="sh">$ make
./scriptedmain
Main: The meaning of life is 42
./test
Test: The meaning of life is 42</syntaxhighlight>
Makefile
<syntaxhighlight lang="make">all: scriptedmain test
./scriptedmain
./test
scriptedmain: scriptedmain.cpp scriptedmain.h
g++ -o scriptedmain -static-libgcc -static-libstdc++ -DSCRIPTEDMAIN scriptedmain.cpp scriptedmain.h
test: test.cpp scriptedmain.h scriptedmain.cpp
g++ -o test -static-libgcc -static-libstdc++ test.cpp scriptedmain.cpp scriptedmain.h
clean:
-rm scriptedmain
-rm test
-rm scriptedmain.exe
-rm test.exe</syntaxhighlight>
scriptedmain.h
<syntaxhighlight lang
scriptedmain.cpp
<
using namespace std;
Line 67 ⟶ 185:
}
#ifdef SCRIPTEDMAIN
int main() {
cout << "Main: The meaning of life is " << meaning_of_life() << endl;
return 0;
}
#endif</syntaxhighlight>
test.cpp
<
#include <iostream>
Line 82 ⟶ 203:
extern int meaning_of_life();
int main(
cout << "Test: The meaning of life is " << meaning_of_life() << endl;
return 0;
}</
=={{header|
Uses [https://github.com/kumarshantanu/lein-exec lein-exec].
scriptedmain.
<syntaxhighlight lang="clojure">":";exec lein exec $0 ${1+"$@"}
":";exit
(ns scriptedmain
(:gen-class))
(defn meaning-of-life [] 42)
(defn -main [& args]
(println "Main: The meaning of life is" (meaning-of-life)))
(when (.contains (first *command-line-args*) *source-path*)
(apply -main (rest *command-line-args*)))</syntaxhighlight>
test.clj:
<syntaxhighlight lang="clojure">":";exec lein exec $0 ${1+"$@"}
":";exit
(ns test
(:gen-class))
(load-string (slurp "scriptedmain.clj"))
(defn -main [& args]
(println "Test: The meaning of life is" (scriptedmain/meaning-of-life)))
(when (.contains (first *command-line-args*) *source-path*)
(apply -main (rest *command-line-args*)))</syntaxhighlight>
=={{header|CoffeeScript}}==
scriptedmain.coffee:
<syntaxhighlight lang="coffeescript">#!/usr/bin/env coffee
meaningOfLife = () -> 42
exports.meaningOfLife = meaningOfLife
main = () ->
console.log "Main: The meaning of life is " + meaningOfLife()
if not module.parent then main()</syntaxhighlight>
test.coffee:
<syntaxhighlight lang="coffeescript">#!/usr/bin/env coffee
sm = require "./scriptedmain"
console.log "Test: The meaning of life is " + sm.meaningOfLife()</syntaxhighlight>
=={{header|Common Lisp}}==
Line 186 ⟶ 268:
~/.clisprc.lisp
<
(set-dispatch-macro-character #\# #\!
(lambda (stream character n)
(declare (ignore character n))
(read-line stream nil nil t)
nil))</
scriptedmain.lisp
<
#|
exec clisp -q -q $0 $0 ${1+"$@"}
Line 225 ⟶ 307:
args
:test #'(lambda (x y) (search x y :test #'equalp)))
(main args)))</
test.lisp
<
#|
exec clisp -q -q $0 $0 ${1+"$@"}
Line 236 ⟶ 318:
(load "scriptedmain.lisp")
(format t "Test: The meaning of life is ~a~%" (meaning-of-life))</
=={{header|D}}==
D manages to implement scriptedmain through the use of version directives, which require special options to rdmd and dmd.
scriptedmain.d:
<syntaxhighlight lang="d">#!/usr/bin/env rdmd -version=scriptedmain
module scriptedmain;
import std.stdio;
int meaningOfLife() {
return 42;
}
version (scriptedmain) {
void main(string[] args) {
writeln("Main: The meaning of life is ", meaningOfLife());
}
}</syntaxhighlight>
test.d:
<syntaxhighlight lang="d">#!/usr/bin/env rdmd -version=test
import scriptedmain;
import std.stdio;
version (test) {
void main(string[] args) {
writeln("Test: The meaning of life is ", meaningOfLife());
}
}</syntaxhighlight>
Example:
<syntaxhighlight lang="sh">$ ./scriptedmain.d
Main: The meaning of life is 42
$ ./test.d
Test: The meaning of life is 42
$ dmd scriptedmain.d -version=scriptedmain
$ ./scriptedmain
Main: The meaning of life is 42
$ dmd test.d scriptedmain.d -version=test
$ ./test
Test: The meaning of life is 42</syntaxhighlight>
=={{header|Dart}}==
scriptedmain.dart:
<syntaxhighlight lang="dart">#!/usr/bin/env dart
#library("scriptedmain");
meaningOfLife() {
return 42;
}
main() {
print("Main: The meaning of life is ${meaningOfLife()}");
}</syntaxhighlight>
test.dart:
<syntaxhighlight lang="dart">#!/usr/bin/env dart
#import("scriptedmain.dart", prefix: "scriptedmain");
main() {
print("Test: The meaning of life is ${scriptedmain.meaningOfLife()}");
}</syntaxhighlight>
Example:
<syntaxhighlight lang="sh">$ ./scriptedmain.dart
Main: The meaning of life is 42
$ ./test.dart
Test: The meaning of life is 42</syntaxhighlight>
=={{header|Emacs Lisp}}==
Line 243 ⟶ 402:
scriptedmain.el
<
;;; Shebang from John Swaby
Line 251 ⟶ 410:
(defun main ()
(message "Main: The meaning of life is %d" (meaning-of-life)))</
test.el
<
;;; Shebang from John Swaby
Line 263 ⟶ 422:
(setq load-path (cons default-directory load-path))
(load "scriptedmain.el" nil t)
(message "Test: The meaning of life is %d" (meaning-of-life)))</
=={{header|EMal}}==
{{trans|Wren}}
<syntaxhighlight lang="emal">
^|We have created a module named ModulinosPart.emal.
|^
in Org:RosettaCode
type ModulinosPart
fun meaningOfLife = int by block do return 42 end
fun main = void by block do writeLine("The meaning of life is " + meaningOfLife() + ".") end
if Runtime.direct() do main() end
</syntaxhighlight>
{{out}}
<pre>
emal.exe Org\RosettaCode\ModulinosPart.emal
The meaning of life is 42.
</pre>
<syntaxhighlight lang="emal">
^|Then we create a new module named Modulinos.emal,
|this imports the previous module.
|^
in Org:RosettaCode
load :ModulinosPart
type Modulinos
fun main = int by List args
writeLine("Who says the meaning of life is " + ModulinosPart.meaningOfLife() + "?")
return 0
end
exit main(Runtime.args)
</syntaxhighlight>
{{out}}
<pre>
emal.exe Org\RosettaCode\Modulinos.emal
Who says the meaning of life is 42?
</pre>
=={{header|Erlang}}==
Erlang has scripted main by default. scriptedmain.erl must be compiled before test.erl can access its functions.
Makefile:
<syntaxhighlight lang="make">all: t
erl -noshell -s scriptedmain
erl -noshell -s test
scriptedmain.beam: scriptedmain.erl
erlc scriptedmain.erl
test.beam: test.erl
erlc test.erl
clean:
-rm *.beam</syntaxhighlight>
<syntaxhighlight lang="erlang">-module(scriptedmain).
-export([meaning_of_life/0, start/0]).
meaning_of_life() -> 42.
start() ->
io:format("Main: The meaning of life is ~w~n", [meaning_of_life()]),
init:stop().</syntaxhighlight>
test.erl:
<syntaxhighlight lang="erlang">-module(test).
-export([start/0]).
-import(scriptedmain, [meaning_of_life/0]).
init:stop().</syntaxhighlight>
=={{header|F Sharp|F#}}==
Note 1: F# supports the scriptedmain behavior, but F# does not support hybrid script-compiled code files. The following programs work provided that they are compiled and then run, as .fs files, not interpreted or dotslashed as .fsx files.
Note 2: fsharpc has a backwards file ordering: Specify any dependencies BEFORE the code that depends on them.
Note 3: fsharpc also has that unpredictable DOS-flavored command line flag syntax, so the --out requires a colon between it and its value, and -h only generates an error; use --help instead.
Note 4: In Unix, mono is required to run F# executables. In Windows, mono is not required for execution.
Example:
<syntaxhighlight lang="sh">$ make
fsharpc --out:scriptedmain.exe ScriptedMain.fs
fsharpc --out:test.exe ScriptedMain.fs Test.fs
$ mono scriptedmain.exe
Main: The meaning of life is 42
$ mono test.exe
Test: The meaning of life is 42</syntaxhighlight>
Makefile:
<syntaxhighlight lang="make">all: scriptedmain.exe test.exe
scriptedmain.exe: ScriptedMain.fs
fsharpc --nologo --out:scriptedmain.exe ScriptedMain.fs
test.exe: Test.fs ScriptedMain.fs
fsharpc --nologo --out:test.exe ScriptedMain.fs Test.fs
clean:
-rm *.exe</syntaxhighlight>
ScriptedMain.fs:
<syntaxhighlight lang="fsharp">namespace ScriptedMain
module ScriptedMain =
let meaningOfLife = 42
let main =
printfn "Main: The meaning of life is %d" meaningOfLife</syntaxhighlight>
Test.fs:
<syntaxhighlight lang="fsharp">module Test =
open ScriptedMain
let main =
printfn "Test: The meaning of life is %d" ScriptedMain.meaningOfLife</syntaxhighlight>
=={{header|Factor}}==
Line 294 ⟶ 553:
Example:
<
Main: The meaning of life is 42
$ ./test.factor
Test: The meaning of life is 42</
~/.factor-rc:
<
USING: kernel vocabs.loader parser sequences lexer vocabs.parser ;
Line 308 ⟶ 567:
: include-vocab ( vocab -- ) dup ".factor" append parse-file append use-vocab ;
SYNTAX: INCLUDING: ";" [ include-vocab ] each-token ;</
scriptedmain.factor:
<
USING: io math.parser ;
Line 321 ⟶ 580:
: main ( -- ) meaning-of-life "Main: The meaning of life is " write number>string print ;
MAIN: main</
test.factor:
<
INCLUDING: scriptedmain ;
Line 333 ⟶ 592:
: main ( -- ) meaning-of-life "Test: The meaning of life is " write number>string print ;
MAIN: main</
=={{header|Forth}}==
Line 339 ⟶ 598:
Given this awful running reference:
<
: go ( -- )
." The meaning of life is " Douglas-Adams . cr ;</
The bulk of Forth systems provide a way to generate an executable that enters GO (ar any word) on start.
Line 348 ⟶ 607:
{{works with|SwiftForth|SwiftForth|4.0}}
<
program douglas-adams</
Which creates a file named 'douglas-adams' that you can then run. If this is all in the same file, you can load the file, test parts of it, and then exit (or shell out) to run the executable.
Line 357 ⟶ 616:
{{works with|gforth}}
<
42 constant Douglas-Adams
.( The meaning of life is ) Douglas-Adams . cr bye</
Adding #! as a comment, as gforth does, is trivial. For a means by which this script could distinguish between 'scripted execution' and otherwise, a symlink like 'forthscript' could easily be used, and the zeroth OS argument tested for, but there's no convention.
Line 366 ⟶ 625:
{{works with|gforth}}
<
42 constant Douglas-Adams
Line 374 ⟶ 633:
[THEN]
cr .( Why aren't you running this as a script? It only provides a constant.)</
=={{header|FreeBASIC}}==
{{trans|Ring}}
<syntaxhighlight lang="freebasic">
Function meaningoflife() As Byte
Dim As Byte y = 42
Return y
End Function
Sub main()
Print "Main: The meaning of life is "; meaningoflife()
End Sub
main()
Sleep
</syntaxhighlight>
{{out}}
<pre>
Main: The meaning of life is 42
</pre>
=={{header|Go}}==
Go doesn't support scripted main directly.
Although the [https://github.com/mcandre/modulinos examples] linked to above include an example for Go, this is only a work around, not an emulation. To emulate a modulino, we need to proceed as in the [[https://rosettacode.org/wiki/Executable_library#Go Executable library]] task and split the 'main' package into two.
First create these two files in the 'modulino' directory:
<syntaxhighlight lang="go">// modulino.go
package main
import "fmt"
func MeaningOfLife() int {
return 42
}
func libMain() {
fmt.Println("The meaning of life is", MeaningOfLife())
}</syntaxhighlight>
<syntaxhighlight lang="go">// modulino_main.go
package main
func main() {
libMain()
}</syntaxhighlight>
To emulate a modulino:
{{out}}
<pre>
$ go run modulino
The meaning of life is 42
</pre>
Now create this file in the 'mol' directory:
<syntaxhighlight lang="go">// mol.go
package main
import "fmt"
func main() {
fmt.Println("The meaning of life is still", MeaningOfLife())
}</syntaxhighlight>
and copy modulino.go to the 'mol' directory. The library can then be used in the 'normal' way:
{{out}}
<pre>
$ go run mol
The meaning of life is still 42
</pre>
=={{header|Groovy}}==
Example:
<syntaxhighlight lang="sh">$ ./ScriptedMain.groovy
Main: The meaning of life is 42
$ ./Test.groovy
Test: The meaning of life is 42</syntaxhighlight>
ScriptedMain.groovy:
<syntaxhighlight lang="groovy">#!/usr/bin/env groovy
class ScriptedMain {
static def meaningOfLife = 42
static main(args) {
println "Main: The meaning of life is " + meaningOfLife
}
}</syntaxhighlight>
Test.groovy:
<syntaxhighlight lang="groovy">#!/usr/bin/env groovy
println "Test: The meaning of life is " + ScriptedMain.meaningOfLife</syntaxhighlight>
=={{header|Haskell}}==
Haskell has scripted main, but getting scripted main to work with compiled scripts is tricky.
<
Main: The meaning of life is 42
$ runhaskell test.hs
Line 388 ⟶ 747:
$ ghc -fforce-recomp -o test -main-is Test test.hs scriptedmain.hs
$ ./test
Test: The meaning of life is 42</
scriptedmain.hs
<
-- Compile:
Line 404 ⟶ 763:
main :: IO ()
main = putStrLn $ "Main: The meaning of life is " ++ show meaningOfLife</
test.hs
<
-- Compile:
Line 419 ⟶ 778:
main :: IO ()
main = putStrLn $ "Test: The meaning of life is " ++ show meaningOfLife</
=={{header|Io}}==
ScriptedMain.io:
<syntaxhighlight lang="io">#!/usr/bin/env io
ScriptedMain := Object clone
ScriptedMain meaningOfLife := 42
if( isLaunchScript,
"Main: The meaning of life is #{ScriptedMain meaningOfLife}" interpolate println
)</syntaxhighlight>
test.io:
<syntaxhighlight lang="io">#!/usr/bin/env io
"Test: The meaning of life is #{ScriptedMain meaningOfLife}" interpolate println</syntaxhighlight>
<syntaxhighlight lang="sh">$ ./ScriptedMain.io
Main: The meaning of life is 42
$ ./test.io
Test: The meaning of life is 42</syntaxhighlight>
=={{header|J}}==
modulinos.ijs:
<syntaxhighlight lang="j">#!/usr/bin/env ijconsole
meaningOfLife =: 42
main =: monad define
echo 'Main: The meaning of life is ',": meaningOfLife
exit ''
)
shouldrun =: monad define
if. 1 e. 'modulinos.ijs' E. ;ARGV do.
main 0
end.
)
shouldrun 0</syntaxhighlight>
test.j:
<syntaxhighlight lang="j">#!/usr/bin/env jconsole
load 'modulinos.ijs'
echo 'Test: The meaning of life is ',": meaningOfLife
exit ''</syntaxhighlight>
Example:
<syntaxhighlight lang="sh">$ ./modulinos.ijs
Main: The meaning of life is 42
$ ./test.j
Test: The meaning of life is 42</syntaxhighlight>
=={{header|Java}}==
Line 463 ⟶ 847:
ScriptedMain.java
<
public static int meaningOfLife() {
return 42;
Line 471 ⟶ 855:
System.out.println("Main: The meaning of life is " + meaningOfLife());
}
}</
Test.java
<
public static void main(String[] args) {
System.out.println("Test: The meaning of life is " + ScriptedMain.meaningOfLife());
}
}</
=={{header|JavaScript}}==
{{Works with|Node.js}}
Node.js has scripted main.
scriptedmain.js
<syntaxhighlight lang="javascript">#!/usr/bin/env node
function meaningOfLife() { return 42; }
exports.meaningOfLife = meaningOfLife;
function main() {
console.log("Main: The meaning of life is " + meaningOfLife());
}
if (!module.parent) { main(); }</syntaxhighlight>
test.js
<syntaxhighlight lang="javascript">#!/usr/bin/env node
var sm = require("./scriptedmain");
console.log("Test: The meaning of life is " + sm.meaningOfLife());</syntaxhighlight>
=={{header|Julia}}==
Julia does not use scripted main by default, but can be set to run as such. Modules generally use a /test unit test subdirectory instead.
<br />
In module file Divisors.jl:
<syntaxhighlight lang="julia">module Divisors
using Primes
export properdivisors
function properdivisors(n::T) where T <: Integer
0 < n || throw(ArgumentError("number to be factored must be ≥ 0, got $n"))
1 < n || return T[]
!isprime(n) || return T[one(T), n]
f = factor(n)
d = T[one(T)]
for (k, v) in f
c = T[k^i for i in 0:v]
d = d*c'
d = reshape(d, length(d))
end
sort!(d)
return d[1:end-1]
end
function interactiveDivisors()
println("\nFind proper divisors between two numbers.\nFirst number: ")
lo = (x = tryparse(Int64, readline())) == nothing ? 0 : x
println("\nSecond number: ")
hi = (x = tryparse(Int64, readline())) == nothing ? 10 : x
lo, hi = lo > hi ? (hi, lo) : (lo, hi)
println("Listing the proper divisors for $lo through $hi.")
for i in lo:hi
println(lpad(i, 7), " => ", rpad(properdivisors(i), 10))
end
end
end
# some testing code
if occursin(r"divisors.jl"i, Base.PROGRAM_FILE)
println("This module is running as main.\n")
Divisors.interactiveDivisors()
end
</syntaxhighlight>
In a user file getdivisors.jl:
<syntaxhighlight lang="julia">include("divisors.jl")
using .Divisors
n = 708245926330
println("The proper divisors of $n are ", properdivisors(n))
</syntaxhighlight>
=={{header|LLVM}}==
LLVM can have scripted main a la C, using the weak attribute.
<
llvm-as scriptedmain.ll
llc scriptedmain.bc
Line 494 ⟶ 957:
gcc -o test test.s scriptedmain.s
./test
Test: The meaning of life is 42</
Makefile
<
EXECUTABLE_TEST=test
Line 519 ⟶ 982:
-rm test.bc
-rm scriptedmain.s
-rm scriptedmain.bc</
scriptedmain.ll
<
declare i32 @printf(i8* noalias nocapture, ...)
Line 537 ⟶ 1,000:
ret i32 0
}</
test.ll
<
declare i32 @printf(i8* noalias nocapture, ...)
Line 553 ⟶ 1,016:
ret i32 0
}</
=={{header|Lua}}==
Line 560 ⟶ 1,023:
scriptedmain.lua
<
function meaningoflife()
Line 574 ⟶ 1,037:
else
module(..., package.seeall)
end</
test.lua
<
sm = require("scriptedmain")
print("Test: The meaning of life is " .. sm.meaningoflife())</
=={{header|Make}}==
Example
<syntaxhighlight lang="sh">$ make -f scriptedmain.mf
The meaning of life is 42
(Main)
$ make -f test.mf
The meaning of life is 42
(Test)</syntaxhighlight>
scriptedmain.mf
<syntaxhighlight lang="make">all: scriptedmain
meaning-of-life:
@echo "The meaning of life is 42"
scriptedmain: meaning-of-life
@echo "(Main)"
</syntaxhighlight>
test.mf
<syntaxhighlight lang="make">all: test
test:
@make -f scriptedmain.mf meaning-of-life
@echo "(Test)"
</syntaxhighlight>
=={{header|Mathematica}}/{{header|Wolfram Language}}==
scriptedmain.ma
<syntaxhighlight lang="mathematica">#!/usr/bin/env MathKernel -script
MeaningOfLife[] = 42
ScriptName[] = Piecewise[
{
{"Interpreted", Position[$CommandLine, "-script", 1] == {}}
},
$CommandLine[[Position[$CommandLine, "-script", 1][[1,1]] + 1]]
]
Program = ScriptName[];
If[StringMatchQ[Program, ".*scriptedmain.*"],
Print["Main: The meaning of life is " <> ToString[MeaningOfLife[]]]
]</syntaxhighlight>
test.ma:
<syntaxhighlight lang="mathematica">#!/usr/bin/env MathKernel -script
Get["scriptedmain.ma"]
Print["Test: The meaning of life is " <> ToString[MeaningOfLife[]]]</syntaxhighlight>
Example:
<syntaxhighlight lang="sh">$ ./scriptedmain.ma
Main: The meaning of life is 42
$ ./test.ma
Test: The meaning of life is 42</syntaxhighlight>
In Mac and Windows, the output will be surrounded by spurious quotes.
=={{header|Mozart/Oz}}==
Makefile:
<syntaxhighlight lang="make">all: run
run: scriptedmain test
./scriptedmain
./test
scriptedmain: scriptedmain.oz
ozc -x scriptedmain.oz
scriptedmain.ozf: scriptedmain.oz
ozc -c scriptedmain.oz
test: scriptedmain.ozf test.oz
ozc -x test.oz
clean:
-rm test
-rm scriptedmain
-rm *.ozf
-rm *.exe
</syntaxhighlight>
scriptedmain.oz:
<syntaxhighlight lang="oz">functor
export
meaningOfLife: MeaningOfLife
import
System
Application
Property
Regex at 'x-oz://contrib/regex'
define
fun {MeaningOfLife} 42 end
local ScriptName = {Property.get 'application.url'} in
if {Regex.search "scriptedmain" ScriptName} \= false then
{System.printInfo "Main: The meaning of life is "#{Int.toString {MeaningOfLife}}#"\n"}
{Application.exit 0}
end
end
end
</syntaxhighlight>
test.oz:
<syntaxhighlight lang="oz">functor
import
ScriptedMain
System
Application
Property
Regex at 'x-oz://contrib/regex'
define
local ScriptName = {Property.get 'application.url'} in
if {Regex.search "test" ScriptName} \= false then
{System.printInfo "Test: The meaning of life is "#{Int.toString {ScriptedMain.meaningOfLife}}#"\n"}
{Application.exit 0}
end
end
end</syntaxhighlight>
=={{header|newLISP}}==
Line 587 ⟶ 1,175:
scriptedmain.lsp
<
(context 'SM)
Line 599 ⟶ 1,187:
(if (find "scriptedmain" (main-args 1)) (main))
(context MAIN)</
test.lsp
<
(load "scriptedmain.lsp")
(println (format "Test: The meaning of life is %d" (SM:meaning-of-life)))
(exit)</
=={{header|
Nim provides the predicate <code>isMainModule</code> to use with conditional compilation. Here is an example:
<syntaxhighlight lang="Nim">proc p*() =
## Some exported procedure.
echo "Executing procedure"
# Some code to execute to initialize the module.
echo "Initializing the module"
when isMainModule:
# Some code to execute if the module is run directly, for instance code to test the module.
echo "Running tests"
</syntaxhighlight>
{{out}}
When run directly, the result of execution is:
<pre>Initializing the module
Running tests
</pre>
If we call “p” from another module, we get:
<pre>Initializing the module
Executing procedure
</pre>
=={{header|Objective-C}}==
scriptedmain.h:
<syntaxhighlight lang="objc">#import <objc/Object.h>
@interface ScriptedMain: Object {}
+ (int)meaningOfLife;
@end</syntaxhighlight>
scriptedmain.m:
<syntaxhighlight lang="objc">#import "scriptedmain.
#import <Foundation/Foundation.h>
@implementation ScriptedMain
+ (int)meaningOfLife {
return 42;
}
@end
int __attribute__((weak)) main(int argc, char **argv) {
@autoreleasepool {
printf("Main: The meaning of life is %d\n", [ScriptedMain meaningOfLife]);
}
return 0;
}</syntaxhighlight>
test.m:
<syntaxhighlight lang="objc">#import "scriptedmain.h"
#import <Foundation/Foundation.h>
int main(int argc, char **argv) {
@autoreleasepool {
printf("Test: The meaning of life is %d\n", [ScriptedMain meaningOfLife]);
}
return 0;
}</syntaxhighlight>
<syntaxhighlight lang="sh">$ gcc -o scriptedmain -lobjc -framework foundation scriptedmain.m
$ gcc -o test -lobjc -framework foundation test.m scriptedmain.m
$ ./scriptedmain
Main: The meaning of life is 42
$ ./test
Test: The meaning of life is 42</syntaxhighlight>
=={{header|OCaml}}==
scriptedmain.ml
<syntaxhighlight lang="ocaml">let meaning_of_life = 42
let main () =
Printf.printf "Main: The meaning of life is %d\n"
meaning_of_life
let () =
if not !Sys.interactive then
main ()</syntaxhighlight>
Invoked as a script:
<syntaxhighlight lang="sh">$ ocaml scriptedmain.ml
Main: The meaning of life is 42</syntaxhighlight>
Loaded into an ocaml toplevel/utop:
<syntaxhighlight lang="text">$ ocaml
...
# #use "scriptedmain.ml";;
val meaning_of_life : int = 42
val main : unit -> unit = <fun>
# meaning_of_life;;
- : int = 42
# </syntaxhighlight>
The limit of this technique is "avoiding running something when loading a script interactively". It's not applicable to other uses, like adding an example script to a file normally used as a library, as that code will also fire when users of the library are run.
=={{header|Octave}}/{{header|MATLAB}}==
Line 689 ⟶ 1,316:
meaningoflife.m
<
function y = meaningoflife()
Line 699 ⟶ 1,326:
endfunction
main();</
test.m
<
printf("Test: The meaning of life is %d", meaningoflife());</
=={{header|Pascal}}==
{{works with|Free_Pascal}}
Makefile:
<syntaxhighlight lang="make">all: scriptedmain
scriptedmain: scriptedmain.pas
fpc -dscriptedmain scriptedmain.pas
test: test.pas scriptedmain
fpc test.pas
clean:
-rm test
-rm scriptedmain
-rm *.o
-rm *.ppu</syntaxhighlight>
scriptedmain.pas:
<syntaxhighlight lang="pascal">{$IFDEF scriptedmain}
program ScriptedMain;
{$ELSE}
unit ScriptedMain;
interface
function MeaningOfLife () : integer;
implementation
{$ENDIF}
function MeaningOfLife () : integer;
begin
MeaningOfLife := 42
end;
{$IFDEF scriptedmain}
begin
write('Main: The meaning of life is: ');
writeln(MeaningOfLife())
{$ENDIF}
end.</syntaxhighlight>
test.pas:
<syntaxhighlight lang="pascal">program Test;
uses
ScriptedMain;
begin
write('Test: The meaning of life is: ');
writeln(MeaningOfLife())
end.</syntaxhighlight>
Example:
<syntaxhighlight lang="sh">$ make
$ ./scriptedmain
Main: The meaning of life is: 42
$ make test
$ ./test
Test: The meaning of life is: 42</syntaxhighlight>
=={{header|Perl}}==
Perl has scripted main. The code inside <tt>unless(caller) { ... }</tt> only runs when <tt>Life.pm</tt> is the main program.
<
# Life.pm
Line 724 ⟶ 1,409:
unless(caller) {
print "Main: The meaning of life is " . meaning_of_life() . "\n";
}</
<
# death.pl
Line 735 ⟶ 1,420:
print "Life means " . Life::meaning_of_life . ".\n";
print "Death means invisible scary skeletons.\n";</
=={{header|Phix}}==
There is a builtin for this, which can even be asked to skip an arbitrary number of stack frames and that way find out exactly where it was effectively called from.
<!--<syntaxhighlight lang="phix">(notonline)-->
<span style="color: #008080;">without</span> <span style="color: #008080;">js</span> <span style="color: #000080;font-style:italic;">-- (includefile)</span>
<span style="color: #004080;">string</span> <span style="color: #000000;">mori</span> <span style="color: #0000FF;">=</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">include_file</span><span style="color: #0000FF;">()=</span><span style="color: #000000;">1</span><span style="color: #0000FF;">?</span><span style="color: #008000;">"main"</span><span style="color: #0000FF;">:</span><span style="color: #008000;">"an include"</span><span style="color: #0000FF;">)</span>
<!--</syntaxhighlight>-->
=={{header|PHP}}==
Line 755 ⟶ 1,434:
scriptedmain.php
<
function meaning_of_life() {
return 42;
Line 767 ⟶ 1,446:
main($argv);
}
?></
test.php
<
require_once("scriptedmain.php");
echo "Test: The meaning of life is " . meaning_of_life() . "\n";
?></
=={{header|PicoLisp}}==
PicoLisp normally does it the other way round: It calls main from the command line with the '-' syntax if desired. Create an executable file (chmod +x) "life.l":
<
(de meaningOfLife ()
Line 785 ⟶ 1,464:
(de lifemain ()
(prinl "Main: The meaning of life is " (meaningOfLife))
(bye) )</
and an executable file (chmod +x) "test.l":
<
(load "life.l")
(prinl "Test: The meaning of life is " (meaningOfLife))
(bye)</
Test:
<pre>$ ./life.l -lifemain
Line 803 ⟶ 1,482:
Python has scripted main.
<
# life.py
Line 811 ⟶ 1,490:
if __name__ == "__main__":
print
<
# death.py
Line 819 ⟶ 1,498:
from life import meaning_of_life
print
print
=={{header|R}}==
A way to check if code is running at "top level" is to check <code>length(sys.frames())</code>. This value will be zero for a file being run with <code>Rscript</code>, the <code>--file=</code> argument, or at the command line, and will be greater than 0 in all other conditions (such as package loading or code being sourced from another file.)
<syntaxhighlight lang="r">#!/usr/bin/env Rscript
meaningOfLife <- function() {
42
}
main <- function(args) {
cat("Main: The meaning of life is", meaningOfLife(), "\n")
}
if (length(sys.frames()) > 0) {
args <- commandArgs(trailingOnly = FALSE)
main(args)
q("no")
}</syntaxhighlight>
test.R
<syntaxhighlight lang="r">#!/usr/bin/env Rscript
source("scriptedmain.R")
cat("Test: The meaning of life is", meaningOfLife(), "\n")
q("no")</syntaxhighlight>
=={{header|Racket}}==
scriptedmain.rkt:
<syntaxhighlight lang="racket">#!/usr/bin/env racket
#lang racket
(provide meaning-of-life)
(define (meaning-of-life) 42)
(module+ main (printf "Main: The meaning of life is ~a\n" (meaning-of-life)))</syntaxhighlight>
test.rkt:
<syntaxhighlight lang="racket">#!/usr/bin/env racket
#lang racket
(module+ main
(require "scriptedmain.rkt")
(printf "Test: The meaning of life is ~a\n" (meaning-of-life)))</syntaxhighlight>
=={{header|Raku}}==
(formerly Perl 6)
Raku automatically calls MAIN on direct invocation, but this may be a multi dispatch, so a library may have multiple "scripted mains".
<syntaxhighlight lang="raku" line>class LUE {
has $.answer = 42;
}
multi MAIN ('test') {
say "ok" if LUE.new.answer == 42;
}
multi MAIN ('methods') {
say ~LUE.^methods;
}</syntaxhighlight>
=={{header|REXX}}==
<syntaxhighlight lang="rexx">/*REXX program detects whether or not it is a "scripted main" program. */
parse source . howInvoked @fn /*query REXX how this pgm got invoked. */
say 'This program ('@fn") was invoked as a: " howInvoked
if howInvoked\=='COMMAND' then do
say 'This program ('@fn") wasn't invoked via a command."
exit 12
end
/*╔════════════════════════════════════════════════════════════════════════════════╗
║ At this point, we know that this program was invoked via the "command line" ║
║ or a program using the "command interface" and not via another program. ║
╚════════════════════════════════════════════════════════════════════════════════╝*/
/*────────────────────────────── The main code follows here ... ────────────────────────*/
say
say '(from' @fn"): and away we go ···"</syntaxhighlight> <br><br>
=={{header|Ring}}==
<syntaxhighlight lang="ring">
# Project : Modulinos
func meaningoflife()
y = 42
return y
func main()
see "Main: The meaning of life is " + meaningoflife() + nl
</syntaxhighlight>
Output:
<pre>
Main: The meaning of life is 42
</pre>
=={{header|Ruby}}==
Ruby has scripted main.
<syntaxhighlight lang="ruby"># life.rb
def meaning_of_life
42
end
if __FILE__ == $0
puts "Main: The meaning of life is #{meaning_of_life}"
end</syntaxhighlight>
<syntaxhighlight lang="ruby"># death.rb
require 'life'
puts "Life means #{meaning_of_life}."
puts "Death means invisible scary skeletons."</syntaxhighlight>
=={{header|Rust}}==
'''Note:''' this code is deprecated, and does not compile with Rust 1.0.0 and newer.
Makefile:
<syntaxhighlight lang="make">all: scriptedmain
scriptedmain: scriptedmain.rs
rustc scriptedmain.rs
test: test.rs scriptedmain.rs
rustc --lib scriptedmain.rs
rustc test.rs -L .
clean:
-rm test
-rm -rf *.dylib
-rm scriptedmain
-rm -rf *.dSYM</syntaxhighlight>
scriptedmain.rs:
<syntaxhighlight lang="rust">#[link(name = "scriptedmain")];
use std;
fn meaning_of_life() -> int {
ret 42;
}
fn main() {
std::io::println("Main: The meaning of life is " + core::int::to_str(meaning_of_life(), 10u));
}</syntaxhighlight>
test.rs:
<syntaxhighlight lang="rust">use scriptedmain;
use std;
fn main() {
std::io::println("Test: The meaning of life is " + core::int::to_str(scriptedmain::meaning_of_life(), 10u));
}</syntaxhighlight>
Example:
<syntaxhighlight lang="sh">$ make
$ make test
$ ./scriptedmain
Main: The meaning of life is 42
$ ./test
Test: The meaning of life is 42</syntaxhighlight>
=={{header|SAC}}==
Makefile:
<syntaxhighlight lang="make">all: scriptedmain
scriptedmain: ScriptedMain.sac
sac2c -o scriptedmain ScriptedMain.sac -Dscriptedmain
test: test.sac ScriptedMain.sac
sac2c ScriptedMain.sac
sac2c -o test test.sac
clean:
-rm test
-rm test.c
-rm libScriptedMainTree.so
-rm libScriptedMainMod.so
-rm libScriptedMainMod.a
-rm scriptedmain
-rm scriptedmain.c</syntaxhighlight>
ScriptedMain.sac:
<syntaxhighlight lang="c">#ifndef scriptedmain
module ScriptedMain;
#endif
use StdIO: all;
use Array: all;
export all;
int meaning_of_life() {
return(42);
}
#ifdef scriptedmain
int main() {
printf("Main: The meaning of life is %d\n", meaning_of_life());
return(0);
}
#endif</syntaxhighlight>
test.sac:
<syntaxhighlight lang="c">use StdIO: all;
use Array: all;
use ScriptedMain: all;
int main() {
printf("Test: The meaning of life is %d\n", meaning_of_life());
return(0);
}</syntaxhighlight>
Example:
<syntaxhighlight lang="sh">$ make
$ make test
$ ./scriptedmain
Main: The meaning of life is 42
$ ./test
Test: The meaning of life is 42</syntaxhighlight>
=={{header|Scala}}==
{{libheader|Scala}}
{{works with|Scala|2.10.2}}
===Unix shell script===
This code must be stored as a shell script.
<syntaxhighlight lang="bash">#!/bin/sh
exec scala "$0" "$@"
!#
def hailstone(n: Int): Stream[Int] =
n #:: (if (n == 1) Stream.empty else hailstone(if (n % 2 == 0) n / 2 else n * 3 + 1))
val nr = argv.headOption.map(_.toInt).getOrElse(27)
val collatz = hailstone(nr)
println(s"Use the routine to show that the hailstone sequence for the number: $nr.")
println(collatz.toList)
println(s"It has ${collatz.length} elements.")</syntaxhighlight>
===Windows Command Script===
This code must be stored as a Windows Command Script e.g. Hailstone.cmd
<syntaxhighlight lang="winbatch">::#!
@echo off
call scala %0 %*
pause
goto :eof
::!#
def hailstone(n: Int): Stream[Int] =
n #:: (if (n == 1) Stream.empty else hailstone(if (n % 2 == 0) n / 2 else n * 3 + 1))
val nr = argv.headOption.map(_.toInt).getOrElse(27)
val collatz = hailstone(nr)
println(s"Use the routine to show that the hailstone sequence for the number: $nr.")
println(collatz.toList)
println(s"It has ${collatz.length} elements.")
</syntaxhighlight>
{{out}}
<pre>C:\>Hailstone.cmd 42
Use the routine to show that the hailstone sequence for the number: 42.
List(42, 21, 64, 32, 16, 8, 4, 2, 1)
It has 9 elements.</pre>
=={{header|Scheme}}==
{{Works with|Chicken Scheme}}
Chicken Scheme has the {{{ -ss }}} flag for the interpreter, but compiled Chicken Scheme programs do not have scripted main unless the behavior is added manually to the code.
scriptedmain.scm
<syntaxhighlight lang="scheme">#!/bin/sh
#|
exec csi -ss $0 ${1+"$@"}
exit
|#
(use posix)
(require-extension srfi-1) ; lists
(define (meaning-of-life) 42)
(define (main args)
(display (format "Main: The meaning of life is ~a\n" (meaning-of-life)))
(exit))
(define (program)
(if (string=? (car (argv)) "csi")
(let ((s-index (list-index (lambda (x) (string-contains x "-s")) (argv))))
(if (number? s-index)
(cons 'interpreted (list-ref (argv) (+ 1 s-index)))
(cons 'unknown "")))
(cons 'compiled (car (argv)))))
(if (equal? (car (program)) 'compiled)
(main (cdr (argv))))</syntaxhighlight>
test.scm
<syntaxhighlight lang="scheme">#!/bin/sh
#|
exec csi -ss $0 ${1+"$@"}
exit
|#
(define (main args)
(load "scriptedmain.scm")
(display (format "Test: The meaning of life is ~a\n" (meaning-of-life)))
(exit))</syntaxhighlight>
=={{header|Sidef}}==
<syntaxhighlight lang="ruby"># Life.sm
func meaning_of_life {
42
}
if (__FILE__ == __MAIN__) {
say "Main: The meaning of life is #{meaning_of_life()}"
}</syntaxhighlight>
<syntaxhighlight lang="ruby"># test.sf
include Life
say "Test: The meaning of life is #{Life::meaning_of_life()}."</syntaxhighlight>
=={{header|Smalltalk}}==
Line 828 ⟶ 1,834:
Example
<
$ ./scriptedmain.st
Line 834 ⟶ 1,840:
$ ./test.st
Test: The meaning of life is 42</
package.xml
<
<package>
<name>ScriptedMain</name>
Line 844 ⟶ 1,850:
<file>scriptedmain.st</file>
</package>
</packages></
scriptedmain.st
<
"exit"
Line 863 ⟶ 1,869:
(((Smalltalk getArgc) > 0) and: [ ((Smalltalk getArgv: 1) endsWith: 'scriptedmain.st') ]) ifTrue: [
main value.
].</
test.st
<
"exit"
Line 873 ⟶ 1,879:
PackageLoader fileInPackage: 'ScriptedMain'.
Transcript show: 'Test: The meaning of life is ', ((ScriptedMain meaningOfLife) printString); cr.</
=={{header|
Swift requires a number of hacks and boilerplate, but it is possible to write a modulino nevertheless.
Example
<syntaxhighlight lang="shell">$ make
mkdir -p bin/
swiftc -D SCRIPTEDMAIN -o bin/ScriptedMain ScriptedMain.swift
swiftc -emit-library -module-name ScriptedMain -emit-module ScriptedMain.swift
mkdir -p bin/
swiftc -D TEST -o bin/Test Test.swift -I "." -L "." -lScriptedMain -module-link-name ScriptedMain
bin/ScriptedMain
Main: The meaning of life is 42
bin/Test
Test: The meaning of life is 42</syntaxhighlight>
Makefile
<syntaxhighlight lang="make">all: bin/ScriptedMain bin/Test
bin/ScriptedMain
bin/Test
bin/ScriptedMain: ScriptedMain.swift
mkdir -p bin/
swiftc -D SCRIPTEDMAIN -o bin/ScriptedMain ScriptedMain.swift
ScriptedMain.swiftmodule: ScriptedMain.swift
swiftc -emit-library -module-name ScriptedMain -emit-module ScriptedMain.swift
bin/Test: Test.swift ScriptedMain.swiftmodule
mkdir -p bin/
swiftc -D TEST -o bin/Test Test.swift -I "." -L "." -lScriptedMain -module-link-name ScriptedMain
clean:
-rm -rf bin/
-rm *.swiftmodule
-rm *.swiftdoc
-rm *.dylib
</syntaxhighlight>
ScriptedMain.swift
<syntaxhighlight lang="swift">import Foundation
public class ScriptedMain {
public var meaningOfLife = 42
public init() {}
public class func main() {
var meaning = ScriptedMain().meaningOfLife
println("Main: The meaning of life is \(meaning)")
}
#if SCRIPTEDMAIN
@objc class ScriptedMainAutoload {
@objc class func load() {
ScriptedMain.main()
}
}
#endif
</syntaxhighlight>
Test.swift
<syntaxhighlight lang="swift">import Foundation
import ScriptedMain
public class Test {
public class func main() {
var meaning = ScriptedMain().meaningOfLife
println("Test: The meaning of life is \(meaning)")
}
}
#if TEST
@objc class TestAutoload {
@objc class func load() {
Test.main()
}
}
#endif
</syntaxhighlight>
=={{header|Tcl}}==
<
puts "Directory: [pwd]"
puts "Program: $::argv0"
Line 942 ⟶ 1,979:
if {$::argv0 eq [info script]} {
main {*}$::argv
}</
=={{header|UNIX Shell}}==
Line 949 ⟶ 1,986:
scriptedmain.sh
<
meaning_of_life() {
Line 963 ⟶ 2,000:
then
main
fi</
test.sh
<syntaxhighlight lang
path=$(dirname -- "$0")
source "$path/scriptedmain"
meaning_of_life
echo "Test: The meaning of life is $?"
</syntaxhighlight>
=={{header|Wren}}==
As far as Wren is concerned, a modulino and an executable library seem to be different names for the same thing. This therefore uses the same technique as the [[Executable_library#Wren]] task to create a simple modulino.
Note that Wren doesn't need or normally use a ''main()'' function to start a script, though we use one here to make the example clearer.
First we create a module for our modulino:
<syntaxhighlight lang="wren">/* Modulinos.wren */
var MeaningOfLife = Fn.new { 42 }
var main = Fn.new {
System.print("The meaning of life is %(MeaningOfLife.call()).")
}
// Check if it's being used as a library or not.
import "os" for Process
if (Process.allArguments[1] == "Modulinos.wren") { // if true, not a library
main.call()
}</syntaxhighlight>
and run it to make sure it works OK when run directly:
{{output}}
<pre>
The meaning of life is 42.
</pre>
Next we create another module which imports the modulino:
<syntaxhighlight lang="wren">/* Modulinos_main.wren */
import "./Modulinos" for MeaningOfLife
var main = Fn.new {
System.print("Who says the meaning of life is %(MeaningOfLife.call())?")
}
main.call()</syntaxhighlight>
and run this to make sure the modulino's ''main()'' function doesn't run:
{{output}}
<pre>
Who says the meaning of life is 42?
</pre>
=={{header|ZX Spectrum Basic}}==
Line 976 ⟶ 2,060:
On the ZX Spectrum, there is no main function as such, however a saved program can be made to start running from a particular line number by providing the line number as a parameter to save command. If the program is being merged as a module, then it does not run automatically. The following example will save the program in memory so that it starts running from line 500:
<
{{omit from|Ada}}
|