Write program in your favorite language in another language [closed]

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The determined Real Programmer can write Fortran programs in any language.

from Real Programmers Don't Use Pascal

Your task is to write program in your programming language of choice, but you are allowed to use only another language. That is, throw away all coding conventions from one language and replace them with coding conventions from other language. The more the better. Make your program look as if it was written in another language.

For example, Python fan who hates Java could write following Python program in Java:

void my_function() {
 int i = 9 ;
 while(i>0) {
 System.out.println("Hello!") ;
 i = i - 1 ;}}

Pascal enthusiast forced to use C could write this:

#define begin {
#define end }
#define then
#define writeln(str) puts(str)
if (i == 10) then
begin
 writeln("I hate C");
end

You have to write complete program. The program desn't have to do anything useful.

Good Luck. This is a popularity contest so the code with the most votes wins!

• Ismael Miguel: @m.buettner create your file with the extension .litcoffee. It might help.
• luser droog: A little long (and previously-written; and not self-contained) for an answer, but: Postscript scanner in Postscript in C.
• Peter Taylor: I don't think you (or the majority of the answers) understand the point of the quote. It's not that a Real Programmer writes code that looks lexically like Fortran even though he's writing in Pascal or LISP: it's that he applies a Fortran way of thinking even when writing in Pascal or LISP; e.g. "As all Real Programmers know, the only useful data structure is the Array.". Great answers would be procedural code in Prolog, functional code in C, object-oriented code in Pascal.
• itsjeyd: I hope someone's gonna do a Lisp dialect in, well, anything but another Lisp dialect...
• Joshua Taylor: @itsjeyd Greenspun's Tenth Rule Of Programming: "Any sufficiently complicated C or Fortran program contains an ad-hoc, informally-specified, bug-ridden, slow implementation of half of CommonLisp."

Answer 1

C in C++

#include <stdio.h>
int main(int argc, char** argv)
{
 printf("Hello world!\n");
 return 0;
}

• el.pescado - нет войне: I see what you did there;)
• Agi Hammerthief: Well, that's a cheap trick, seeing as C++ is 'backwards compatible' with C.
• Martin Ender: @AlexM. I think it would be more in the spirit of the question if this was a longer (procedural) example which would clearly benefit from using some classes and which uses other C idioms where some STL goodness would be much more reasonable (say char* instead of std::string).
• nneonneo: Valid in C, C++, Objective-C, and Objective-C++! What a wonderfully polyglot answer.
• Thomas: @BenJackson Psh, real C programmers use char *argv[]!

Answer 2

x86 assembly in GNU C

No, I didn't just use the asm keyword, since the question established this is for real programmers... this should run fine on ARM.

(Just to prove the point, I didn't "write" the assembly at all - it's the output produced by (削除) GCC (削除ここまで) Clang (503.0.38) for the commented code at the top, blindly translated into macros.)

This only works in 32-bit mode. That's fine since real programmers code to the word size anyway.

#include <stdio.h>
#include <stdint.h>
/*
int fac(int x) {
 if (x < 1) return 1; else return x * fac(x - 1);
}
int fib(int x) {
 if (x < 2) return x; else return fib(x - 1) + fib(x - 2);
}
int main(void) {
 int a = fib(10), b = fac(10);
 printf("%d %d\n", a, b);
 return 0;
}
*/
typedef union REG {
 intptr_t i; int _i; void * v; union REG * r;
} REG;
#define LPAREN (
#define RPAREN )
#define MACRO(N) ); N##_MACRO LPAREN
#define push MACRO(PUSH)
#define pop MACRO(POP)
#define mov MACRO(MOV)
#define sub MACRO(SUB)
#define add MACRO(ADD)
#define imul MACRO(IMUL)
#define cmp MACRO(CMP)
#define jge MACRO(JGE)
#define jmp MACRO(JMP)
#define call MACRO(CALL)
#define ret MACRO(RET) _
#define label MACRO(LABEL)
#define NO_OP(X) 
#define PUSH_MACRO(VAL) *(esp -= 4) = (REG)(VAL)
#define POP_MACRO(DST) (DST) = (typeof(DST))(esp->i); esp += 4
#define MOV_MACRO(VAL, DST) (DST) = (typeof(DST))((REG)VAL).i;
#define SUB_MACRO(VAL, DST) CMP_MACRO(VAL, DST); \
 (DST) = (typeof(DST))(((REG)DST).i - ((REG)VAL).i)
#define ADD_MACRO(VAL, DST) DST = (typeof(DST))(((REG)DST).i + ((REG)VAL).i); \
 ZF = ((REG)DST).i == 0; OF = 0; SF = ((REG)DST).i < 0
#define IMUL_MACRO(VAL, DST) DST = (typeof(DST))(((REG)DST).i * ((REG)VAL).i); \
 ZF = ((REG)DST).i == 0; OF = 0; SF = ((REG)DST).i < 0
#define CMP_MACRO(L, R) CMP_MACRO_(((REG)L).i, ((REG)R).i)
#define CMP_MACRO_(L, R) (OF = 0, ZF = L == R, SF = (R - L) < 0)
#define JGE_MACRO(TGT) if (SF == OF) { goto TGT; } else {}
#define JMP_MACRO(TGT) goto TGT;
#define CALL_MACRO(PROC) CALL_MACRO_(PROC, __COUNTER__)
#define CALL_MACRO_(PROC, CTR) PUSH_MACRO(CTR - STARTIP); \
 goto PROC; case CTR - STARTIP:
#define RET_MACRO(_) eip = esp->i; esp += 4; if (eip) { continue; } else { goto *finalreturn; }
#define LABEL_MACRO(NAME) NAME
#define MY_ASM(X) do { const int STARTIP = __COUNTER__; \
 switch(eip) { case 0: MY_ASM_1 X } } while (1);
#define MY_ASM_1(X) MY_ASM_2(NO_OP LPAREN 0 X RPAREN;)
#define MY_ASM_2(X) X
#define CAT(L, R) _CAT(L, R)
#define _CAT(L, R) L##R
#define callASM(F) callASM_(F, CAT(_TMP_, __COUNTER__))
#define callASM_(F, LABEL) (({ PUSH_MACRO(0); stackbase = esp; finalreturn = &&LABEL; \
 goto F; LABEL:; }), (intptr_t)eax)
const int STACKSIZE = 4096;
REG callstack[STACKSIZE], * stackbase;
REG * eax, * ecx, * edx, * ebx, * esi, * edi, * esp, * ebp;
int SF, ZF, OF, eip; void * finalreturn;
int main(void) {
 eax = ecx = edx = ebx = esi = edi = esp = ebp = &callstack[STACKSIZE - 1];
 eip = 0;
 finalreturn = &&TOP; TOP:
 PUSH_MACRO(10);
 int a = callASM(_fac);
 PUSH_MACRO(10);
 int b = callASM(_fib);
 printf("%d %d\n", a, b);
 return 0;
 MY_ASM((
 label _fac: // @fac
 push ebp
 mov esp, ebp
 sub 24, esp
 mov 8[ebp], eax
 mov eax, (-8)[ebp]
 cmp 1, (-8)[ebp]
 jge LBB0_2
 mov 1, (-4)[ebp]
 jmp LBB0_3
 label LBB0_2:
 mov (-8)[ebp], eax
 mov (-8)[ebp], ecx
 sub 1, ecx
 mov ecx, *esp
 mov eax, (-12)[ebp] // 4-byte Spill
 call _fac
 mov (-12)[ebp], ecx // 4-byte Reload
 imul eax, ecx
 mov ecx, (-4)[ebp]
 label LBB0_3:
 mov (-4)[ebp], eax
 add 24, esp
 pop ebp
 ret
 label _fib: // @fib
 push ebp
 mov esp, ebp
 sub 24, esp
 mov 8[ebp], eax
 mov eax, (-8)[ebp]
 cmp 2, (-8)[ebp]
 jge LBB1_2
 mov (-8)[ebp], eax
 mov eax, (-4)[ebp]
 jmp LBB1_3
 label LBB1_2:
 mov (-8)[ebp], eax
 sub 1, eax
 mov eax, *esp
 call _fib
 mov (-8)[ebp], ecx
 sub 2, ecx
 mov ecx, *esp
 mov eax, (-12)[ebp] // 4-byte Spill
 call _fib
 mov (-12)[ebp], ecx // 4-byte Reload
 add eax, ecx
 mov ecx, (-4)[ebp]
 label LBB1_3:
 mov (-4)[ebp], eax
 add 24, esp
 pop ebp
 ret
 ))
}

Just look at all those casts. Casts mean I'm a realer programmer than the compiler, right?

• Ilmari Karonen: +1, that's... twisted. ;) I really like how you handled call, in particular.
• anon: Wow. That's a great piece of work.
• Ben Jackson: I had an assembler for the C64 that worked sort of like this. It added BASIC keywords for all the 6510 instructions and I remember you wrapped for pass=1:3...next around it. Executing it in the BASIC interpreter assembled it.
• Nicu Stiurca: This is pure poetry.
• teh internets is made of catz: This is tough man, the compiler sure is amazed.

Answer 3

JavaScript in C

I like JavaScript, and I like C. Surely mixing the two would create the best language in the world!!11elevenone

#include <stdio.h>
#define function int
#define var int
struct { int (*log)(const char *,...); } console = { printf };
/* From here on only JavaScript! */
function fac(x){
 if(x < 2) return 1;
 return x * fac(x - 1);
}
function main(){
 console.log("Hello world!\n");
 for(var i = 0; i < 10; i++){
 console.log("%i! = %i\n", i, fac(i));
 }
 return 0;
}
// *Should* we export the main function of this library??/
exports.main = main;

Nope, that's revolting. Ah well... Using a format-string for console.log isn't very JavaScript-y, but it does work (at least in Chrome's developer console).

• Martin Ender: +1 ... Except if this was proper JavaScript you would have to call that main somehow ;)
• Kninnug: @m.buettner True, added a dirty hack to pretend we're exporting the main function, like one would do in Node.js libraries.
• Martin Ender: Well, the actual trick is the trigraph. You might as well just do main(); in that last line, so you don't need any Node.js assumption. ;) Anyway, I'd +1 again if I could.

Answer 4

English in C

#include <stdio.h>
#define This
#define program int main() {
#define aims
#define to
#define output printf(
#define some
#define example
#define text(a) #a
#define the
#define screen "\n");
#define it 
#define also
#define will
#define calculate ;int a = 
#define result
#define of
#define and
#define print ; printf("%d\n", a);
#define seriously return 0; }
This program aims to output some example text (Hello) to the screen;
it also will calculate the result of 3 + 4 and print the result; seriously

Any ideas to eliminate the ;?

• Kyle Strand: Seriously, you guys.
• Joshua Taylor: why define the twice?
• urzeit: better safe than sorry ;-)
• Nicu Stiurca: Now make it a haiku.
• mbomb007: Can you #define . ;

Answer 5

Brainfuck in JavaScript

Javascript is a difficult language ! Let us use Brainfuck, a more understandable language :o)

eval(
//write your easy code below
"++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>."
//end of easy code
.replace(/\]/g,'}')
.replace(/\[/g,'while(a[i]){')
.replace(/\+/g,'a[i]++;')
.replace(/-/g,'a[i]--;')
.replace(/>/g,'i++;')
.replace(/</g,'i--;')
.replace(/\./g,'o+=String.fromCharCode(a[i]);')
.replace(/,/g,'a[i]=u.charCodeAt(j++);')
.replace(/^/,'var a=new Array(1000).join(\'0\').split(\'\'),i=500,o=\'\',u=prompt(\'Enter input if needed\'),j=0;')
.replace(/$/,'alert(o)')
)

I guess I wrote a brainfuck interpreter in javascript.

The example above simply ouputs Hello World! and ignore the input (no , symbol).
But that works with inputs too ! For example, try ,+>,+>,+>,+<<<.>.>.>. and type golf in the dialog. It will ouputs the next characters in ASCII table : hpmg

EDIT : Short explanation for people who don't know brainfuck.
Imagine an infinite array of integers a initialized to zero everywhere, a pointer on one element of this array i, and a user input u.
Brainfuck is really easy to learn but difficult to write :

• + increments to current value : a[i]++
• - decrements it : a[i]--
• > makes to pointer points the next element : i++
• < the previous : i--
• [ and ] define a loop which breaks when current value is zero : while (a[i]) { ... }
• . print the current element : String.fromCharCode(a[i])
• , sets the current element with user input : u.charCodeAt(...)

• Agi Hammerthief: +1 for the humour in stating that brainfuck is more understandable than JavaScript.
• ashastral: Are you sure that the Brainfuck characters inside of the replace statements don't affect the program?
• undergroundmonorail: @fra This file isn't a brainfuck program, it's a javascript program that contains a brainfuck program that's converted to javascript at runtime.
• Michael M.: Well, --i faster than i-- ? Seems false since years : jsperf.com/decrementgolf.
• SebastianH: This not only is very creative submission to the contest, but also explains brainfuck syntax very clearly. +10 if I could!

Answer 6

I think the brilliant Lennart Augustsson has already won this twice.

First, here's an example of his "weekend hack" implementation of BASIC as a Haskell Monadic DSL, from 2009:

import BASIC
main = runBASIC' $ do
 10 LET I =: 1
 20 LET S =: 0
 30 LET S =: S + 1/I
 40 LET I =: I + 1
 50 IF I <> 100000000 THEN 30
 60 PRINT "Almost infinity is"
 70 PRINT S
 80 END

It works by overloading the number type. The line numbers are really functions that accept arguments. The rest of the line is arguments to the function. The function returns a representation of the Abstract Syntax Tree for the BASIC interpreter to go to work on.

I also recommend you check out Augustsson's entry to the 2006 International Obfuscated C Contest, in which he managed to squeeze into 4k:

• A bytecode interpreter, written in a subset of C (which he calls Obfuscated C).
• An Obfuscated C -> bytecode compiler, written in bytecode.

They can share the same file because the bytecode is placed inside C comments.

It's a few years since I followed Augustsson's work, so there may well be other brilliant things he's come up with since then....

• Hans Lundmark: It's Augustsson, not Augustssen.

Answer 7

PHP and Javascript

This is a polyglot:

You can run this code in both languages:

if("0円"=='0円')
{
 function printf(){
 $b=Array();
 $a=$b['slice']['call'](arguments);
 $a=$a['join']('');
 console.log($a);
 return $a.length;
 };
 function strtoupper($s){return $s['toUpperCase']();}
 function count($a){return $a['length'];}
}
printf('this is cool!');
$c=Array('a','b','c','d');
for($i=0,$l=count($c);$i<$l;++$i)printf("\n",strtoupper($c[$i]));

The trick here is that Javascript uses escape sequences in strings starting with ' and ".
On the other hand, PHP only uses escape sequences in strings starting with " and <<<.

Then, we declare the function printf, which is similar to print but outputs a formated string in PHP.

PHP requires that vars start with $, while Javascript simply allows.

• Blackhole: Nobody's using Array(...) in JS, and it's clearly array(...) in PHP. [...] would be far better ;) !
• Ismael Miguel: I don't care if people use Array() in JS or not: I care that I have a TRUE polyglot. I'm making one of the worst JS crimes with this code but all I want is that it runs and does the exact same thing in both, but looking like JS and PHP at the same time.
• Ismael Miguel: And btw, [...] is invalid in PHP <5.4.0, which is bad....... If I throw this into PHP 4, 5 or Javascript, I expect it to work, instead of giving syntax errors everywhere.
• Blackhole: If you want your code to look like JS, you must use [...], which seems pretty standard in PHP, and therefore is OK for your goal. And by the way, PHP < 5.4? Time to update, guy...
• Ismael Miguel: Compatibility is more important than "looks". And Array is the RIGHT name of the Array object's constructor. Basicly, using [] is the same as Array(). I don't see anything bad with it. But I have one simple question: Works? (btw, I have to use php 5.3.28 at work.)

Answer 8

Brainfuck in JS

[][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[
!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[
+!+[]]]]][([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(
![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!
![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+
[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]
]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[
]+!+[]+!+[]+!+[]]]]+([][[]]+[])[+[[+!+[]]]]+(![]+[])[+[[!+[]+!+[]+!+[]]]]+(!!
[]+[])[+[[+[]]]]+(!![]+[])[+[[+!+[]]]]+([][[]]+[])[+[[+[]]]]+([][(![]+[])[+[[
+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!
![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+
[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[
[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!!
[]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+[])[+[[!+[]+!+[]+!+[]+!+[]
+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]((![]+[])[+[[+!+[]]]]+(![]+[])[+[[!+[]+!+
[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]+(!![]+[])[+[[+[]]]
]+([][(![]+[])[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[
+[[!+[]+!+[]]]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[
+[[+!+[]]]]]+[])[+[[+!+[]]]+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+[+!+[]]+([][(![]+[]
)[+[[+[]]]]+([][[]]+[])[+[[!+[]+!+[]+!+[]+!+[]+!+[]]]]+(![]+[])[+[[!+[]+!+[]]
]]+(!![]+[])[+[[+[]]]]+(!![]+[])[+[[!+[]+!+[]+!+[]]]]+(!![]+[])[+[[+!+[]]]]]+
[])[+[[+!+[]]]+[[!+[]+!+[]+!+[]+!+[]+!+[]+!+[]]]])()

• Michael M.: I don't see any brainfuck here. Not even a single char in ><,.-
• null: @Michael: Who said it isn't a program that makes an infinite loop?
• user16402: is this JSF*ck?
• nandhp: How on Earth does it do that?
• Matti Virkkunen: Oo. Somebody finally did this. I spent some time trying to figure out how to write a JS program using only the characters +![]() but never could quite figure it out. I need to analyze this when I have time...

Answer 9

This is one of the 2005 IOCCC winners, a C program that, except by that bunch of defines, looks like a java program:

/*
 * Sun's Java is often touted as being "portable", even though my code won't
 * suddenly become uber-portable if it's in Java. Truth is, Java's one of
 * the most ugly, slow, and straitjacketed languages ever. It's popular
 * mainly because people hear the word "portable" and go "ewww".
 *
 * This program, then, is dedicated to bringing about the death of Java. We
 * good coders have been oppressed for too long by the lame language
 * decisions of pointy-haired bosses and academics who should know better. 
 * It's time we stand up against this junk, and bring back the fun in
 * programming! Viva La Revolution!
 */
#define aSet c
#define BufferedReader(x)1
#define byte Y[I][_^1]?do(:):_&1?do(.):do(`):8;++y;}
#define class int N=0,_,O=328,l=192,y=4,Y[80][64]={0},I;struct
#define do(c)a(#c "\b")
#define err c,c
#define getAllStrings(x));q()
#define if(x)b(#x)
#define IOException
#define line c
#define main(a)b(char*x){write(1,"033円[",2),null}main()
#define new
#define null a(x);}a(char*x){write(1,x,strlen(x));try;try;try;try;
#define out c,c
#define println(x)c
#define private int d(int
#define public short c;}c;typedef int BufferedReader;char*F="JF>:>FB;;BII";
#define return {return
#define static f(x){N=(N+x)%6,y--?f(0),f(1),f(4),f(1):++Y[(I=O+N[F]-66)
#define String
#define System c
#define this if(D):1,O=I,I/=16,l<_/32?if(B):l>_/32?if(A):2,l=_,_/=16,byte
#define throws
#define toArray(x)c
#define try for(;--c.c;)
#define void /16][(_=l+N[6+F]-66)/16]?O/=16,l/=32,O<I/16?if(C):O>I/16?this
#define while(k)if(2J),if(7;21H),f(0),f(4),f(4),if(H),/*
import java.io.*;
import java.util.*;
/**
 * A lame Java program.
 * @author J. Random Worker
 */
class LameJavaApp
{
 /** The infamous Long-Winded Signature From Hell. */
 public static void main(String[] args)
 throws IOException
 {
 /* Don't get me started on this. */
 BufferedReader reader =
 new BufferedReader(new FileReader(args[0]));
 /* What, this long incantation just to print a string? */
 System.err.println("Hello world!");
 /* At least this is sane. */
 String line;
 while ((line = reader.readLine()) != null)
 System.out.println(line.length());
 }
 /**
 * Method with a needlessly long name.
 * @param aSet a set (!)
 */
 private String[] getAllStrings(Set<String> aSet)
 {
 /*
 * This dance is needed even in J2SE 5, which has type
 * templates. It was worse before that.
 */
 return aSet.toArray(new String[0]);
 }
}

• qwr: Verbosity at its finest.

Answer 10

C++ in C

OK, so you are a C++ programmer, but are forced to use C? No problem, you just have to write some supplementary headers missing in C. For example, here's a valid Hello World program in C:

In the supplementary header file iostream, write:

#include <stdio.h>
#define using volatile int
#define namespace message
#define std = 0
#define message(x) printf("%s\n",x)
#define cout 0
#define endl 0

In file string, write

#define string

In file helloworld.c (your actual C code), write

#include <iostream>
#include <string>
using namespace std;
int main()
{
 string message("Hello world");
 cout << message << endl;
 return 0;
}

And when compiling helloworld.c with a C compiler, instruct the compiler to also look for <...> header files wherever you stored the files iostream and string, for example, if you are compiling with gcc and put the files iostream and string in the current directory, compile with

gcc helloworld.c -o helloworld -I.

Note: The volatile in header iostream is there to enable a warning-free compile even at maximum warning level (a read from a volatile variable is considered to have an effect).

• Mr Lister: This is a bit of code trolling, isn't it.
• celtschk: Well, the program does exactly what it appears to do, doesn't it?
• Kyle Strand: So much funnier and more impressive this way around than C in C++.
• R. Martinho Fernandes: What kind of compiler warns if you don't use volatile here, and what kind of warning?
• Mr Lister: @KyleStrand But the "C in C++" one is more in tune with the quote in the question. Real programmers program in C, even if they have a C++ compiler.

Answer 11

CQL - Caffeinated Query Language

(or "SQL on Caffeine")

This may have been somewhat overly ambitious. Here is an attempt to write SQL(ish) declarative code in CoffeeScript. This requires the ECMAScript 6 Proxy feature. You can test it in node with --harmony-proxies.

Let's set up a template for defining proxies. (Taken from Benvie's comment on this issue)

forward = (->
 _slice = Array.prototype.slice
 _bind = Function.prototype.bind
 _apply = Function.prototype.apply
 _hasOwn = Object.prototype.hasOwnProperty
 Forwarder = (target) ->
 @target = target
 this
 Forwarder.prototype =
 getOwnPropertyNames: -> Object.getOwnPropertyNames(@target)
 keys: -> Object.keys(@target)
 enumerate: ->
 i = 0
 keys = []
 for value of @target
 keys[i++] = value
 keys
 getPropertyDescriptor: (key) ->
 o = @target;
 while o
 desc = Object.getOwnPropertyDescriptor o, key
 if desc
 desc.configurable = true;
 return desc;
 o = Object.getPrototypeOf o
 getOwnPropertyDescriptor: (key) ->
 desc = Object.getOwnPropertyDescriptor @target, key
 if desc
 desc.configurable = true
 desc
 defineProperty: (key, desc) -> Object.defineProperty @target, key, desc
 get: (receiver, key) -> @target[key]
 set: (receiver, key, value) ->
 @target[key] = value;
 true
 has: (key) -> key of @target
 hasOwn: (key) -> _hasOwn.call @target, key
 delete: (key) ->
 delete @target[key]
 true
 apply: (receiver, args) -> _apply.call @target, receiver, args
 construct: (args) -> new (_bind.apply @target, [null].concat args);
 forward = (target, overrides) ->
 handler = new Forwarder target;
 for k of Object overrides
 handler[k] = overrides[k]
 if typeof target is 'function'
 return Proxy.createFunction handler,
 -> handler.apply this, _slice.call arguments,
 -> handler.construct _slice.call arguments
 else
 return Proxy.create handler, Object.getPrototypeOf Object target
 forward
)();

Now define a proxy object and some suspicious global variables and functions:

sql = forward {
 tables: {}
 finalize: ->
 if typeof @activeRows isnt 'function'
 @result = []
 for row in @activeRows
 @result.push (val for val, i in row when @activeTable.columns[i] in @activeColumns)
 delete @activeRows
 delete @activeColumns
 delete @activeTable
 run: (q) ->
 q.call(this)
 @finalize()
 result = @result
 delete @result
 if typeof result isnt 'function' then console.log result
 return result
}, {
 get: (o,name) ->
 if name of @target
 return @target[name];
 (args...) -> {
 name
 args
 }
}
int = Number
varchar = (l) -> String
TABLE = (x) -> x
INTO = (x) -> x
CREATE = (tableData) ->
 name = tableData.name
 table =
 columns: []
 column = tableData.args[0]
 table[column.name] = []
 table.columns.push(column.name)
 while column = column.args[1]
 table[column.name] = []
 table.columns.push(column.name)
 sql.tables[name] = table
 sql.result = "Created table '#{name}'"
INSERT = (table) -> sql.activeTable = sql.tables[table().name]
VALUES = (rows...) ->
 for row in rows
 for val, i in row
 column = sql.activeTable.columns[i]
 sql.activeTable[column].push val
 sql.result = "Inserted #{rows.length} rows"
FROM = (table) ->
 sql.activeTable = sql.tables[table().name]
SELECT = (columns...) ->
 sql.activeColumns = []
 for col in columns
 if typeof col is 'function'
 col = col()
 sql.activeColumns.push col.name
 sql.activeRows = []
 for val in sql.activeTable[sql.activeTable.columns[0]]
 sql.activeRows.push []
 for col in sql.activeTable.columns
 for val, i in sql.activeTable[col]
 sql.activeRows[i].push val
IN = (list) -> { op: 'in', list }
WHERE = (column) ->
 i = sql.activeTable.columns.indexOf(column.name)
 if column.args[0].op is 'in'
 list = column.args[0].list
 sql.activeRows = (row for row in sql.activeRows when row[i] in list)
 else
 console.log 'Not supported!'
ASC = 'asc'
DESC = 'desc'
BY = (x) -> x
ORDER = (column) ->
 i = sql.activeTable.columns.indexOf(column.name)
 order = if column.args[0] is sql.ASC then 1 else -1
 sql.activeRows.sort (a,b) ->
 if a[i] < b[i]
 return -order
 else if a[i] > b[i]
 return order
 else
 return 0

Well that was quite a lot of setup! But now we can do the following (input/output in a console style):

> sql.run ->
 CREATE TABLE @books(
 @title varchar(255),
 @author varchar(255),
 @year int
 );
Create Table 'books'
> sql.run ->
 INSERT INTO @books
 VALUES ['The C++ Programming Language', 'Bjarne Stroustrup', 1985],
 ['Effective C++', 'Scott Meyers', 1992],
 ['Exceptional C++', 'Herb Sutter', 2000],
 ['Effective STL', 'Scott Meyers', 2001];
Inserted 4 rows
> sql.run ->
 SELECT @title, @year FROM @books
 WHERE @author IN ['Bjarne Stroustrup', 'Scott Meyers']
 ORDER BY @year DESC;
[ [ 'Effective STL', 2001 ],
 [ 'Effective C++', 1992 ],
 [ 'The C++ Programming Language', 1985 ] ]

It's not an actual polyglot, but that's not really the point. I know that @ is used for variables in SQL, but I need all the @s for column and table names because I haven't found a way to proxy the global object (and I wouldn't be surprised if it's really not possible - and for a good reason).

I also changed some parentheses into brackets (in particular after VALUES and IN). Unfortunately, what I couldn't figure out at all is a way to allow normal conditionals like year > 2000, because they would evaluate to a boolean right away.

Still this looks a lot like SQL and is definitely more declarative than imperative/functional/object-oriented so it should qualify nicely for the question. I'm actually thinking if I polished the code a bit and supported a few more features, this could be a useful CoffeeScript module.

Anyway, this was fun! :)

For those not too familiar with CoffeeScript, the SQL queries compile to the following JavaScript:

sql.run(function() {
 return CREATE(
 TABLE(
 this.books(
 this.title(varchar(255), 
 this.author(varchar(255), 
 this.year(int)))
 )
 )
 );
});
sql.run(function() {
 INSERT(INTO(this.books));
 return VALUES([...], ['Effective C++', 'Scott Meyers', 1992], [...], [...]);
});
sql.run(function() {
 SELECT(this.title, this.year(FROM(this.books)));
 WHERE(this.author(IN(['Bjarne Stroustrup', 'Scott Meyers'])));
 return ORDER(BY(this.year(thisESC)));
});

• Ismael Miguel: That is quite a lot of setup, but does look good. I am not a CoffeeScript programmer, but it does look great. The @ in SQL is used for session variables.
• Martin Ender: I decided to make the keywords global now. Now there are only @s for column and table names.
• Ismael Miguel: Now it looks a lot like SQL! You did a nice work with this one!
• KRyan: I don’t care much for coffee, but this is awesome.
• Martin Ender: @tac thanks, but no I just hacked it together for this challenge. Funny coincidence: redoing this in a clean way and putting it on GitHub was on my list of potential/long-term coding projects until I removed it just this morning.

Answer 12

Visual Basic 6 (in JavaScript)

'; Main sub-routine \
'; function Main() { ' \
Sub Main() '
 ' Do not throw any errors... \
 On Error Resume Next '; MsgBox = alert
 ' Show a message box... \
 MsgBox(1 / 0) '
 ' Show errors again... \
 On Error GoTo 0 '
 ' Show another message box... '
 MsgBox("Hello")
 ' ' } ' \
End Sub '
Main()

It also works in VBScript.

• js1568: Clever. You don't even need most of the semicolons.
• Toothbrush: @js1568 Thank you! I've now removed the semi-colons that aren't needed.

Answer 13

Python and... nobody will guess (edit: dc)

Here is some valid python code, but actually the program is written in a very different language:

# Initialize systems 1 and 2
# frame 1, divergency speed and divergency latency
f1ds, f1dl, z1 = [2,2,0]
# frame 2, divergency speed and divergency latency
f2ds, f2dl, z2 = [4,4,1]
# Set the most relevant value of ax (detected by low-energy collision)
ax = 42.424242
# Initialize list of successive energy states
s = [17.98167, 21.1621, 34.1217218, 57.917182]
# Most common value for nz parameter
# TODO: check if value from the article of A. Einstein is better
nz = 10
if z2>nz or ax in s:
 ax += 6
 f1ds = 8
 f2ds = 16
 z1 = 4
 z2 = 9
f1dl += z1
f2dl += z2
# main loop, iterate over all energy states
# Warning: hit Ctrl-C if nuclear explosion occurs and adjust either z or nz
for k in s:
 z = nz + k
 f1dl = f1ds + f2dl * z - z1 + 3.14
 f2dl = f2ds + f1dl * z - z2 + 10
 if k > 10 or z-2 in s:
 nz += 0xac # hexadecimal coefficient found in famous article by E. Fermi

The code runs in both languages with no error.

The combination is very crazy; I would be happy to wait one day or two before telling which is the other language; please leave comments for guessing.

edit: The language was the stack-based language from dc. You may see here well-known keywords like for, if, or, in, but only the letters matter! The , which has no meaning in dc is turned to a register because the first time it appears is after the letter s (the same for :).

• Thomas Eding: Unless the code does the same thing in both languages, I suppose a language like Befunge could do the trick.
• Thomas Baruchel: OK, I edit the code in order to put the language I actually chose.

Answer 14

F# in C++

Rather unimaginative and nasty abuse of the preprocessor. I thought it'd be fun to alter C++ to look like a completely dissimilar language instead of using a few aliases to make it look like Java or PHP. I'm not really expecting this to garner a ton of upvotes, it's a just-for-fun entry.

#define let int
#define args ( int __, char* args[] ) { int ___ 
#define println printf(
#define exit "\n" ); return 0; }
#include <stdio.h>
let main args =
 println "F# is better than C++"
 exit

Try it here.

Sadly writing something to STDOUT is about all it can do, although I'm sure if someone threw enough witchcraft at it they could make it do more.

• Jwosty: For the last line to work in F#, it would either have to be exit 0 or just 0.

Answer 15

C++ allows you to write lisp-like code, with the InteLib library:

(L|DEFUN, ISOMORPHIC, (L|TREE1, TREE2),
 (L|COND, 
 (L|(L|ATOM, TREE1), (L|ATOM, TREE2)),
 (L|(L|ATOM, TREE2), NIL),
 (L|T, (L|AND,
 (L|ISOMORPHIC, (L|CAR, TREE1), 
 (L|CAR, TREE2)),
 (L|ISOMORPHIC, (L|CDR, TREE1), 
 (L|CDR, TREE2))
 )))).Evaluate();

cf. http://www.informatimago.com/articles/life-saver.html

• Jonathan Van Matre: Welcome! We ask users to flag their posts as Community Wiki when the answer is not their own work. (And give proper attribution, but you already did that, so thank you!)
• itsjeyd: Original or not, you got my vote :)

Answer 16

C# in Whitespace

Okay, first try at one of these, so let's see how it goes.

using System; //very important 
namespace ConsoleApplication1 //namespace: name whatever you want 
{ 
 //start 
 class Program //class name: also anything 
 {
 //main function 
 static void Main(string[] args) {
 for(int i=0;i<10;i++) writeOutput(i); 
 } //end main 
 static void writeOutput(int i) { Console.WriteLine(i); } //display output 
 } //class ends here 
} //close namespace: also very important 
//yay!

And in case the formatting went screwy from having to put four spaces at the front of each line, here it is again with . for space and # for tab:

using.System;.//very.important#
namespace.ConsoleApplication1..//namespace:#name.whatever.you.want##
{.
.//start#
.class#Program..//class.name:#also.anything#.
#{
....//main.function#
#static.void.Main(string[].args).{
....#for(int.i=0;i<10;i++)#writeOutput(i);#
#}.//end.main#
#static.void.writeOutput(int#i).{.Console.WriteLine(i);.}#//display.output#
.
.#}.//class.ends.here.##
}..//close.namespace:#also.very.important#.#
.
//yay!

Answer 17

HTML and CSS

Not programming languages, but ... this document is valid HTML and CSS:

<!-- p{color:red} /* -->
<!Doctype html>
<title>This is HTML and CSS</title>
<p>Hi!</p>
<!-- */ -->

<!-- p{color:red} /* -->
<!Doctype html>
<title>This is HTML and CSS</title>
<p>Hi!</p>
<!-- */ -->

This works, because HTML comments are allowed in stylesheets for historical reasons. Oh, and every valid HTML document is a valid PHP program too, so this is also PHP. :)

• Martin Ender: That's quite funny and all but this is not really a polyglot challenge.
• Adam Davis: Since CSS could be considered turing complete, this may be a valid answer.
• Jet: HTML and CSS are not programming languages :)

Answer 18

C in Scala

The bridging layer emulates a more romantic era when strings were still null terminated arrays of bytes.

// Scala is a dynamic language
import scala.language.{ dynamics, postfixOps }
val self = this
val argc = args.length
val argv = args.map(_.getBytes)
type char = Array[Byte]
object char extends Dynamic {
 // This program uses expanded memory
 val buffers = new scala.collection.mutable.LinkedHashMap[String, char]
 // Malloc char buffer
 def applyDynamic(name: String)(length: Int) =
 buffers(name) = new Array(length)
 def **(argv: Array[Array[Byte]]) = argv
}
object & extends Dynamic {
 // dereference char pointer
 def selectDynamic(name: String) = char.buffers(name)
}
def printf(format: String, buffers: char*) =
 println(
 (format /: buffers){ case (msg, buffer) =>
 // Read string until 0円 terminator
 val value = new String(buffer.takeWhile(0 !=))
 // Replace next %s token
 msg.replaceFirst("%s", value)
 }
 )
def scanf(format: String, buffers: char*) =
 buffers foreach { buffer =>
 val line = Console.readLine()
 // Write string to char* buffer
 line.getBytes(0, line.length, buffer, 0)
 // Remember to always null terminate your strings!
 buffer(line.length) = 0
 }
val PATH_MAX = 4096
implicit class Argumenter(args: Pair[_, _]) {
 def apply[T](f: => T) = f
}
object int {
 // Passthrough
 def main[T](f: => T) = f
 def argc = self.argc
}
// terminates the string after the first character
// investigate switching to "xor eax, eax" instead of having a hardcoded 0
// might save 3 bytes and valuable CPU time with this trick
val initialize = (_: char)(1) = 0
def exit(value: Int) = sys.exit(value)

// ---HOMEWORK-ASSIGNMENT-START---
int main(int argc, char **argv) {
 if (argc != 0) {
 printf("This program does not take parameters!");
 exit(1);
 }
 // I've copy pasted this code from somewhere
 // Code reuse is essential if we want to be DRY
 char first(PATH_MAX + 1);
 char last(PATH_MAX + 1);
 printf("Enter your first and last name:\n");
 scanf("%s%s", &first, &last);
 // Still learning references, do I need these here?
 // I've performed benchmarks on printf and I think it's faster this way
 printf("Your full name is %s %s", &first, &last);
 initialize(&first);
 printf("Your signature is %s. %s", &first, &last);
 exit(0);
}

• Erik the Outgolfer: "This program does not take parameters!" fooled ya

Answer 19

sed and APL

My boss wants me to write sed scripts, but I like rather writing APL all the day. Nevertheless, he is very happy with my job because such scripts run perfectly with his version of sed:

i ← g ← 42
a ← d ← 10
s/s←2⊤42/s←2⊤43/g
s/s[01]*1/s⊣1/g
g

You can try it on my new website with this permalink. It is a compiled to javascript version of GNU APL. Final release will be later with official release of GNU APL, v. 1.3 but you can perfectly use it for your permalinks if you enjoy GNU APL.

Answer 20

C in Haskell

import Foreign.C.String
import Foreign.C.Types
import Foreign.Marshal.Array
import Foreign.Ptr
import System.Environment
import System.Exit
-- The meat of the program
cmain :: (CInt, Ptr (Ptr CChar)) -> IO CInt
cmain(argc, argv) = do {
 putStr("hello, world\n");
 return 0;
}
-- Of course, the above function doesn't do anything unless we write a wrapper
-- around it. This could have been done more simply, using higher-level library
-- functions, but where's the fun in that?
main :: IO ()
main = do {
 args <- getArgs;
 argPtrs <- sequence [do {
 argPtr <- mallocArray0(length(arg)) :: IO (Ptr CChar);
 pokeArray0(0)(argPtr)(map(castCharToCChar)(arg));
 return argPtr;
 } | arg <- args ];
 argv <- mallocArray(length(argPtrs)) :: IO (Ptr (Ptr CChar));
 pokeArray(argv)(argPtrs);
 exitCode <- cmain(fromIntegral(length(args)),argv);
 if (exitCode == 0) then do {
 exitWith(ExitSuccess);
 } else do {
 exitWith(ExitFailure(fromIntegral(exitCode)));
 };
}

Of course, since cmain doesn't do anything with argc or argv, the argument-marshaling code has no effect, and since cmain always returns 0, the "else" branch of the "if" statement is dead. But the "if" statement doesn't do anything anyway.

All of the braces and semicolons are unnecessary, as are most of the parentheses and some of the do keywords. The "if" statement could have been written as if exitCode == 0 then exitWith ExitSuccess else exitWith (ExitFailure (fromIntegral exitCode)).

Answer 21

C++ in Forth

: #include ; : <iostream> ; : { ; : } ; : int ; : using ;
: namespace ; : std; ; : main() ; : cout ; : << ;
: "Hello, ; : world!\n"; S" Hello, world!" type ; : return ; : 0; ;
#include <iostream>
using namespace std;
int main() {
 cout << "Hello, world!\n";
}

Not the most flexible solution, but it works if written exactly as shown.

Answer 22

Haskell in Java

("vanilla" Java 7, not Java 8) (Yes, I know that boxing ruins performance; and even trying to use higher order functions gets crazy verbose :D)

Java has very rigid syntax, so instead of changing syntax I tried to make code semantically more similar to Haskell style.

Edit — added partial function application.

import java.util.Iterator;
interface Function1<A, B> {
 A call(B arg);
}
interface Function2<A, B, C> {
 A call(B arg1, C arg2);
}
class Reduce<A> implements Function2<A, Function2<A, A, A>, Iterable<A>> {
 @Override
 public A call(Function2<A, A, A> arg1, Iterable<A> arg2) {
 final Iterator<A> i = arg2.iterator();
 A r = i.next();
 while (i.hasNext())
 r = arg1.call(r, i.next());
 return r;
 }
}
class Range implements Iterable<Integer> {
 private final int min;
 private final int max;
 public Range(int min, int max) {
 this.min = min;
 this.max = max;
 }
 @Override
 public Iterator<Integer> iterator() {
 return new Iterator<Integer>() {
 int i = min;
 @Override
 public boolean hasNext() {
 return i <= max;
 }
 @Override
 public Integer next() {
 return i++;
 }
 @Override
 public void remove() {
 throw new UnsupportedOperationException();
 }
 };
 }
}
public class Main {
 public static <A, B, C> Function1<A, C> applyPartial(final Function2<A, B, C> f, final B arg2) {
 return new Function1<A, C>() {
 @Override
 public A call(C arg) {
 return f.call(arg2, arg);
 }
 };
 }
 public static void main(String[] args) {
 final Function1<Integer, Iterable<Integer>> product = applyPartial(new Reduce<Integer>(), new Function2<Integer, Integer, Integer>() {
 @Override
 public Integer call(Integer arg1, Integer arg2) {
 return arg1 * arg2;
 }
 });
 final Function1<Integer, Integer> fact = new Function1<Integer, Integer>() {
 @Override
 public Integer call(Integer arg) {
 return product.call(new Range(1, arg));
 }
 };
 final Integer x = fact.call(6);
 System.out.println(x.toString());
 }
}

(Yes, all that this madness does is computing 6!)

Answer 23

COBOL in AWK

In the spirit of the quote. Pure, unadulterated AWK, as it may be written by a COBOL programmer.

The task is to count the records on a file. This early development version is counting itself for testing. The correct file will be hard-coded later when released from Unit Testing...

If I could get the syntax highlighting to do phosphorescent-green on black, it would be great...

Even got the column-numbers correct on this one, that's seven blanks at the start of each line (never done that in awk before) and breaking the long print statements at column 72.

 BEGIN { 
 PERFORM_000_INITIALISATION() 
 PERFORM_100_OPEN_FILES() 
 PERFORM_200_PROCESS_FILE() 
 PERFORM_300_CLOSE_FILES() 
 PERFORM_400_SHOW_THE_COUNTS() 
 exit 
 } 
 function PERFORM_000_INITIALISATION() { 
 INPUT_FILE_NAME = "COBOL.AWK" 
 RECORD_COUNT = 0 
 } 
 function PERFORM_100_OPEN_FILES() { 
 } 
 function PERFORM_200_PROCESS_FILE() { 
 PERFORM_210_PRIMING_READ() 
 PERFORM_220_PROCESS_INPUT_UNTIL_END() 
 } 
 function PERFORM_300_CLOSE_FILES() { 
 } 
 function PERFORM_400_SHOW_THE_COUNTS() { 
 print "COBOL.AWK: NUMBER OF RECORDS READ IS " RECORD_COUNT 
 } 
 function PERFORM_210_PRIMING_READ() { 
 PERFORM_900_READ_THE_FILE() 
 if ( FILE_STATUS < 0 ) { 
 print "COBOL.AWK ERR0001: INVALID FILE, HALTING, FILE N" \
 "AME IS: " INPUT_FILE_NAME 
 exit 
 } 
 if ( FILE_STATUS == 0 ) { 
 print "COBOL.AWK ERR0002: NO RECORDS ON INPUT, HALTING," \
 "FILE NAME IS: " INPUT_FILE_NAME 
 exit 
 } 
 } 
 function PERFORM_220_PROCESS_INPUT_UNTIL_END() {
 while ( FILE_STATUS != 0 ) { 
 INPUT_RECORD = 0ドル 
 RECORD_COUNT = RECORD_COUNT + 1 
 PERFORM_900_READ_THE_FILE() 
 } 
 } 
 function PERFORM_900_READ_THE_FILE() { 
 FILE_STATUS = getline < INPUT_FILE_NAME 
 } 

Answer 24

SML in Java

I still have some ancient code around from when I started learning Java and tried to use it in a functional style. Slightly cleaned up:

/**
 * Genericised ML-style list.
 */
public class FunctionalList<T> 
{
 private final T head;
 private final FunctionalList<T> tail;
 public FunctionalList(T x, FunctionalList<T> xs) {
 this.head = x;
 this.tail = xs;
 }
 public static <T> FunctionalList<T> cons(T x, FunctionalList<T> xs) {
 return new FunctionalList<T>(x, xs);
 }
 public static <T> T hd(FunctionalList<T> l) {
 return l.head;
 }
 public static <T> FunctionalList<T> tl(FunctionalList<T> l) {
 return l.tail;
 }
 public static int length(FunctionalList<?> l) {
 return len(l, 0);
 }
 private static int len(FunctionalList<?> l, int n) {
 return l == null ? n : len(tl(l), n + 1);
 }
 public static <T> FunctionalList<T> rev(FunctionalList<T> l) {
 return rev(l, null);
 }
 private static <T> FunctionalList<T> rev(FunctionalList<T> a, FunctionalList<T> b) {
 return a == null ? b : rev(tl(a), cons(hd(a), b));
 }
 public static <T> FunctionalList<T> append(FunctionalList<T> a, FunctionalList<T> b) {
 return a == null ? b : cons(hd(a), append(tl(a), b));
 }
}

Answer 25

Java in Perl

May count as rule breaking, but I don't care. Obviously, it's intended to look like Java program. It prints 20 Fibonacci numbers, in case it isn't obvious.

Requires Inline::Java module to be installed.

use Inline Java => <<'JAVA';
/**
 * @author Konrad Borowski <[email protected]>
 * @version 0.1.0
 */
class Fibonacci
{
 /**
 * Responsible for storing the number before last generated number.
 */
 private long beforeLastNumber = 0;
 /**
 * Responsible for storing the last generated number.
 */
 private long lastNumber = 1;
 /**
 * Receives the next Fibonacci number.
 * 
 * @return long integer that is the next Fibonacci number
 */
 public long next()
 {
 long temponaryLastNumber = lastNumber;
 lastNumber = beforeLastNumber + lastNumber;
 beforeLastNumber = temponaryLastNumber;
 return temponaryLastNumber;
 }
 /**
 * Outputs the Fibonacci number to standard output.
 */
 public void printFibonacci()
 {
 System.out.println(next());
 }
 /**
 * Outputs the Fibonacci number to standard output given number of
 * times.
 * 
 * @param times number of times to print fibonacci number
 */
 public void printFibonacciTimes(int times)
 {
 int i;
 for (i = 0; i < times; i++) {
 printFibonacci();
 }
 }
 /**
 * Constructor for Fibonacci object. Does nothing.
 */
 public Fibonacci()
 {
 // Do nothing.
 }
}
JAVA
###
 # The executable class that shows 20 Fibonacci numbers.
 ##
package OutputFibonacci
{
 ###
 # Shows 20 Fibonacci numbers. This method is public,
 # static, and returns void.
 ##
 sub main()
 {
 # In Perl, -> is object method separator, not a dot. This is stupid.
 new Fibonacci()->printFibonacciTimes(20);
 }
}
# Perl doesn't automatically call main method.
OutputFibonacci::main();

Answer 26

Brainfuck (or anything else) in Racket

Racket's flexible module and macro system allows it to implement module support for entirely new languages, both domain-specific and general-purpose. There is out of the box support for both Datalog and Algol 60, so the following are both valid Racket programs:

#lang datalog
edge(a, b). edge(b, c). edge(c, d). edge(d, a).
path(X, Y) :- edge(X, Y).
path(X, Y) :- edge(X, Z), path(Z, Y).
path(X, Y)?
#lang algol60
begin
 integer procedure SIGMA(x, i, n);
 value n;
 integer x, i, n;
 begin
 integer sum;
 sum := 0;
 for i := 1 step 1 until n do
 sum := sum + x;
 SIGMA := sum;
 end;
 integer q;
 printnln(SIGMA(q*2-1, q, 7));
end

You can also add support for other languages: e.g. see Danny Yoo's description of how to implement support for Brainfuck, which permits Racket programs such as:

#lang planet dyoo/bf
++++++[>++++++++++++<-]>.
>++++++++++[>++++++++++<-]>+.
+++++++..+++.>++++[>+++++++++++<-]>.
<+++[>----<-]>.<<<<<+++[>+++++<-]>.
>>.+++.------.--------.>>+.

And since the support is added at the compiled module level, it's possible to link modules written in different languages or embed a snippet of one language inside a module written in another.

Answer 27

J and... nobody will guess (edit: dc)

This is my second entry; here is a piece of valid J code, which returns 1:

10 o. 1 r. 2 i. 4 [ ( 0:`1: @. (2&|)) ] 8 #: *:@+: 42

I am waiting one or two day before telling which is the other language running the very same piece of code with no error. Just leave comments for trying to guess.

edit: The other language is the stack-based language from the very ancient Unix calculator dc.

• Peter Taylor: It runs without errors in GolfScript, BF, HQ9+, ...
• Thomas Baruchel: OK, I wasn't aware that such many languages could do it. I edit the code in order to put the language I actually chose.
• Stack Exchange Broke The Law: @ברוכאל it runs without errors in those languages because those languages don't have errors, or don't have errors applicable to this code. Eg. Brainfuck ignores all characters that are not in .,+-<>[] so your program is equivalent to ...[.]+ in brainfuck which is a valid but pointless program. AFAIK a brainfuck program can only be invalid by having mismatched [].
• Thomas Baruchel: @immibis. This is false. dc is an old calculator and I can assure that changing one thing in my codes would raise an error. I spent much time on some parts of the code to figure out some tricky way of putting the letters in the right order. My piece of code Postscript/dc is quite extreme: no error but changing anything will make it faulty. dc has nothing to do with "those languages"; dc is about 20 or 30 years older than "those languages"; it is generally installed on any Linux distribution. Please, browse a little if you haven't heard about it.
• Stack Exchange Broke The Law: @ברוכאל you misunderstood - I was talking about brainfuck, HQ9+, golfscript, etc. - not dc.

Answer 28

dc running a PostScript file

dc can run the following piece of code with no error:

10 10 10 10 10 42 32 10 10
stop % first send a stop
0 0 srand rand
le pop pop 3.14 sin
lt 2 3 lt and pop
le 2 10 le xor
pop pop pop 1 0 0
<< /sox 2 >> [ exch begin sox end ] aload
3.14 floor

Answer 29

ML/(Strict) Haskell in Java

This is from an actual real project. It makes use of persistent immutable data structures and uses recursion even when not necessary. Actually, it's more like Kore (the language the project implements) in Java, but the style is basically the same as ML. But the philosophy of Kore is that the author shouldn't format his code, so none of the Java code is formatted either (it's autoformatted by eclipse).

drop n elements from a list:

 public static <T> List<T> drop(List<T> l, Integer n) {
 return n == 0 ? l : drop(l.cons().tail, n - 1);
 }

In ML/Haskell, where you'd pattern match to extract the head and tail, here you say list.cons().x and list.cons().tail.

insert an element in a list:

 public static <T> List<T> insert(List<T> l, Integer i, T x) {
 if (i == 0)
 return cons(x, l);
 return cons(l.cons().x, insert(l.cons().tail, i - 1, x));
 }

List is defined literally how the algebraic datatype would be defined. Here is a version with the eclipse-generated boilerplate removed:

public final class List<T> {
 public static final class Nil<T> {
 }
 public static final class Cons<T> {
 public final T x;
 public final List<T> tail;
 public Cons(T x, List<T> tail) {
 if (x == null)
 throw new RuntimeException("null head");
 if (tail == null)
 throw new RuntimeException("null tail");
 this.x = x;
 this.tail = tail;
 }
 }
 private final Nil<T> nil;
 private final Cons<T> cons;
 private List(Nil<T> nil, Cons<T> cons) {
 this.nil = nil;
 this.cons = cons;
 }
 public boolean isEmpty() {
 return nil != null;
 }
 public Nil<T> nil() {
 if (nil == null)
 throw new RuntimeException("not nil");
 return nil;
 }
 public Cons<T> cons() {
 if (cons == null)
 throw new RuntimeException("not cons");
 return cons;
 }
 public static <T> List<T> cons(Cons<T> cons) {
 if (cons == null)
 throw new RuntimeException("constructor received null");
 return new List<T>(null, cons);
 }
 public static <T> List<T> nil(Nil<T> nil) {
 if (nil == null)
 throw new RuntimeException("constructor received null");
 return new List<T>(nil, null);
 }
}

Here is a map data structure implemented in terms of a trie:

public final class Map<K, V> {
 private final Tree<Character, Optional<Pair<K, V>>> tree;
 // keys are sorted in reverse order so entrySet can use cons instead of append
 private final Comparer<Pair<Character, Tree<Character, Optional<Pair<K, V>>>>> comparer =
 new PairLeftComparer<Character, Tree<Character, Optional<Pair<K, V>>>>(
 new ReverseComparer<Character>(new CharacterComparer()));
 private Map(Tree<Character, Optional<Pair<K, V>>> tree) {
 this.tree = tree;
 }
 public static <K, V> Map<K, V> empty() {
 return new Map<K, V>(new Tree<Character, Optional<Pair<K, V>>>(
 OptionalUtils.<Pair<K, V>> nothing(),
 ListUtils
 .<Pair<Character, Tree<Character, Optional<Pair<K, V>>>>> nil()));
 }
 public Optional<V> get(K k) {
 Tree<Character, Optional<Pair<K, V>>> t = tree;
 for (char c : k.toString().toCharArray()) {
 Tree<Character, Optional<Pair<K, V>>> t2 = getEdge(t, c);
 if (t2 == null)
 return nothing();
 t = t2;
 }
 if (t.v.isNothing())
 return nothing();
 return some(t.v.some().x.y);
 }
 public Map<K, V> put(K k, V v) {
 return new Map<K, V>(put(tree, k.toString(), v, k));
 }
 private Tree<Character, Optional<Pair<K, V>>> put(
 Tree<Character, Optional<Pair<K, V>>> t, String s, V v, K k) {
 if (s.equals(""))
 return new Tree<Character, Optional<Pair<K, V>>>(some(Pair.pair(k, v)),
 t.edges);
 char c = s.charAt(0);
 Tree<Character, Optional<Pair<K, V>>> t2 = getEdge(t, c);
 if (t2 == null)
 return new Tree<Character, Optional<Pair<K, V>>>(
 t.v,
 sort(
 cons(
 pair(
 c,
 put(new Tree<Character, Optional<Pair<K, V>>>(
 OptionalUtils.<Pair<K, V>> nothing(),
 ListUtils
 .<Pair<Character, Tree<Character, Optional<Pair<K, V>>>>> nil()),
 s.substring(1), v, k)), t.edges), comparer));
 return new Tree<Character, Optional<Pair<K, V>>>(t.v, sort(
 replace(pair(c, put(t2, s.substring(1), v, k)), t.edges), comparer));
 }
 private List<Pair<Character, Tree<Character, Optional<Pair<K, V>>>>> replace(
 Pair<Character, Tree<Character, Optional<Pair<K, V>>>> edge,
 List<Pair<Character, Tree<Character, Optional<Pair<K, V>>>>> edges) {
 if (edges.cons().x.x.equals(edge.x))
 return cons(edge, edges.cons().tail);
 return cons(edges.cons().x, replace(edge, edges.cons().tail));
 }
 // I consider this O(1). There are a constant of 2^16 values of
 // char. Either way it's unusual to have a large amount of
 // edges since only ASCII chars are typically used.
 private Tree<Character, Optional<Pair<K, V>>> getEdge(
 Tree<Character, Optional<Pair<K, V>>> t, char c) {
 for (Pair<Character, Tree<Character, Optional<Pair<K, V>>>> p : iter(t.edges))
 if (p.x.equals(c))
 return p.y;
 return null;
 }
 public Map<K, V> delete(K k) {
 return new Map<K, V>(delete(tree, k.toString()).x);
 }
 private Pair<Tree<Character, Optional<Pair<K, V>>>, Boolean> delete(
 Tree<Character, Optional<Pair<K, V>>> t, String k) {
 if (k.equals(""))
 return pair(
 new Tree<Character, Optional<Pair<K, V>>>(
 OptionalUtils.<Pair<K, V>> nothing(), t.edges), t.edges.isEmpty());
 char c = k.charAt(0);
 Tree<Character, Optional<Pair<K, V>>> t2 = getEdge(t, c);
 if (t2 == null)
 return pair(t, false);
 Pair<Tree<Character, Optional<Pair<K, V>>>, Boolean> p =
 delete(t2, k.substring(1));
 List<Pair<Character, Tree<Character, Optional<Pair<K, V>>>>> edges = nil();
 for (Pair<Character, Tree<Character, Optional<Pair<K, V>>>> e : iter(t.edges))
 if (!e.x.equals(c))
 edges = cons(e, edges);
 if (!p.y)
 return pair(
 new Tree<Character, Optional<Pair<K, V>>>(t.v, cons(pair(c, p.x),
 edges)), false);
 boolean oneEdge = t.edges.cons().tail.isEmpty();
 return pair(new Tree<Character, Optional<Pair<K, V>>>(t.v, edges), oneEdge
 && t.v.isNothing());
 }
 public static class Entry<K, V> {
 public Entry(K k, V v) {
 this.k = k;
 this.v = v;
 }
 public final K k;
 public final V v;
 }
 public List<Entry<K, V>> entrySet() {
 return entrySet(ListUtils.<Entry<K, V>> nil(), tree);
 }
 private List<Entry<K, V>> entrySet(List<Entry<K, V>> l,
 Tree<Character, Optional<Pair<K, V>>> t) {
 if (!t.v.isNothing()) {
 Pair<K, V> p = t.v.some().x;
 l = cons(new Entry<K, V>(p.x, p.y), l);
 }
 for (Pair<Character, Tree<Character, Optional<Pair<K, V>>>> e : iter(t.edges))
 l = entrySet(l, e.y);
 return l;
 }
}

The types start to take up as much space as the code. For example, in put, the method has 302 characters of types and 343 characters of code (not counting space/newlines).

Answer 30

BASIC in Ruby

Implemented this long ago. The source is on GitHub. Inspired by a similar thing in Scala

Setup

#!/usr/bin/env ruby
if caller.empty? && ARGV.length > 0
 $file = ARGV[0]
else
 $file = caller.last.split(':').first
end
require 'pp'
class String
 def %(other)
 self + other.to_s
 end
end
class RBaysick
 @@variables = {}
 @@code = []
 @@line = 0
 def initialize(contents)
 $DONT_RUN = true # To avoid endless loops.
 contents.gsub!(/( |\()'([^\W]+)/, '1円:2円 ')
 contents.gsub!(/(^| |\()(:[^\W]+)/, '1円GET(2円)')
 contents.gsub!(/ IF (.*) THEN (.*)/, ' IF { 1円 }.THEN { GOTO 2円 }')
 contents.gsub!(/LET *\(([^ ]+) *:= *(.*)\)/, 'LET(1円) { 2円 }')
 contents.gsub!(/(LET|INPUT)(\(| )GET\(/, '1円2円(')
 contents.gsub!(/ \(/, '(')
 contents.gsub!(/^(\d+) (.*)$/, 'line(1円) { 2円 }')
# contents.gsub!(/(\)|\}|[A-Z]) ([A-Z]+)/, '1円.2円')
 contents.gsub!(/ END /, ' __END ')
 contents.gsub!(/^RUN/, '__RUN')
 puts contents if $DEBUG
 eval contents
 end
 def __RUN
 while @@line > -1
 puts "#{@@line}: #{@@code[@@line].inspect}" if $DEBUG
 unless @@code[@@line].nil?
 @@increment = true
 @@code[@@line].call
 next unless @@increment
 end
 @@line += 1
 end
 end
 class If < Struct.new(:value)
 def THEN
 yield if value
 end
 end
 def method_missing(name, *args)
 puts "Missing: #{name.to_s}(#{args.map(&:inspect).join(', ')})" if $DEBUG
 end
 def variables
 @@variables
 end
 def line(line, &block)
 @@code[line] = block
 end
 def add(line, cmd, *args)
 puts "DEBUG2: #{cmd.to_s}(#{args.map(&:inspect).join(', ')})" if $DEBUG
 @@code[line] = send(cmd, *args)
 end
 def IF
 ::RBaysick::If.new(yield)
 end
 def PRINT(str)
 puts "PRINT(#{str.inspect})" if $DEBUG
 puts str
 true
 end
 def LET(name, &block)
 puts "LET(#{name.inspect}, #{block.inspect})" if $DEBUG
 @@variables[name] = block.call
 end
 def GET(name)
 puts "GET(#{name.inspect}) #=> #{@@variables[name].inspect}" if $DEBUG
 @@variables[name]
 end
 def INPUT(name)
 puts "INPUT(#{name.inspect})" if $DEBUG
 LET(name) { $stdin.gets.chomp.to_i }
 end
 def ABS(val)
 puts "ABS(#{val.inspect}) #=> #{val.abs.inspect}" if $DEBUG
 val.abs
 end
 def GOTO(line)
 @@increment = false
 @@line = line
 end
 def __END
 exit
 end
end
RBaysick.new(open($file).read) unless $DONT_RUN || (0ドル != __FILE__)

BASIC code

#!./rbaysick.rb
10 PRINT "Welcome to Baysick Lunar Lander v0.0.1"
20 LET ('dist := 100)
30 LET ('v := 1)
40 LET ('fuel := 1000)
50 LET ('mass := 1000)
60 PRINT "You are a in control of a lunar lander."
70 PRINT "You are drifting towards the surface of the moon."
80 PRINT "Each turn you must decide how much fuel to burn."
90 PRINT "To accelerate enter a positive number, to decelerate a negative"
100 PRINT "Distance " % 'dist % "km, " % "Velocity " % 'v % "km/s, " % "Fuel " % 'fuel
110 INPUT 'burn
120 IF ABS('burn) <= 'fuel THEN 150
130 PRINT "You don't have that much fuel"
140 GOTO 100
150 LET ('v := 'v + 'burn * 10 / ('fuel + 'mass))
160 LET ('fuel := 'fuel - ABS('burn))
170 LET ('dist := 'dist - 'v)
180 IF 'dist > 0 THEN 100
190 PRINT "You have hit the surface"
200 IF 'v < 3 THEN 240
210 PRINT "Hit surface too fast (" % 'v % ")km/s"
220 PRINT "You Crashed!"
230 GOTO 250
240 PRINT "Well done"
250 END
RUN