Quine

Quine is a programming puzzle. It lays out a problem which Rosetta Code users are encouraged to solve, using languages and techniques they know. Multiple approaches are not discouraged, so long as the puzzle guidelines are followed. For other Puzzles, see Category:Puzzles.

This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.

Print out a program's own source code without reading from the source file.

Ada

with Text_Io;
procedure Self is 
   Q:Character:='"';
   A:String(1..132):="with text_io;procedure self is q:character:=;a:string(1..132):=;begin text_io.put_line(a(1..45)&q&a(46..65)&q&a&q&a(66..132));end;"; begin 
   Text_Io.Put_Line(A(1..45)&Q&A(46..65)&Q&A&Q&A(66..132));
end;

Befunge

The code space is also the data space of a Befunge program. Programs can be read and modified on the fly. This quine works by reading and printing each character of the source. (This is a implicit loop, since the Befunge codespace wraps around.)

:0g,:66+`#@_1+

Forth

SOURCE TYPE

Haskell

The obvious solution, as a one-liner:

let q s = putStrLn $ s ++ show s in q "let q s = putStrLn $ s ++ show s in q "

Having the string at the end makes things a bit simpler than in generic version mentioned in the Wikipedia article.

Haskell does not keep the code in an uncompiled-equivalent form around at runtime, so the "quotation trick" has to be used.

LISP

The empty list is a valid LISP routine. Upon invocation it returns ... an empty list. Which is thus its own code:

()

This is bound to be one of the shortest quines in existence.

Seed7

$ include "seed7_05.s7i";
const array string: prog is [](
"$ include \"seed7_05.s7i\";",
"const array string: prog is [](",
"const proc: main is func",
"  local var integer: number is 0;",
"  begin",
"    for number range 1 to 2 do writeln(prog[number]); end for;",
"    for number range 1 to 11 do",
"      writeln(literal(prog[number]) <& \",\");",
"    end for;",
"    writeln(literal(prog[12]) <& \");\");",
"    for number range 3 to 12 do writeln(prog[number]); end for;",
"  end func;");
const proc: main is func
  local var integer: number is 0;
  begin
    for number range 1 to 2 do writeln(prog[number]); end for;
    for number range 1 to 11 do
      writeln(literal(prog[number]) <& ",");
    end for;
    writeln(literal(prog[12]) <& ");");
    for number range 3 to 12 do writeln(prog[number]); end for;
  end func;

Original source: [1]