Tuesday, February 05, 2008

A Third Order Quine in Three Languages

Suppose Fnxy is a program, written in language x, that takes as input n string arguments as input, G1,...,Gn and outputs a program in language y that is the application of the function whose source code is G2 to the strings G2,G3,...,Gn,G1. Then F3xy(F3xy,F3yz,F3zx) will be a program in language x that that outputs a program in y that computes F3yz(F3yz,F3zx,F3xy).

We can put this into practice:


q a b c=putStrLn $ b ++ [toEnum 10,'q','('] ++ show b ++ [','] ++ show c ++ [','] ++ show a ++ [')']
main=q "q a b c=putStrLn $ b ++ [toEnum 10,'q','('] ++ show b ++ [','] ++ show c ++ [','] ++ show a ++ [')']" "def q(a,b,c):print b+chr(10)+'q('+repr(b)+','+repr(c)+','+repr(a)+')'" "def e(x) return 34.chr+x+34.chr end;def q(a,b,c) print b+10.chr+'main=q '+e(b)+' '+e(c)+' '+e(a)+' '+10.chr end"


This is a Haskell program that outputs a Python program that outputs a Ruby program that outputs the original Haskell program.

Apologies for the lack of line breaks. If it's not readable, it should be possible to copy and paste that source. Also, you may need to tweak it if your OS doesn't treat character 10 as a new line.

Labels: , ,

15 Comments:

OpenID cypher said...

That is awesome.

Wednesday, 06 February, 2008  
Blogger Nikolay said...

[15:27 /]$ ghci
___ ___ _
/ _ \ /\ /\/ __(_)
/ /_\// /_/ / / | | GHC Interactive, version 6.6.1, for Haskell 98.
/ /_\\/ __ / /___| | http://www.haskell.org/ghc/
\____/\/ /_/\____/|_| Type :? for help.

Prelude> q a b c=putStrLn $ b ++ [toEnum 10,'q','('] ++ show b ++ [','] ++ show c ++ [','] ++ show a ++ [')']
< interactive >:1:7: parse error on input `='

Wednesday, 06 February, 2008  
Anonymous Anonymous said...

Impressive O_O

Wednesday, 06 February, 2008  
Blogger Brent said...

nice!

Nikolay: you won't be able to just paste it into ghci like that, you'll have to put it in a file and then load the file into ghci.

Wednesday, 06 February, 2008  
Anonymous mzz said...

nikolay:
Write it into .hs file and use runhaskell to execute it.
ghci expects let before name bindings to distinguish them from expressions.

Wednesday, 06 February, 2008  
Blogger Nikolay said...

Ooh, I see. Thanks! It is really awesome!

Wednesday, 06 February, 2008  
Anonymous jk said...

Wow! That is really awesome.

Friday, 08 February, 2008  
Anonymous Anonymous said...

Wow! You're all dorks

Wednesday, 13 February, 2008  
Anonymous Anonymous said...

Amazing :)

Wednesday, 19 March, 2008  
Anonymous Anonymous said...

...please where can I buy a unicorn?

Wednesday, 16 December, 2009  
Blogger paurullan said...

Gorgeous!

Wednesday, 31 March, 2010  
Blogger Paul Hobbs said...

This is so fascinating! You are awesome =]

Monday, 20 September, 2010  
Blogger SteelToad said...

What this really needs is a recursive function

Tuesday, 25 January, 2011  
Anonymous Anonymous said...

it formatted my pr0n.

Tuesday, 25 January, 2011  
Anonymous Anonymous said...

runhaskell 3quine |python|ruby|diff 3quine -


*blinks*
*awe*

Wednesday, 26 January, 2011  

Post a Comment

Links to this post:

Create a Link

<< Home