72 lines
1.8 KiB
Factor
72 lines
1.8 KiB
Factor
! Copyright (C) 2009 John Benediktsson
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! See http://factorcode.org/license.txt for BSD license
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USING: accessors assocs fry io io.streams.string kernel macros math
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peg.ebnf quotations sequences strings ;
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IN: brainfuck
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<PRIVATE
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TUPLE: brainfuck pointer memory ;
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: <brainfuck> ( -- brainfuck )
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0 H{ } clone brainfuck boa ;
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: get-memory ( brainfuck -- brainfuck value )
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dup [ pointer>> ] [ memory>> ] bi at 0 or ;
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: set-memory ( brainfuck value -- brainfuck )
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over [ pointer>> ] [ memory>> ] bi set-at ;
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: (+) ( brainfuck -- brainfuck )
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get-memory 1 + 255 bitand set-memory ;
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: (-) ( brainfuck -- brainfuck )
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get-memory 1 - 255 bitand set-memory ;
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: (?) ( brainfuck -- brainfuck t/f )
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get-memory 0 = not ;
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: (.) ( brainfuck -- brainfuck )
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get-memory 1string write ;
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: (,) ( brainfuck -- brainfuck )
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read1 set-memory ;
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: (>) ( brainfuck -- brainfuck )
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[ 1 + ] change-pointer ;
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: (<) ( brainfuck -- brainfuck )
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[ 1 - ] change-pointer ;
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: compose-all ( seq -- quot )
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[ ] [ compose ] reduce ;
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EBNF: parse-brainfuck
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inc-ptr = ">" => [[ [ (>) ] ]]
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dec-ptr = "<" => [[ [ (<) ] ]]
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inc-mem = "+" => [[ [ (+) ] ]]
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dec-mem = "-" => [[ [ (-) ] ]]
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output = "." => [[ [ (.) ] ]]
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input = "," => [[ [ (,) ] ]]
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space = (" "|"\t"|"\r\n"|"\n") => [[ [ ] ]]
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unknown = (.) => [[ "Invalid input" throw ]]
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ops = inc-ptr | dec-ptr | inc-mem | dec-mem | output | input | space
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loop = "[" {loop|ops}* "]" => [[ second compose-all 1quotation [ [ (?) ] ] prepend [ while ] append ]]
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code = (loop|ops|unknown)* => [[ compose-all ]]
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;EBNF
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PRIVATE>
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MACRO: run-brainfuck ( code -- )
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[ <brainfuck> ] swap parse-brainfuck [ drop flush ] 3append ;
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: get-brainfuck ( code -- result )
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[ run-brainfuck ] with-string-writer ; inline
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