factor/basis/json/writer/writer.factor

! Copyright (C) 2006 Chris Double.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors kernel io.streams.string io strings splitting
sequences math math.parser assocs classes words namespaces make
prettyprint hashtables mirrors tr json ;
IN: json.writer

#! Writes the object out to a stream in JSON format
GENERIC: json-print ( obj -- )

: >json ( obj -- string )
    #! Returns a string representing the factor object in JSON format
    [ json-print ] with-string-writer ;

M: f json-print ( f -- )
    drop "false" write ;

M: t json-print ( t -- )
    drop "true" write ;

M: json-null json-print ( null -- )
    drop "null" write ;

M: string json-print ( obj -- )
    CHAR: " write1 "\"" split "\\\"" join CHAR: \r swap remove "\n" split "\\r\\n" join write CHAR: " write1 ;

M: integer json-print ( num -- )
    number>string write ;

M: real json-print ( num -- )
    >float number>string write ;

M: sequence json-print ( array -- ) 
    CHAR: [ write1 [ >json ] map "," join write CHAR: ] write1 ;

TR: jsvar-encode "-" "_" ;
  
: tuple>fields ( object -- seq )
    <mirror> [
        [ swap jsvar-encode >json % " : " % >json % ] "" make
    ] { } assoc>map ;

M: tuple json-print ( tuple -- )
    CHAR: { write1 tuple>fields "," join write CHAR: } write1 ;

M: hashtable json-print ( hashtable -- )
    CHAR: { write1 
    [ [ swap jsvar-encode >json % CHAR: : , >json % ] "" make ]
    { } assoc>map "," join write 
    CHAR: } write1 ;

M: word json-print name>> json-print ;