factor/extra/variants/variants.factor

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Factor

! Copyright (C) 2009 Joe Groff.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors arrays classes classes.mixin classes.parser
classes.singleton classes.tuple classes.tuple.parser
classes.union combinators inverse kernel lexer macros make
parser quotations sequences slots splitting words ;
IN: variants
PREDICATE: variant-class < mixin-class "variant?" word-prop ;
M: variant-class initial-value*
class-members [ f f ] [
first dup word? [ t ] [ initial-value* ] if
] if-empty ;
: define-tuple-class-and-boa-word ( class superclass slots -- )
pick [ define-tuple-class ] dip
dup name>> "<" ">" surround create-word-in swap define-boa-word ;
: define-variant-member ( member -- class )
dup array? [ first3 pick [ define-tuple-class-and-boa-word ] dip ] [ dup define-singleton-class ] if ;
: define-variant-class ( class -- )
[ define-mixin-class ] [ t "variant?" set-word-prop ] bi ;
: define-variant-class-member ( class member -- )
define-variant-member swap add-mixin-instance ;
: define-variant-class-members ( class members -- )
[ dup define-variant-class ] dip
[ define-variant-class-member ] with each ;
: parse-variant-tuple-member ( name -- member )
create-class-in tuple
"{" expect
[ "}" parse-tuple-slots-delim ] { } make
3array ;
: parse-variant-member ( name -- member )
":" ?tail [ parse-variant-tuple-member ] [ create-class-in ] if ;
: parse-variant-members ( -- members )
[ scan-token dup ";" = not ]
[ parse-variant-member ] produce nip ;
SYNTAX: VARIANT:
scan-new-class
parse-variant-members
define-variant-class-members ;
SYNTAX: VARIANT-MEMBER:
scan-word
scan-token parse-variant-member
define-variant-class-member ";" expect ;
MACRO: unboa ( class -- quot )
<wrapper> \ boa [ ] 2sequence [undo] ;
GENERIC#: (match-branch) 1 ( class quot -- class quot' )
M: singleton-class (match-branch)
\ drop prefix ;
M: object (match-branch)
over \ unboa [ ] 2sequence prepend ;
: ?class ( object -- class )
dup word? [ class-of ] unless ;
MACRO: match ( branches -- quot )
[ dup callable? [ first2 (match-branch) 2array ] unless ] map
[ \ dup \ ?class ] dip \ case [ ] 4sequence ;