factor/core/generic/math/math.factor

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Factor
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! Copyright (C) 2005, 2007 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: arrays generic hashtables kernel kernel.private
math namespaces sequences words quotations layouts combinators
sequences.private classes definitions ;
IN: generic.math
PREDICATE: class math-class ( object -- ? )
dup null bootstrap-word eq? [
drop f
] [
number bootstrap-word class<
] if ;
: last/first ( seq -- pair ) dup peek swap first 2array ;
: math-precedence ( class -- n )
{
{ [ dup class-empty? ] [ drop { -1 -1 } ] }
{ [ dup math-class? ] [ types last/first ] }
{ [ t ] [ drop { 100 100 } ] }
} cond ;
: math-class-max ( class class -- class )
[ [ math-precedence ] compare 0 > ] most ;
: (math-upgrade) ( max class -- quot )
dupd = [ drop [ ] ] [ "coercer" word-prop [ ] or ] if ;
: math-upgrade ( class1 class2 -- quot )
[ math-class-max ] 2keep
>r over r> (math-upgrade) >r (math-upgrade)
dup empty? [ [ dip ] curry [ ] like ] unless
r> append ;
ERROR: no-math-method left right generic ;
: default-math-method ( generic -- quot )
[ no-math-method ] curry [ ] like ;
: applicable-method ( generic class -- quot )
over method
[ 1quotation ]
[ default-math-method ] ?if ;
: object-method ( generic -- quot )
object bootstrap-word applicable-method ;
: math-method ( word class1 class2 -- quot )
2dup and [
2dup math-upgrade >r
math-class-max over order min-class applicable-method
r> prepend
] [
2drop object-method
] if ;
: math-vtable ( picker quot -- quot )
[
>r
, \ tag ,
num-tags get [ bootstrap-type>class ]
r> compose map ,
\ dispatch ,
] [ ] make ; inline
TUPLE: math-combination ;
M: math-combination make-default-method
drop default-math-method ;
M: math-combination perform-combination
drop
\ over [
dup math-class? [
\ dup [ >r 2dup r> math-method ] math-vtable
] [
over object-method
] if nip
] math-vtable nip ;
PREDICATE: generic math-generic ( word -- ? )
"combination" word-prop math-combination? ;
M: math-generic definer drop \ MATH: f ;