factor/library/generic/tuple.factor

135 lines
3.8 KiB
Factor

! Copyright (C) 2005 Slava Pestov.
! See http://factor.sf.net/license.txt for BSD license.
IN: generic
USING: errors hashtables kernel kernel-internals lists math
namespaces parser sequences strings vectors words ;
! Tuples are really arrays in the runtime, but with a different
! type number. The layout is as follows:
! slot 0 - object header with type number (as usual)
! slot 1 - length, including class/delegate slots
! slot 2 - the class, a word
! slot 3 - the delegate tuple, or f
: class ( object -- class )
dup tuple? [ 2 slot ] [ type type>class ] ifte ; inline
: class-tuple ( object -- class )
dup tuple? [ 2 slot ] [ drop f ] ifte ; inline
: tuple-predicate ( word -- )
#! Make a foo? word for testing the tuple class at the top
#! of the stack.
dup predicate-word
[ \ class-tuple , over literalize , \ eq? , ] [ ] make
define-predicate ;
: forget-tuple ( class -- )
dup forget "predicate" word-prop car [ forget ] when* ;
: check-shape ( word slots -- )
#! If the new list of slots is different from the previous,
#! forget the old definition.
>r "in" get lookup dup [
dup "tuple-size" word-prop r> length 2 + =
[ drop ] [ forget-tuple ] ifte
] [
r> 2drop
] ifte ;
: delegate-slots { { 3 delegate set-delegate } } ;
: tuple-slots ( tuple slots -- )
2dup "slot-names" set-word-prop
2dup length 2 + "tuple-size" set-word-prop
dupd 4 simple-slots
2dup delegate-slots swap append "slots" set-word-prop
define-slots ;
: tuple-constructor ( class -- word )
word-name "in" get constructor-word dup save-location ;
: define-constructor ( word class def -- )
>r [
dup literalize , "tuple-size" word-prop , \ make-tuple ,
] [ ] make r> append define-compound ;
: default-constructor ( tuple -- )
[ tuple-constructor ] keep dup [
"slots" word-prop 1 swap tail-slice reverse-slice
[ peek unit , \ keep , ] each
] [ ] make define-constructor ;
: define-tuple ( tuple slots -- )
2dup check-shape
>r create-in
dup intern-symbol
dup tuple-predicate
dup tuple "superclass" set-word-prop
dup tuple "metaclass" set-word-prop
dup r> tuple-slots
default-constructor ;
! A sequence of all slots in a tuple, used for equality testing.
TUPLE: mirror tuple ;
C: mirror ( tuple -- mirror )
over tuple? [ "Not a tuple" throw ] unless
[ set-mirror-tuple ] keep ;
M: mirror nth ( n mirror -- elt )
bounds-check mirror-tuple array-nth ;
M: mirror set-nth ( n mirror -- elt )
bounds-check mirror-tuple set-array-nth ;
M: mirror length ( mirror -- len )
mirror-tuple array-capacity ;
: literal-tuple ( seq -- tuple )
dup first "tuple-size" word-prop <tuple>
[ <mirror> 0 swap rot copy-into ] keep ;
: clone-tuple ( tuple -- tuple )
#! Make a shallow copy of a tuple, without cloning its
#! delegate.
[ array-capacity <tuple> dup ] keep copy-array ;
M: tuple clone ( tuple -- tuple )
#! Clone a tuple and its delegate.
clone-tuple dup delegate clone over set-delegate ;
M: tuple hashcode ( vec -- n )
#! If the capacity is two, then all we have is the class
#! slot and delegate.
dup array-capacity 2 number= [
drop 0
] [
2 swap array-nth hashcode
] ifte ;
M: tuple = ( obj tuple -- ? )
2dup eq? [
2drop t
] [
over tuple? [
swap <mirror> swap <mirror> sequence=
] [
2drop f
] ifte
] ifte ;
tuple [ 2drop f ] "class<" set-word-prop
PREDICATE: word tuple-class metaclass tuple = ;
: is? ( obj pred -- ? | pred: obj -- ? )
#! Tests if the object satisfies the predicate, or if
#! it delegates to an object satisfying it.
[ call ] 2keep rot [
2drop t
] [
over [ >r delegate r> is? ] [ 2drop f ] ifte
] ifte ; inline