105 lines
3.4 KiB
Factor
105 lines
3.4 KiB
Factor
! :folding=indent:collapseFolds=1:
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! $Id$
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!
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! Copyright (C) 2004 Slava Pestov.
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!
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! Redistribution and use in source and binary forms, with or without
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! modification, are permitted provided that the following conditions are met:
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!
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! 1. Redistributions of source code must retain the above copyright notice,
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! this list of conditions and the following disclaimer.
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!
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! 2. Redistributions in binary form must reproduce the above copyright notice,
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! this list of conditions and the following disclaimer in the documentation
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! and/or other materials provided with the distribution.
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!
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! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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IN: generic
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USE: errors
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USE: hashtables
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USE: kernel
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USE: lists
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USE: namespaces
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USE: parser
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USE: strings
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USE: words
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USE: vectors
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! Traits metaclass for user-defined classes based on hashtables
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: traits ( object -- symbol )
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dup hashtable? [ \ traits swap hash ] [ drop f ] ifte ;
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! Hashtable slot holding an optional delegate. Any undefined
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! methods are called on the delegate. The object can also
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! manually pass any methods on to the delegate.
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SYMBOL: delegate
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: traits-dispatch ( object selector -- object quot )
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over traits over "methods" word-property hash* dup [
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nip cdr ( method is defined )
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] [
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drop delegate rot hash [
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swap traits-dispatch ( check delegate )
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] [
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[ undefined-method ] ( no delegate )
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] ifte*
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] ifte ;
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: add-traits-dispatch ( word vtable -- )
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>r unit [ car traits-dispatch call ] cons \ hashtable r>
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set-vtable ;
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\ traits [
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( generic vtable definition class -- )
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2drop add-traits-dispatch
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] "add-method" set-word-property
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\ traits [
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drop hashtable "builtin-type" word-property unit
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] "builtin-supertypes" set-word-property
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\ traits 10 "priority" set-word-property
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\ traits [ 2drop t ] "class<" set-word-property
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: traits-predicate ( word -- )
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#! foo? where foo is a traits type tests if the top of stack
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#! is of this type.
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dup predicate-word swap
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[ swap traits eq? ] cons
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define-compound ;
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: TRAITS:
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#! TRAITS: foo creates a new traits type. Instances can be
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#! created with <foo>, and tested with foo?.
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CREATE
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dup define-symbol
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dup \ traits "metaclass" set-word-property
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traits-predicate ; parsing
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: constructor-word ( word -- word )
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word-name "<" swap ">" cat3 "in" get create ;
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: define-constructor ( constructor traits definition -- )
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>r
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[ \ traits pick set-hash ] cons \ <namespace> swons
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r> append define-compound ;
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: C: ( -- constructor traits [ ] )
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#! C: foo ... begins definition for <foo> where foo is a
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#! traits type.
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scan-word [ constructor-word ] keep
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[ define-constructor ] [ ] ; parsing
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