47 lines
1.1 KiB
Factor
47 lines
1.1 KiB
Factor
! Copyright (C) 2004, 2005 Slava Pestov.
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! See http://factor.sf.net/license.txt for BSD license.
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IN: inference
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USING: generic kernel lists namespaces sequences unparser words ;
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GENERIC: value= ( literal value -- ? )
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TUPLE: value recursion safe? ;
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C: value ( recursion -- value )
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[ t swap set-value-safe? ] keep
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[ set-value-recursion ] keep ;
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M: value = eq? ;
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TUPLE: computed ;
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C: computed ( -- value )
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recursive-state get <value> over set-delegate ;
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M: computed value= ( literal value -- ? )
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2drop f ;
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TUPLE: literal value ;
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C: literal ( obj rstate -- value )
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[ >r <value> r> set-delegate ] keep
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[ set-literal-value ] keep ;
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M: literal value= ( literal value -- ? )
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literal-value = ;
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: >literal< ( literal -- rstate obj )
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dup value-recursion swap literal-value ;
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M: value literal-value ( value -- )
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"A literal value was expected where a computed value was found"
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inference-error ;
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TUPLE: meet values ;
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C: meet ( values -- value )
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[ set-meet-values ] keep f <value> over set-delegate ;
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PREDICATE: tuple safe-literal ( obj -- ? )
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dup literal? [ value-safe? ] [ drop f ] ifte ;
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