28 lines
918 B
Factor
28 lines
918 B
Factor
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#! An interpreter for lambda expressions, by Matthew Willis
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USING: io strings hashtables sequences namespaces kernel ;
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IN: lambda
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: lambda-print ( name/expr -- )
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dup string?
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[ dup lambda-names get hash expr>string " " swap
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append append "DEF " swap append
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] [ expr>string "=> " swap append
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] if print flush ;
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: lambda-define ( parse-result -- name/expr )
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#! Make sure not to evaluate definitions.
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first2 over [ over lambda-names get set-hash ] [ nip ] if ;
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: lambda-eval ( name/expr -- name/expr )
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dup string? [ normalize ] unless ;
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: lambda-boot ( -- )
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#! load the core lambda library
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H{ } clone lambda-names set lambda-core
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[ lambda-parse lambda-define lambda-eval lambda-print ] each ;
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: lambda ( -- )
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lambda-names get [ lambda-boot ] unless
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readln dup "." = [ drop ] [
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lambda-parse lambda-define lambda-eval lambda-print lambda
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] if ;
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