103 lines
2.3 KiB
Scheme
Executable File
103 lines
2.3 KiB
Scheme
Executable File
(module lang (lib "eopl.ss" "eopl")
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;; language for MUTABLE-PAIRS
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(require "drscheme-init.scm")
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(provide (all-defined))
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;;;;;;;;;;;;;;;; grammatical specification ;;;;;;;;;;;;;;;;
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(define the-lexical-spec
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'((whitespace (whitespace) skip)
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(comment ("%" (arbno (not #\newline))) skip)
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(identifier
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(letter (arbno (or letter digit "_" "-" "?")))
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symbol)
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(number (digit (arbno digit)) number)
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(number ("-" digit (arbno digit)) number)
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))
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(define the-grammar
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'((program (expression) a-program)
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(expression (number) const-exp)
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(expression
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("-" "(" expression "," expression ")")
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diff-exp)
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(expression
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("zero?" "(" expression ")")
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zero?-exp)
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(expression
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("if" expression "then" expression "else" expression)
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if-exp)
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(expression (identifier) var-exp)
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(expression
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("let" identifier "=" expression "in" expression)
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let-exp)
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(expression
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("proc" "(" identifier ")" expression)
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proc-exp)
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(expression
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("(" expression expression ")")
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call-exp)
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(expression
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("letrec"
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(arbno identifier "(" identifier ")" "=" expression)
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"in" expression)
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letrec-exp)
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(expression
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("begin" expression (arbno ";" expression) "end")
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begin-exp)
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(expression
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("set" identifier "=" expression)
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assign-exp)
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;; new for mutable-pairs
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(expression
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("newpair" "(" expression "," expression ")")
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newpair-exp)
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(expression
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("left" "(" expression ")")
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left-exp)
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(expression
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("setleft" expression "=" expression)
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setleft-exp)
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(expression
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("right" "(" expression ")")
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right-exp)
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(expression
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("setright" expression "=" expression)
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setright-exp)
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))
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;;;;;;;;;;;;;;;; sllgen boilerplate ;;;;;;;;;;;;;;;;
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(sllgen:make-define-datatypes the-lexical-spec the-grammar)
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(define show-the-datatypes
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(lambda () (sllgen:list-define-datatypes the-lexical-spec the-grammar)))
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(define scan&parse
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(sllgen:make-string-parser the-lexical-spec the-grammar))
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(define just-scan
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(sllgen:make-string-scanner the-lexical-spec the-grammar))
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)
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