7491e172ea
The eopl language is now racket-based rather than mzscheme-based. This test-suite, which was originally distributed on the book's web-site has been re-written in the new language. Changes include dropping all drscheme-init.scm and top.scm files. Remaining files were renamed to use the .rkt extension and edited to use the #lang syntax (instead of modulue). Require and provide forms were changed to reflect racket's syntax instead of mzscheme's (eg, only-in vs. only). Several occurrences of one-armed ifs were changed to use when and unless. All tests have been run successfully.
117 lines
4.0 KiB
Racket
Executable File
117 lines
4.0 KiB
Racket
Executable File
#lang eopl
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(require "cps-out-lang.rkt")
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(require "data-structures.rkt") ; this includes environments
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(provide value-of-program value-of/k)
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;;;;;;;;;;;;;;;; the interpreter ;;;;;;;;;;;;;;;;
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;; value-of-program : Program -> ExpVal
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(define value-of-program
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(lambda (pgm)
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(cases cps-out-program pgm
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(cps-a-program (exp1)
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(value-of/k exp1 (init-env) (end-cont))))))
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(define value-of-simple-exp
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(lambda (exp env)
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(cases simple-expression exp
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(cps-const-exp (num) (num-val num))
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(cps-var-exp (var) (apply-env env var))
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(cps-diff-exp (exp1 exp2)
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(let ((val1
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(expval->num
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(value-of-simple-exp exp1 env)))
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(val2
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(expval->num
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(value-of-simple-exp exp2 env))))
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(num-val
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(- val1 val2))))
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(cps-zero?-exp (exp1)
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(bool-val
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(zero?
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(expval->num
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(value-of-simple-exp exp1 env)))))
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(cps-sum-exp (exps)
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(let ((nums (map
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(lambda (exp)
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(expval->num
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(value-of-simple-exp exp env)))
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exps)))
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(num-val
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(let sum-loop ((nums nums))
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(if (null? nums) 0
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(+ (car nums) (sum-loop (cdr nums))))))))
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(cps-proc-exp (vars body)
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(proc-val
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(procedure vars body env)))
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)))
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;; value-of/k : TfExp * Env * Cont -> FinalAnswer
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;; Page: 209
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(define value-of/k
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(lambda (exp env cont)
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(cases tfexp exp
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(simple-exp->exp (simple)
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(apply-cont cont
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(value-of-simple-exp simple env)))
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(cps-let-exp (var rhs body)
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(let ((val (value-of-simple-exp rhs env)))
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(value-of/k body
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(extend-env* (list var) (list val) env)
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cont)))
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(cps-letrec-exp (p-names b-varss p-bodies letrec-body)
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(value-of/k letrec-body
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(extend-env-rec** p-names b-varss p-bodies env)
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cont))
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(cps-if-exp (simple1 body1 body2)
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(if (expval->bool (value-of-simple-exp simple1 env))
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(value-of/k body1 env cont)
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(value-of/k body2 env cont)))
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(cps-call-exp (rator rands)
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(let ((rator-proc
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(expval->proc
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(value-of-simple-exp rator env)))
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(rand-vals
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(map
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(lambda (simple)
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(value-of-simple-exp simple env))
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rands)))
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(apply-procedure/k rator-proc rand-vals cont))))))
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;; apply-cont : Cont * ExpVal -> Final-ExpVal
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;; there's only one continuation, and it only gets invoked once, at
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;; the end of the computation.
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(define apply-cont
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(lambda (cont val)
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(cases continuation cont
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(end-cont () val))))
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;; apply-procedure/k : Proc * ExpVal * Cont -> ExpVal
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;; Page: 209
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(define apply-procedure/k
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(lambda (proc1 args cont)
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(cases proc proc1
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(procedure (vars body saved-env)
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(value-of/k body
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(extend-env* vars args saved-env)
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cont)))))
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'(define apply-procedure/k
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(lambda (proc1 args cont)
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(cases proc proc1
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(procedure (vars body saved-env)
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(value-of/k body
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(extend-env* vars args saved-env)
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cont)))))
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;; trace has to be in the module where the procedure is defined.
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;; (trace value-of/k apply-cont)
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