diff options
| -rw-r--r-- | hw09.scm | 45 |
1 files changed, 39 insertions, 6 deletions
@@ -1,4 +1,9 @@ #lang eopl + +; Ben Burwell +; Dr. Kussmaul +; Programming Languages +; ; 4.3 INTERPRETER ; - this interpreter supports: ; - (3.x) expressions, bindings, procedures, recursion @@ -60,6 +65,15 @@ (type-exp ("bool") bool-type-exp) (type-exp (identifier) tid-type-exp) (type-exp ("(" (separated-list type-exp "*") "->" type-exp ")") proc-type-exp) + + ; (4.3) list stuffs + (primitive ("cons") cons-prim) + (primitive ("car") car-prim) + (primitive ("cdr") cdr-prim) + (primitive ("list") list-prim) + (primitive ("emptylist") empty-list-prim) + (primitive ("null?") null-prim) + )) ; ------------------------------------------------------------ @@ -76,7 +90,9 @@ ; named atomic type (atomic-type (name symbol?)) ; procedure type (parameter types and result type) - ( proc-type (arg-types (list-of type?)) (result-type type?)) ) + ( proc-type (arg-types (list-of type?)) (result-type type?)) + ( list-type (item-type type?) ) + ) ; primitive types (define int-type (atomic-type 'int )) @@ -172,7 +188,7 @@ (lambda (rands tenv) (map (lambda (expr) (type-of-expression expr tenv)) rands) )) - (define type-of-primitive +(define type-of-primitive (lambda (prim) (cases primitive prim ( add-prim () (proc-type (list int-type int-type) int-type)) @@ -180,7 +196,15 @@ (mult-prim () (proc-type (list int-type int-type) int-type)) (incr-prim () (proc-type (list int-type) int-type)) (decr-prim () (proc-type (list int-type) int-type)) - (zero-prim () (proc-type (list int-type) bool-type)) ))) + (zero-prim () (proc-type (list int-type) bool-type)) + + (cons-prim () 1) + (car-prim () 1) + (cdr-prim () 1) + (list-prim () 1) + (empty-list-prim () 1) + (null-prim () 1) + ))) (define type-of-proc-expr (lambda (texps ids body tenv) @@ -348,9 +372,11 @@ (lambda (ty) (cases type ty (atomic-type (name) name) - ( proc-type (arg-types result-type) + (proc-type (arg-types result-type) (append (arg-types-to-external-form arg-types) '(->) - (list (type-to-external-form result-type)) ))))) + (list (type-to-external-form result-type)) )) + (list-type (item-type) 'asdf) + ))) (define arg-types-to-external-form (lambda (types) @@ -400,7 +426,7 @@ ))) - (define eval-program +(define eval-program (lambda (prog) (cases program prog (stmt-prog (body) (eval-expression body (empty-env))) ))) @@ -426,6 +452,13 @@ (incr-prim () (+ (car args) 1)) (decr-prim () (- (car args) 1)) (zero-prim () (if (zero? (car args)) 1 0)) + + (cons-prim () (cons (car args) (cadr args))) + (car-prim () (car args)) + (cdr-prim () (cdr args)) + (list-prim () args) + (empty-list-prim () '()) + (null-prim () ((if (null? (args)) 1 0))) ))) ; ------------------------------------------------------------ |