From: Ramakrishnan Muthukrishnan Date: Mon, 2 Jan 2012 08:57:24 +0000 (+0530) Subject: - More functions like =, >, < from underlying scheme X-Git-Url: https://git.rkrishnan.org/about.html?a=commitdiff_plain;h=03d0045f488976542f0aa744d1ddedd2ed287d6e;p=sicp.git - More functions like =, >, < from underlying scheme - renamed setup-environment to make-environment --- diff --git a/src/sicp/metacircular2.rkt b/src/sicp/metacircular2.rkt index 06209d3..83d89fa 100644 --- a/src/sicp/metacircular2.rkt +++ b/src/sicp/metacircular2.rkt @@ -61,7 +61,7 @@ (define (lookup-variable-value var env) (if (eq? env the-empty-environment) - (error "unbound variable:" var) + (error "unbound variable: " var) (let ([frame (first-frame env)]) (let ([value (hash-ref frame var (lambda () (lookup-variable-value var (enclosing-environment env))))]) (if (eq? value '*unassigned*) @@ -70,7 +70,7 @@ (define (set-variable-value! var val env) (if (eq? env the-empty-environment) - (error "unbound variable") + (error "unbound variable: " var) (let ([frame (first-frame env)]) (if (hash-has-key? frame var) (hash-set! frame var val) @@ -95,7 +95,9 @@ (list '- -) (list '* *) (list '/ /) - (list '= =))) + (list '= =) + (list '> >) + (list '< <))) (define (primitive-procedure-names) (map car primitive-procedures)) @@ -109,7 +111,7 @@ (primitive-implementation proc) args)) ;; global env -(define (setup-environment) +(define (make-environment) (let ((initial-env (extend-environment (primitive-procedure-names) (primitive-procedure-objects) @@ -118,7 +120,7 @@ (define-variable! 'false false initial-env) initial-env)) -(define the-global-environment (setup-environment)) +(define the-global-environment (make-environment)) ;; application (define (list-of-values exps env)