diff options
Diffstat (limited to 'module/c/eval/environment.scm')
-rw-r--r-- | module/c/eval/environment.scm | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/module/c/eval/environment.scm b/module/c/eval/environment.scm new file mode 100644 index 00000000..12eefaf7 --- /dev/null +++ b/module/c/eval/environment.scm @@ -0,0 +1,34 @@ +(define-module (c eval environment) + :use-module (srfi srfi-1) + :export (make-environment + env-set! env-ref push-frame! pop-frame!)) + +(define (make-frame) + (make-hash-table)) + +(define (make-environment) + (list (make-frame))) + +;; Returns an updated environment, linear update +(define (env-set! env key value) + ;; get handle to differentiate #f + ;; (even though #f should never be stored since it's not a C value) + (cond ((find (lambda (frame) (hashq-get-handle frame key)) env) + => (lambda (frame) (hashq-set! frame key value))) + (else (hashq-set! (car env) key value))) + env) + +(define (env-ref env key) + (cond ((null? env) + (scm-error 'misc-error "env-ref" + "~s unbound" + (list key) + #f)) + ((hashq-get-handle (car env) key) => cdr) + (else (env-ref (cdr env) key)))) + +(define (push-frame! environment) + (cons (make-frame) environment)) + +(define (pop-frame! environment) + (cdr environment)) |