From f50cecf2cb77cc073cb86a6016468a09d1c49fb0 Mon Sep 17 00:00:00 2001 From: Ben Sima Date: Sat, 23 Mar 2019 23:58:26 -0700 Subject: Add semi-working bs --- lore/sicp/meta.scm | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 lore/sicp/meta.scm (limited to 'lore/sicp/meta.scm') diff --git a/lore/sicp/meta.scm b/lore/sicp/meta.scm new file mode 100644 index 0000000..94dc784 --- /dev/null +++ b/lore/sicp/meta.scm @@ -0,0 +1,20 @@ +(define (eval exp env) + (cond + ((self-evaluating? exp) exp) + ((variable? exp) (lookup-variable-value exp env)) + ((quoted? exp) (text-of-quotation exp)) + ((assignment? exp) (eval-assignment exp env)) + ((definition? exp) (eval-definition exp env)) + ((if? exp) (eval-if exp env)) + ((lambda? exp) + (make-procedure (lambda-parameters exp) + (lambda-body exp) + env)) + ((begin? exp) + (eval-sequence (begin-actions exp) env)) + ((cond? exp) (eval (cond->if exp) env)) + ((application? exp) + (apply (eval (operator exp) env) + (list-of-values (operands exp) env))) + (else + (error "Unknown expression type -- EVAL" exp)))) -- cgit v1.2.3