Add semi-working bs

1 files changed, 20 insertions, 0 deletions

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))))