problem set 3 files

1 files changed, 48 insertions, 0 deletions

diff --git a/ps03_evalapply/repl.scm b/ps03_evalapply/repl.scm
new file mode 100644
index 0000000..94a0500
--- /dev/null
+++ b/ps03_evalapply/repl.scm
@@ -0,0 +1,48 @@
+(declare (usual-integrations write write-line pp eval))
+
+(define write
+  (make-generic-operator 1
+    (access write user-initial-environment)))
+
+(define write-line
+  (make-generic-operator 1
+    (access write-line user-initial-environment)))
+
+(define pp
+  (make-generic-operator 1
+    (access pp user-initial-environment)))
+
+(define (procedure-printable-representation procedure)
+  `(compound-procedure
+    ,(procedure-parameters procedure)
+    ,(procedure-body procedure)
+    <procedure-environment>))
+
+(defhandler write
+  (compose write procedure-printable-representation)
+  compound-procedure?)
+
+(defhandler write-line
+  (compose write-line procedure-printable-representation)
+  compound-procedure?)
+
+(defhandler pp
+  (compose pp procedure-printable-representation)
+  compound-procedure?)
+
+
+ (define (read) (prompt-for-command-expression "eval> "))
+
+(define the-global-environment)
+
+(define (init)
+  (set! the-global-environment
+	(extend-environment '() '() the-empty-environment))
+  (repl))
+
+(define (repl)
+  (let ((input (read)))
+    (write-line (eval input the-global-environment))
+    (repl)))
+
+(define go repl)