use a scheme procedures+eval to manage and transform AST

Removes records for a more-managable scheme-syntax approach. Modules+overriding allows for the IR itself to be represented and evaluated as scheme code during each transformation.

1 files changed, 42 insertions, 0 deletions

diff --git a/src/modules/tacky/traverse.scm b/src/modules/tacky/traverse.scm
new file mode 100644
index 0000000..24c4054
--- /dev/null
+++ b/src/modules/tacky/traverse.scm
@@ -0,0 +1,42 @@
+(define-module (modules tacky traverse)
+  #:use-module (modules ast ir)
+  #:export (prog
+            func
+            stmt
+            unary
+            const))
+
+
+(define (prog srout)
+  (list 'prog srout))
+
+(define (func name instrs)
+  (list 'srout name instrs))
+
+(define (stmt val)
+  (list 'instrs
+        (cons 'list (append (cdr val)
+                            (list (list 'ret (car val)))))))
+
+(define (expr op val)
+  (cond
+   ((integer? val) (make-instruction op (imm val) '()))
+   (#t (make-instruction op (car val) (cdr val)))))
+
+(define (make-instruction op src instrs)
+  (let ((dst (make-temporary)))
+    (cons dst
+            (append instrs
+                    (list (op dst src))))))
+
+(define make-temporary
+  (let ((count 100))
+    (lambda ()
+      (set! count (1+ count))
+      (list 'tmp count))))
+
+(define (neg dst src)
+  (list 'neg dst src))
+
+(define (not dst src)
+  (list 'not dst src))