Refactor ast "pattern matching" to a single function

[scheme.git] / codegen.scm

diff --git a/codegen.scm b/codegen.scm
index e1b51a60a5ac6c9fcde9f23dd4ca58e9c02f2274..70a8ca4aa0df75518989d386502765e90e535137 100644 (file)
--- a/codegen.scm
+++ b/codegen.scm
@@ -136,10 +136,10 @@
        ))))                    ; move args and capture vars to stack
 
 (define (codegen-expr e si env)
-  (cond ((builtin? e) e)
-       ((closure? e) e)
-       
-       ((app? e)
+  (case (ast-type e)
+    ('builtin e)
+    ('closure e)
+    ('app
      (let ((callee (codegen-expr (car e) si env)))
        (case callee
         ('+ (codegen-add (cdr e) si env))
@@ -149,29 +149,34 @@
         ('bool->int (codegen-expr (cadr e) si env))
         (else (codegen-call callee (cdr e) si env)))))
 
-       ((let? e) (codegen-let
-                  (let-bindings e)
+    ('let (codegen-let (let-bindings e)
                       (let-body e)
                       si
                       env))
-       ((var? e) (codegen-var e si env))
-       ((boolean? e) (emit "movq $~a, %rax" (if e 1 0)))
-       (else (emit "movq $~a, %rax" e))))
+
+    ('var (codegen-var e si env))
+
+    ('string-literal (emit "movq ~a, %rax" label))
+    ('bool-literal (emit "movq $~a, %rax" (if e 1 0)))
+    ('int-literal (emit "movq $~a, %rax" e))
+
+    (else (error #f "don't know how to codegen this"))))
+
 
 (define (fold-map f x) (fold-left append '() (map f x)))
 
 (define (free-vars prog)
   (define bound '())
   (define (collect e)
-    (cond
-     ((builtin? e) '()) ; do nothing
-     ((var? e) (if (memq e bound) '() (list e)))
-     ((lambda? e)
+    (case (ast-type e)
+      ('builtin '()) ; do nothing
+      ('var (if (memq e bound) '() (list e)))
+      ('lambda
          (set! bound (append (lambda-args e) bound))
        (collect (lambda-body e)))
 
-     ((app? e) (fold-map collect e))
-     ((let? e)
+      ('app (fold-map collect e))
+      ('let
          (let ((bind-fvs (fold-map (lambda (a)
                                      ((set! bound (cons (car a) bound))
                                       (collect (cdr a))))
@@ -181,9 +186,6 @@
       (else '())))
   (collect prog))
 
-(define (closure? e)
-  (and (list? e) (eqv? (car e) 'closure)))
-
                                        ; ((lambda (x) (+ x 1)) 42) => {lambda0: (x) (+ x 1)}, (@lambda0 42)
 (define (extract-lambdas program)
   (define lambdas '())
@@ -196,17 +198,19 @@
       (set! lambdas (cons new-lambda lambdas))
       `(closure ,label ,captured))) ; todo: should we string->symbol?
   (define (extract e)
-    (cond
-     ((lambda? e) (add-lambda e))
-     ((let? e) `(let
+    (case (ast-type e)
+     ('lambda (add-lambda e))
+     ('let `(let
                    ,(map extract (let-bindings e))
                  ,@(map extract (let-body e))))
-     ((app? e) (append (list (extract (car e)))
+     ('app (append (list (extract (car e)))
                       (map extract (cdr e))))
      (else e)))
   (let ((transformed (extract program)))
     (cons lambdas transformed)))
 
+;(define (extract-strings program))
+
 (define (amd64-abi f)
                                        ; preserve registers
   (emit "push %rbp")
@@ -248,8 +252,6 @@
     (else (error #f "need to test out the below"))
     (else (format "~a(%rsp)" (- n 6)))))
 
-                
-
 (define (codegen program)
   (let* ((extract-result (extract-lambdas program))
         (lambdas (car extract-result))