X-Git-Url: http://git.lukelau.me/?p=scheme.git;a=blobdiff_plain;f=codegen.scm;h=70a8ca4aa0df75518989d386502765e90e535137;hp=d30adc54e61a144097c3b0bb541a5835af8c028a;hb=21a9f0aaa56d6dd767cefb30c606f4c62eecff48;hpb=e51b9e423665428c41cddac0642d1e34b18ca1da

diff --git a/codegen.scm b/codegen.scm
index d30adc5..70a8ca4 100644
--- a/codegen.scm
+++ b/codegen.scm
@@ -51,12 +51,17 @@
 	 (inner-si (- si (* (length bindings) wordsize)))
 	 (names (map car bindings))
 	 (exprs (map cadr bindings))
-	 (inner-env (append (map cons names stack-offsets) env)))
-  (for-each (lambda (expr offset)
+
+	 ; recursive let bindings: build environment as we go
+	 (inner-env (fold-left
+		     (lambda (env name expr offset)
 		       (codegen-expr expr inner-si env)
-	      (emit "movq %rax, ~a(%rsp)" offset))
-	    exprs stack-offsets)
-  (for-each (lambda (form) (codegen-expr form inner-si inner-env)) body)))
+		       (emit "movq %rax, ~a(%rsp)" offset)
+		       (cons (cons name offset) env))
+		     env names exprs stack-offsets)))
+    (for-each (lambda (form)
+		(codegen-expr form inner-si inner-env))
+	      body)))
 
 (define (codegen-var name si env)
   (when (not (assoc name env))
@@ -131,10 +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))
@@ -144,29 +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))))
@@ -176,9 +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 '())
@@ -191,17 +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")
@@ -243,8 +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))