From: Guillermo J. Rozas <edu/mit/csail/zurich/gjr>
Date: Fri, 21 Aug 1987 02:21:17 +0000 (+0000)
Subject: Fix order of argument evaluation bug in make-instruction-parser.
X-Git-Tag: 20090517-FFI~13128
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=ae402153f78a738be19d1a8526199b2eb039042f;p=mit-scheme.git

Fix order of argument evaluation bug in make-instruction-parser.
---

diff --git a/v7/src/compiler/machines/vax/dsyn.scm b/v7/src/compiler/machines/vax/dsyn.scm
index 3189d6e59..8c8f32563 100644
--- a/v7/src/compiler/machines/vax/dsyn.scm
+++ b/v7/src/compiler/machines/vax/dsyn.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/machines/vax/dsyn.scm,v 1.3 1987/08/20 19:13:58 jinx Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/machines/vax/dsyn.scm,v 1.4 1987/08/21 02:21:17 jinx Exp $
 
 Copyright (c) 1987 Massachusetts Institute of Technology
 
@@ -85,10 +85,21 @@ MIT in each case. |#
 (define (make-instruction-parser prefix operands)
   `(lambda ()
      (append ',prefix
-	     (list ,@(map process-operand operands)))))
-
-(define (process-operand operand)
-  (case (car operand)
-    ((OPERAND) `(decode-operand ',(cadr operand)))
-    ((DISPLACEMENT) `(decode-displacement ,(caadr operand)))
-    (else (error "process-operand: Unknown operand kind" operand))))
+	     (process-operands operands))))
+
+;; A let* is used below to force the order of evaluation.
+
+(define (process-operands operands)
+  (if (null? operands)
+      ''()
+      `(let* ((this ,(let ((operand (car operands)))
+		       (case (car operand)
+			 ((OPERAND)
+			  `(decode-operand ',(cadr operand)))
+			 ((DISPLACEMENT)
+			  `(decode-displacement ,(caadr operand)))
+			 (else
+			  (error "process-operand: Unknown operand kind"
+				 operand)))))
+	      (rest ,(process-operands (cdr operands))))
+	 (cons this rest))))
\ No newline at end of file