From: Chris Hanson <org/chris-hanson/cph>
Date: Tue, 16 Sep 2008 20:03:47 +0000 (+0000)
Subject: Add post-pass to suppress "unreferenced variable" errors in output.
X-Git-Tag: 20090517-FFI~144
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=4e98ef144dd24e4bc4614a48bdeaa40135a4178c;p=mit-scheme.git

Add post-pass to suppress "unreferenced variable" errors in output.
---

diff --git a/v7/src/runtime/structure-parser.scm b/v7/src/runtime/structure-parser.scm
index b47a79fcf..0997c73c8 100644
--- a/v7/src/runtime/structure-parser.scm
+++ b/v7/src/runtime/structure-parser.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Id: structure-parser.scm,v 14.5 2008/09/16 05:50:03 cph Exp $
+$Id: structure-parser.scm,v 14.6 2008/09/16 20:03:47 cph Exp $
 
 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
     1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
@@ -790,9 +790,10 @@ USA.
 ;;; copy expressions.
 
 (define (optimize-result expr)
-  (if enable-optimizer?
-      (peephole-optimizer (optimize-lets expr))
-      expr))
+  (fixup-lambdas
+   (if enable-optimizer?
+       (peephole-optimizer (optimize-lets expr))
+       expr)))
 
 (define enable-optimizer? #t)
 
@@ -876,6 +877,22 @@ USA.
 	     rewrite-lambda
 	     rewrite-loop
 	     rewrite-combination))
+
+(define (fixup-lambdas expr)
+  (walk-expr expr
+	     rewrite-constant
+	     rewrite-quote
+	     rewrite-reference
+	     (lambda (expr loop)
+	       (let ((names (cadr expr))
+		     (body (loop (caddr expr))))
+		 `(LAMBDA ,names
+		    ,@(filter (lambda (name)
+				(= (count-refs-in name body) 0))
+			      names)
+		    ,body)))
+	     rewrite-loop
+	     rewrite-combination))
 
 (define (peephole-optimizer expr)
   (walk-expr expr