From c411f67a2cd2afef1ff81f2fb0824c1ec473517a Mon Sep 17 00:00:00 2001
From: jottbee <jottbee>
Date: Tue, 15 Feb 2005 18:54:47 +0000
Subject: [PATCH] make-is-out-of-date? is more readable now; small improvement
 target-mtime doesn't need to be checked for each prereq.

---
 templates.scm | 40 ++++++++++++++++++++++------------------
 1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/templates.scm b/templates.scm
index da15584..75e615e 100644
--- a/templates.scm
+++ b/templates.scm
@@ -6,7 +6,7 @@
     (let ((cooked-state (last args))
 	  (prereqs-results (cdr (reverse (cdr args)))))
       (cons (begin 
-	      (display ";;; rule      : ")
+	      (display ";;; file      : ")
 	      (display target)
 	      (newline)
 	      (bind-fluids-gnu target prereqs prereqs-results thunk))
@@ -61,18 +61,22 @@
       (cons (file-not-exists? target) init-state))))
 
 (define (make-is-out-of-date? target . prereqs)
-  (lambda args 
+ (lambda args 
 ;    (breakpoint "make-is-out-of-date?")
     (let ((init-state (last args)))
-      (cons (or (file-not-exists? target)
-		(and (not (null? prereqs))
-		     (let for-each-prereq ((prereq (car prereqs))
-					   (todo (cdr prereqs)))
-		       (cond
-			((file-not-exists? prereq) #t)
-			((> (file-last-mod prereq) (file-last-mod target)) #t)
-			((null? todo) #f)
-			(else (for-each-prereq (car todo) (cdr todo)))))))
+      (cons (if (file-not-exists? target)
+		#t
+		(if (null? prereqs)
+		    #f
+		    (let ((target-mtime (file-last-mod target)))
+		      (let for-each-prereq ((prereq (car prereqs))
+					    (todo (cdr prereqs)))
+			(cond
+			 ((file-not-exists? prereq) 
+			  (error "nonexistent prerequisite" prereq))
+			 ((> (file-last-mod prereq) target-mtime) #t)
+			 ((null? todo) #f)
+			 (else (for-each-prereq (car todo) (cdr todo))))))))
 	    init-state))))
 
 (define (make-md5-sum-changed? target . prereqs)
@@ -86,13 +90,13 @@
   (let* ((bname (string-append basename extension))
 	 (file (expand-file-name bname (cwd))))
     (if (file-exists? file)
-	 (let* ((outport (open-input-file file))
-		(strls (port->string-list outport)))
-	   ;; (display ";;; using     : ") (display bname) (newline)
-	   (if (null? strls) 
-	       #f 
-	       (string->number (car strls))))
-	 #f)))
+	(let* ((outport (open-input-file file))
+	       (strls (port->string-list outport)))
+	  ;; (display ";;; using     : ") (display bname) (newline)
+	  (if (null? strls) 
+	      #f 
+	      (string->number (car strls))))
+	#f)))
 
 (define (checksum-into-file basename extension checksum)
   (let* ((bname (string-append basename extension))