Var_Subst is actually two distinct functions folded into one:

split the function specific to for.c out, and give them more sensible
arguments at the same time.

This makes .for loop handling more efficient, as we have some heuristic
to evaluate the size of the buffer needed...

9 files changed, 180 insertions, 162 deletions

diff --git a/usr.bin/make/arch.c b/usr.bin/make/arch.c
index 7504147f54e..21fa1851635 100644
--- a/usr.bin/make/arch.c
+++ b/usr.bin/make/arch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: arch.c,v 1.17 1999/12/06 22:28:43 espie Exp $	*/
+/*	$OpenBSD: arch.c,v 1.18 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: arch.c,v 1.17 1996/11/06 17:58:59 christos Exp $	*/
 
 /*
@@ -43,7 +43,7 @@
 #if 0
 static char sccsid[] = "@(#)arch.c	8.2 (Berkeley) 1/2/94";
 #else
-static char rcsid[] = "$OpenBSD: arch.c,v 1.17 1999/12/06 22:28:43 espie Exp $";
+static char rcsid[] = "$OpenBSD: arch.c,v 1.18 1999/12/16 17:27:18 espie Exp $";
 #endif
 #endif /* not lint */
 
@@ -241,7 +241,7 @@ Arch_ParseArchive (linePtr, nodeLst, ctxt)
 
     *cp++ = '\0';
     if (subLibName) {
-	libName = Var_Subst(NULL, libName, ctxt, TRUE);
+	libName = Var_Subst(libName, ctxt, TRUE);
     }
 
 
@@ -320,7 +320,7 @@ Arch_ParseArchive (linePtr, nodeLst, ctxt)
 	    char    *sacrifice;
 	    char    *oldMemName = memName;
 
-	    memName = Var_Subst(NULL, memName, ctxt, TRUE);
+	    memName = Var_Subst(memName, ctxt, TRUE);
 
 	    /*
 	     * Now form an archive spec and recurse to deal with nested
diff --git a/usr.bin/make/compat.c b/usr.bin/make/compat.c
index 299cefe3e57..162549c8940 100644
--- a/usr.bin/make/compat.c
+++ b/usr.bin/make/compat.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: compat.c,v 1.15 1999/12/06 22:28:44 espie Exp $	*/
+/*	$OpenBSD: compat.c,v 1.16 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: compat.c,v 1.14 1996/11/06 17:59:01 christos Exp $	*/
 
 /*
@@ -43,7 +43,7 @@
 #if 0
 static char sccsid[] = "@(#)compat.c	8.2 (Berkeley) 3/19/94";
 #else
-static char rcsid[] = "$OpenBSD: compat.c,v 1.15 1999/12/06 22:28:44 espie Exp $";
+static char rcsid[] = "$OpenBSD: compat.c,v 1.16 1999/12/16 17:27:18 espie Exp $";
 #endif
 #endif /* not lint */
 
@@ -234,7 +234,7 @@ CompatRunCommand (cmdp, gnp)
     errCheck = !(gn->type & OP_IGNORE);
 
     cmdNode = Lst_Member (gn->commands, (ClientData)cmd);
-    cmdStart = Var_Subst (NULL, cmd, gn, FALSE);
+    cmdStart = Var_Subst(cmd, gn, FALSE);
 
     /*
      * brk_string will return an argv with a NULL in av[0], thus causing
diff --git a/usr.bin/make/extern.h b/usr.bin/make/extern.h
index fb090ac4dc4..264bf01db84 100644
--- a/usr.bin/make/extern.h
+++ b/usr.bin/make/extern.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: extern.h,v 1.16 1999/12/16 17:07:20 espie Exp $	*/
+/*	$OpenBSD: extern.h,v 1.17 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: nonints.h,v 1.12 1996/11/06 17:59:19 christos Exp $	*/
 
 /*-
@@ -147,7 +147,8 @@ void Var_Append __P((char *, char *, GNode *));
 Boolean Var_Exists __P((char *, GNode *));
 char *Var_Value __P((char *, GNode *));
 char *Var_Parse __P((char *, GNode *, Boolean, int *, Boolean *));
-char *Var_Subst __P((char *, char *, GNode *, Boolean));
+char *Var_Subst __P((char *, GNode *, Boolean));
+void Var_SubstVar __P((Buffer, char *, const char *, GNode *));
 char *Var_GetTail __P((char *));
 char *Var_GetHead __P((char *));
 void Var_Init __P((void));
diff --git a/usr.bin/make/for.c b/usr.bin/make/for.c
index 751038df5c0..ba4f89459f5 100644
--- a/usr.bin/make/for.c
+++ b/usr.bin/make/for.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: for.c,v 1.12 1999/12/16 17:24:11 espie Exp $	*/
+/*	$OpenBSD: for.c,v 1.13 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: for.c,v 1.4 1996/11/06 17:59:05 christos Exp $	*/
 
 /*
@@ -82,7 +82,7 @@
 #if 0
 static char sccsid[] = "@(#)for.c	8.1 (Berkeley) 6/6/93";
 #else
-static char rcsid[] = "$OpenBSD: for.c,v 1.12 1999/12/16 17:24:11 espie Exp $";
+static char rcsid[] = "$OpenBSD: for.c,v 1.13 1999/12/16 17:27:18 espie Exp $";
 #endif
 #endif /* not lint */
 
@@ -105,6 +105,7 @@ struct For_ {
     char		*text;		/* unexpanded text       	*/
     char		*var;		/* Index name		 	*/
     Lst  		lst;		/* List of items	 	*/
+    size_t		guess;		/* Estimated expansion size	*/
     BUFFER		buf;		/* Accumulating text	 	*/
     unsigned long	lineno;		/* Line number at start of loop */
     unsigned long	level;		/* Nesting level		*/
@@ -197,7 +198,7 @@ For_Eval(line)
     arg->var = interval_dup(wrd, endVar);
 
     /* Make a list with the remaining words.  */
-    sub = Var_Subst(NULL, ptr, VAR_GLOBAL, FALSE);
+    sub = Var_Subst(ptr, VAR_GLOBAL, FALSE);
     if (DEBUG(FOR))
 	(void)fprintf(stderr, "For: Iterator %s List %s\n", arg->var, sub);
 
@@ -260,6 +261,7 @@ For_Accumulate(arg, line)
 }
 
 
+#define GUESS_EXPANSION 32
 /*-
  *-----------------------------------------------------------------------
  * ForExec --
@@ -274,11 +276,15 @@ ForExec(namep, argp)
     char *name = (char *)namep;
     For *arg = (For *)argp;
 
+    Buf_Init(&arg->buf, arg->guess);
     Var_Set(arg->var, name, VAR_GLOBAL);
     if (DEBUG(FOR))
 	(void)fprintf(stderr, "--- %s = %s\n", arg->var, name);
-    Parse_FromString(Var_Subst(arg->var, arg->text, VAR_GLOBAL, FALSE), 
-    	arg->lineno);
+    Var_SubstVar(&arg->buf, arg->text, arg->var, VAR_GLOBAL);
+    if (Buf_Size(&arg->buf) >= arg->guess)
+    	arg->guess = Buf_Size(&arg->buf) + GUESS_EXPANSION;
+    
+    Parse_FromString(Buf_Retrieve(&arg->buf), arg->lineno);
     Var_Delete(arg->var, VAR_GLOBAL);
     return 0;
 }
@@ -296,6 +302,7 @@ For_Run(arg)
     For *arg;
 {
     arg->text = Buf_Retrieve(&arg->buf);
+    arg->guess = Buf_Size(&arg->buf) + GUESS_EXPANSION;
 
     Lst_ForEach(arg->lst, ForExec, (ClientData)arg);
     free(arg->var);
diff --git a/usr.bin/make/job.c b/usr.bin/make/job.c
index 715cb9a85ce..16fa9528dd1 100644
--- a/usr.bin/make/job.c
+++ b/usr.bin/make/job.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: job.c,v 1.15 1999/12/06 22:28:44 espie Exp $	*/
+/*	$OpenBSD: job.c,v 1.16 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: job.c,v 1.16 1996/11/06 17:59:08 christos Exp $	*/
 
 /*
@@ -43,7 +43,7 @@
 #if 0
 static char sccsid[] = "@(#)job.c	8.2 (Berkeley) 3/19/94";
 #else
-static char rcsid[] = "$OpenBSD: job.c,v 1.15 1999/12/06 22:28:44 espie Exp $";
+static char rcsid[] = "$OpenBSD: job.c,v 1.16 1999/12/16 17:27:18 espie Exp $";
 #endif
 #endif /* not lint */
 
@@ -558,7 +558,7 @@ JobPrintCommand(cmdp, jobp)
      * the variables in the command.
      */
     cmdNode = Lst_Member(job->node->commands, (ClientData)cmd);
-    cmdStart = cmd = Var_Subst(NULL, cmd, job->node, FALSE);
+    cmdStart = cmd = Var_Subst(cmd, job->node, FALSE);
     Lst_Replace(cmdNode, (ClientData)cmdStart);
 
     cmdTemplate = "%s\n";
@@ -678,7 +678,7 @@ JobSaveCommand(cmd, gn)
     ClientData   cmd;
     ClientData   gn;
 {
-    cmd = (ClientData) Var_Subst(NULL, (char *) cmd, (GNode *) gn, FALSE);
+    cmd = (ClientData) Var_Subst((char *) cmd, (GNode *) gn, FALSE);
     (void) Lst_AtEnd(postCommands->commands, cmd);
     return(0);
 }
diff --git a/usr.bin/make/main.c b/usr.bin/make/main.c
index a9da5cc828d..2453d71e9a4 100644
--- a/usr.bin/make/main.c
+++ b/usr.bin/make/main.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: main.c,v 1.22 1999/12/16 17:02:45 espie Exp $	*/
+/*	$OpenBSD: main.c,v 1.23 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: main.c,v 1.34 1997/03/24 20:56:36 gwr Exp $	*/
 
 /*
@@ -49,7 +49,7 @@ static char copyright[] =
 #if 0
 static char sccsid[] = "@(#)main.c	8.3 (Berkeley) 3/19/94";
 #else
-static char rcsid[] = "$OpenBSD: main.c,v 1.22 1999/12/16 17:02:45 espie Exp $";
+static char rcsid[] = "$OpenBSD: main.c,v 1.23 1999/12/16 17:27:18 espie Exp $";
 #endif
 #endif /* not lint */
 
@@ -755,7 +755,7 @@ main(argc, argv)
 		 */
 		static char VPATH[] = "${VPATH}";
 
-		vpath = Var_Subst(NULL, VPATH, VAR_CMD, FALSE);
+		vpath = Var_Subst(VPATH, VAR_CMD, FALSE);
 		path = vpath;
 		do {
 			/* skip to end of directory */
diff --git a/usr.bin/make/parse.c b/usr.bin/make/parse.c
index 9de8d51c818..1eb4d4e51fa 100644
--- a/usr.bin/make/parse.c
+++ b/usr.bin/make/parse.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.c,v 1.30 1999/12/16 17:07:21 espie Exp $	*/
+/*	$OpenBSD: parse.c,v 1.31 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: parse.c,v 1.29 1997/03/10 21:20:04 christos Exp $	*/
 
 /*
@@ -43,7 +43,7 @@
 #if 0
 static char sccsid[] = "@(#)parse.c	8.3 (Berkeley) 3/19/94";
 #else
-static char rcsid[] = "$OpenBSD: parse.c,v 1.30 1999/12/16 17:07:21 espie Exp $";
+static char rcsid[] = "$OpenBSD: parse.c,v 1.31 1999/12/16 17:27:18 espie Exp $";
 #endif
 #endif /* not lint */
 
@@ -1535,7 +1535,7 @@ Parse_DoVar (line, ctxt)
 	Boolean	  oldOldVars = oldVars;
 
 	oldVars = FALSE;
-	cp = Var_Subst(NULL, cp, ctxt, FALSE);
+	cp = Var_Subst(cp, ctxt, FALSE);
 	oldVars = oldOldVars;
 
 	Var_Set(line, cp, ctxt);
@@ -1551,7 +1551,7 @@ Parse_DoVar (line, ctxt)
 	     * expansion on the whole thing. The resulting string will need
 	     * freeing when we're done, so set freeCmd to TRUE.
 	     */
-	    cp = Var_Subst(NULL, cp, VAR_CMD, TRUE);
+	    cp = Var_Subst(cp, VAR_CMD, TRUE);
 	    freeCmd = TRUE;
 	}
 
@@ -1715,7 +1715,7 @@ ParseDoInclude (file)
      * Substitute for any variables in the file name before trying to
      * find the thing.
      */
-    file = Var_Subst (NULL, file, VAR_CMD, FALSE);
+    file = Var_Subst(file, VAR_CMD, FALSE);
 
     /*
      * Now we know the file's name and its search path, we attempt to
@@ -1915,7 +1915,7 @@ ParseTraditionalInclude (file)
      * Substitute for any variables in the file name before trying to
      * find the thing.
      */
-    file = Var_Subst (NULL, file, VAR_CMD, FALSE);
+    file = Var_Subst(file, VAR_CMD, FALSE);
 
     /*
      * Now we know the file's name, we attempt to find the durn thing.
@@ -2586,7 +2586,7 @@ Parse_File(name, stream)
 #endif
 		    ParseFinishLine();
 
-		    cp = Var_Subst (NULL, line, VAR_CMD, TRUE);
+		    cp = Var_Subst(line, VAR_CMD, TRUE);
 		    free (line);
 		    line = cp;
 
diff --git a/usr.bin/make/suff.c b/usr.bin/make/suff.c
index c2a070833e5..47572593286 100644
--- a/usr.bin/make/suff.c
+++ b/usr.bin/make/suff.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: suff.c,v 1.15 1999/12/06 22:28:44 espie Exp $	*/
+/*	$OpenBSD: suff.c,v 1.16 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: suff.c,v 1.13 1996/11/06 17:59:25 christos Exp $	*/
 
 /*
@@ -43,7 +43,7 @@
 #if 0
 static char sccsid[] = "@(#)suff.c	8.4 (Berkeley) 3/21/94";
 #else
-static char rcsid[] = "$OpenBSD: suff.c,v 1.15 1999/12/06 22:28:44 espie Exp $";
+static char rcsid[] = "$OpenBSD: suff.c,v 1.16 1999/12/16 17:27:18 espie Exp $";
 #endif
 #endif /* not lint */
 
@@ -1359,7 +1359,7 @@ SuffExpandChildren(cgnp, pgnp)
 	if (DEBUG(SUFF)) {
 	    printf("Expanding \"%s\"...", cgn->name);
 	}
-	cp = Var_Subst(NULL, cgn->name, pgn, TRUE);
+	cp = Var_Subst(cgn->name, pgn, TRUE);
 
 	if (cp != (char *)NULL) {
 	    Lst	    members = Lst_Init(FALSE);
diff --git a/usr.bin/make/var.c b/usr.bin/make/var.c
index 7e94c74872f..db25dde3544 100644
--- a/usr.bin/make/var.c
+++ b/usr.bin/make/var.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: var.c,v 1.23 1999/12/16 17:02:45 espie Exp $	*/
+/*	$OpenBSD: var.c,v 1.24 1999/12/16 17:27:18 espie Exp $	*/
 /*	$NetBSD: var.c,v 1.18 1997/03/18 19:24:46 christos Exp $	*/
 
 /*
@@ -70,7 +70,7 @@
 #if 0
 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 3/19/94";
 #else
-static char rcsid[] = "$OpenBSD: var.c,v 1.23 1999/12/16 17:02:45 espie Exp $";
+static char rcsid[] = "$OpenBSD: var.c,v 1.24 1999/12/16 17:27:18 espie Exp $";
 #endif
 #endif /* not lint */
 
@@ -1672,7 +1672,7 @@ Var_Parse (str, ctxt, err, lengthPtr, freePtr)
      */
     str = VarValue(v);
     if (strchr (str, '$') != (char *)NULL) {
-	str = Var_Subst(NULL, str, ctxt, err);
+	str = Var_Subst(str, ctxt, err);
 	*freePtr = TRUE;
     }
 
@@ -2091,7 +2091,7 @@ cleanup:
 /*-
  *-----------------------------------------------------------------------
  * Var_Subst  --
- *	Substitute for all variables in the given string in the given context
+ *	Substitute for all variables in a string in a context
  *	If undefErr is TRUE, Parse_Error will be called when an undefined
  *	variable is encountered.
  *
@@ -2103,16 +2103,12 @@ cleanup:
  *-----------------------------------------------------------------------
  */
 char *
-Var_Subst (var, str, ctxt, undefErr)
-    char	  *var;		    /* Named variable || NULL for all */
+Var_Subst(str, ctxt, undefErr)
     char 	  *str;	    	    /* the string in which to substitute */
     GNode         *ctxt;	    /* the context wherein to find variables */
     Boolean 	  undefErr; 	    /* TRUE if undefineds are an error */
 {
-    BUFFER  	  buf;	    	    /* Buffer for forming things */
-    char    	  *val;		    /* Value to substitute for a variable */
-    int	    	  length;   	    /* Length of the variable invocation */
-    Boolean 	  doFree;   	    /* Set true if val should be freed */
+    BUFFER 	  buf;	    	    /* Buffer for forming things */
     static Boolean errorReported;   /* Set true if an error has already
 				     * been reported to prevent a plethora
 				     * of messages when recursing */
@@ -2120,134 +2116,148 @@ Var_Subst (var, str, ctxt, undefErr)
     Buf_Init(&buf, MAKE_BSIZE);
     errorReported = FALSE;
 
-    while (*str) {
-	if (var == NULL && (*str == '$') && (str[1] == '$')) {
-	    /*
-	     * A dollar sign may be escaped either with another dollar sign.
-	     * In such a case, we skip over the escape character and store the
-	     * dollar sign into the buffer directly.
-	     */
-	    str++;
-	    Buf_AddChar(&buf, *str);
-	    str++;
-	} else if (*str != '$') {
-	    /*
-	     * Skip as many characters as possible -- either to the end of
-	     * the string or to the next dollar sign (variable invocation).
-	     */
-	    char  *cp;
+    for (;;) {
+	char		*val;		/* Value to substitute for a variable */
+	size_t		length;		/* Length of the variable invocation */
+	Boolean		doFree;		/* Set true if val should be freed */
+	const char *cp;
+
+	/* copy uninteresting stuff */
+	for (cp = str; *str != '\0' && *str != '$'; str++)
+	    ;
+	Buf_AddInterval(&buf, cp, str);
+	if (*str == '\0')
+	    break;
+	if (str[1] == '$') {
+	    /* A dollar sign may be escaped with another dollar sign.  */
+	    Buf_AddChar(&buf, '$');
+	    str += 2;
+	    continue;
+	}
+	val = Var_Parse(str, ctxt, undefErr, &length, &doFree);
+	/* When we come down here, val should either point to the
+	 * value of this variable, suitably modified, or be NULL.
+	 * Length should be the total length of the potential
+	 * variable invocation (from $ to end character...) */
+	if (val == var_Error || val == varNoError) {
+	    /* If performing old-time variable substitution, skip over
+	     * the variable and continue with the substitution. Otherwise,
+	     * store the dollar sign and advance str so we continue with
+	     * the string...  */
+	    if (oldVars) {
+		str += length;
+	    } else if (undefErr) {
+		/* If variable is undefined, complain and skip the
+		 * variable. The complaint will stop us from doing anything
+		 * when the file is parsed.  */
+		if (!errorReported) {
+		    Parse_Error(PARSE_FATAL,
+				 "Undefined variable \"%.*s\"",length,str);
+		}
+		str += length;
+		errorReported = TRUE;
+	    } else {
+		Buf_AddChar(&buf, *str);
+		str += 1;
+	    }
+	} else {
+	    /* We've now got a variable structure to store in. But first,
+	     * advance the string pointer.  */
+	    str += length;
+
+	    /* Copy all the characters from the variable value straight
+	     * into the new string.  */
+	    Buf_AddString(&buf, val);
+	    if (doFree)
+		free(val);
+	}
+    }
+    return  Buf_Retrieve(&buf);
+}
 
-	    for (cp = str++; *str != '$' && *str != '\0'; str++)
+/*-
+ *-----------------------------------------------------------------------
+ * Var_SubstVar  --
+ *	Substitute for one variable in the given string in the given context
+ *	If undefErr is TRUE, Parse_Error will be called when an undefined
+ *	variable is encountered.
+ *
+ * Side Effects:
+ *	Append the result to the buffer
+ *-----------------------------------------------------------------------
+ */
+void
+Var_SubstVar(buf, str, var, ctxt)
+    Buffer	buf;		/* Where to store the result */
+    char	*str;	        /* The string in which to substitute */
+    const char	*var;		/* Named variable */
+    GNode	*ctxt;		/* The context wherein to find variables */
+{
+    char	*val;		/* Value substituted for a variable */
+    size_t	length;		/* Length of the variable invocation */
+    Boolean	doFree;		/* Set true if val should be freed */
+
+    for (;;) {
+	const char *cp;
+	/* copy uninteresting stuff */
+	for (cp = str; *str != '\0' && *str != '$'; str++)
+	    ;
+	Buf_AddInterval(buf, cp, str);
+	if (*str == '\0')
+	    break;
+	if (str[1] == '$') {
+	    Buf_AddString(buf, "$$");
+	    str += 2;
+	    continue;
+	}
+	if (str[1] != '(' && str[1] != '{') {
+	    if (str[1] != *var || var[1] != '\0') {
+		Buf_AddChars(buf, 2, str);
+		str += 2;
 		continue;
-	    Buf_AddInterval(&buf, cp, str);
+	    }
 	} else {
-	    if (var != NULL) {
-		int expand;
-		for (;;) {
-		    if (str[1] != '(' && str[1] != '{') {
-			if (str[1] != *var || var[1] != '\0') {
-			    Buf_AddChars(&buf, 2, str);
-			    str += 2;
-			    expand = FALSE;
-			}
-			else
-			    expand = TRUE;
-			break;
-		    }
-		    else {
-			char *p;
-
-			/*
-			 * Scan up to the end of the variable name.
-			 */
-			for (p = &str[2]; *p &&
-			     *p != ':' && *p != ')' && *p != '}'; p++)
-			    if (*p == '$')
-				break;
-			/*
-			 * A variable inside the variable. We cannot expand
-			 * the external variable yet, so we try again with
-			 * the nested one
-			 */
-			if (*p == '$') {
-			    Buf_AddInterval(&buf, str, p);
-			    str = p;
-			    continue;
-			}
-
-			if (strncmp(var, str + 2, p - str - 2) != 0 ||
-			    var[p - str - 2] != '\0') {
-			    /*
-			     * Not the variable we want to expand, scan
-			     * until the next variable
-			     */
-			    for (;*p != '$' && *p != '\0'; p++)
-				continue;
-			    Buf_AddInterval(&buf, str, p);
-			    str = p;
-			    expand = FALSE;
-			}
-			else
-			    expand = TRUE;
-			break;
-		    }
-		}
-		if (!expand)
-		    continue;
+	    char *p;
+	    char endc;
+
+	    if (str[1] == '(')
+		endc = ')';
+	    else if (str[1] == '{')
+		endc = '}';
+
+	    /* Find the end of the variable specification.  */
+	    p = str+2;
+	    while (*p != '\0' && *p != ':' && *p != endc && *p != '$')
+		p++;
+	    /* A variable inside the variable.  We don't know how to
+	     * expand the external variable at this point, so we try 
+	     * again with the nested variable.  */
+	    if (*p == '$') {
+		Buf_AddInterval(buf, str, p);
+		str = p;
+		continue;
 	    }
 
-	    val = Var_Parse (str, ctxt, undefErr, &length, &doFree);
-
-	    /*
-	     * When we come down here, val should either point to the
-	     * value of this variable, suitably modified, or be NULL.
-	     * Length should be the total length of the potential
-	     * variable invocation (from $ to end character...)
-	     */
-	    if (val == var_Error || val == varNoError) {
-		/*
-		 * If performing old-time variable substitution, skip over
-		 * the variable and continue with the substitution. Otherwise,
-		 * store the dollar sign and advance str so we continue with
-		 * the string...
-		 */
-		if (oldVars) {
-		    str += length;
-		} else if (undefErr) {
-		    /*
-		     * If variable is undefined, complain and skip the
-		     * variable. The complaint will stop us from doing anything
-		     * when the file is parsed.
-		     */
-		    if (!errorReported) {
-			Parse_Error (PARSE_FATAL,
-				     "Undefined variable \"%.*s\"",length,str);
-		    }
-		    str += length;
-		    errorReported = TRUE;
-		} else {
-		    Buf_AddChar(&buf, *str);
-		    str += 1;
-		}
-	    } else {
-		/*
-		 * We've now got a variable structure to store in. But first,
-		 * advance the string pointer.
-		 */
-		str += length;
-
-		/*
-		 * Copy all the characters from the variable value straight
-		 * into the new string.
-		 */
-		Buf_AddString(&buf, val);
-		if (doFree)
-		    free(val);
-	    }
+	    if (strncmp(var, str + 2, p - str - 2) != 0 ||
+		var[p - str - 2] != '\0') {
+		/* Not the variable we want to expand.  */
+		Buf_AddInterval(buf, str, p);
+		str = p;
+		continue;
+	    } 
 	}
+	/* okay, so we've found the variable we want to expand.  */
+	val = Var_Parse(str, ctxt, FALSE, &length, &doFree);
+	/* We've now got a variable structure to store in. But first,
+	 * advance the string pointer.  */
+	str += length;
+
+	/* Copy all the characters from the variable value straight
+	 * into the new string.  */
+	Buf_AddString(buf, val);
+	if (doFree)
+	    free(val);
     }
-
-    return Buf_Retrieve(&buf);
 }
 
 /*-