From 2552a55b8082ebf502cc4dd3b406258ee0977fea Mon Sep 17 00:00:00 2001
From: Dmitry Mikhirev
Date: Thu, 18 Dec 2014 14:55:55 +0300
Subject: expand replacement string just before substitution, after vars set

---
 README.md | 14 ++++++++------
 pcre.c    | 31 ++++++++++++++++++++-----------
 tests.mk  |  6 +++++-
 3 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/README.md b/README.md
index 8b2bcae..77359e2 100644
--- a/README.md
+++ b/README.md
@@ -51,9 +51,9 @@ pattern instead substring as first argument:
     $(pcre_find PATTERN,IN)
     $(m PATTERN,IN)
 
-It searches IN for matching PATTERN. If it occurs, the matched substring is
-returned; otherwise returned string is empty. Note that normally PATTERN is
-not expanded, but IN is expanded before search.
+It searches *IN* for matching *PATTERN*. If it occurs, the matched substring is
+returned; otherwise returned string is empty. Note that normally *PATTERN* is
+not expanded, but *IN* is expanded before search.
 
 ### `pcre_subst` function ###
 
@@ -63,9 +63,11 @@ instead substring as first argument:
     $(pcre_subst PATTERN,REPLACEMENT,TEXT)
     $(s PATTERN,REPLACEMENT,TEXT)
 
-It searches TEXT for matching PATTERN. If it occurs, the matched substring is
-replaced with REPLACEMENT, and the resulting string is returned. If pattern
-does not match, TEXT is returned unchanged.
+It searches *TEXT* for matching *PATTERN*. If it occurs, the matched substring
+is replaced with *REPLACEMENT*, and the resulting string is returned. If pattern
+does not match, *TEXT* is returned unchanged. *PATTERN* is not expanded by default,
+*TEXT* is expanded before search, and *REPLACEMENT* string is expanded just before
+substitution.
 
 Capturing strings
 -----------------
diff --git a/pcre.c b/pcre.c
index ffb9aee..5e932df 100644
--- a/pcre.c
+++ b/pcre.c
@@ -424,6 +424,7 @@ char *subst(const char *name, int argc, char **argv)
 	int erroffset;         /* offset in pattern where error occured */
 	pcre_extra *sd = NULL; /* pattern study data */
 	char *str = NULL;      /* expanded subject string */
+	char *rep = NULL;      /* expanded replacement string */
 	int subjlen;           /* length of subject string */
 	int replen;            /* length of replacement string */
 	int offset = 0;        /* subject string offset */
@@ -471,9 +472,7 @@ char *subst(const char *name, int argc, char **argv)
 
 	/* expand subject string */
 	str = gmk_expand(argv[2]);
-
 	subjlen = strlen(str);
-	replen = strlen(argv[1]);
 
 	do {
 		/* execute regexp */
@@ -484,7 +483,16 @@ char *subst(const char *name, int argc, char **argv)
 			goto end_subst;
 		}
 
-		if (ncap > 0) {
+		if (ncap > 0) { /* match found */
+			/* set make vars to captured substrings */
+			set_vars(str, ovec, ncap);
+			/* set named make vars to captured substrings */
+			set_named_vars(re, str, ovec, ncap);
+
+			/* expand replacement string */
+			rep = gmk_expand(argv[1]);
+			replen = strlen(rep);
+
 			newlen = retlen + (ovec[0] - offset) + replen;
 			s = str_extend(retstr, newlen + 1);
 			if (s == NULL) {
@@ -493,14 +501,15 @@ char *subst(const char *name, int argc, char **argv)
 			retstr = s;
 
 			strncpy(retstr + retlen, str + offset, ovec[0] - offset);
-			strncpy(retstr + retlen + ovec[0] - offset, argv[1], replen + 1);
+			strncpy(retstr + retlen + ovec[0] - offset, rep, replen + 1);
 			retlen += ovec[0] - offset + replen;
 
+			/* free expanded replacement string */
+			gmk_free(rep);
+			rep = NULL;
+
 			/* where to start next search */
 			offset = ovec[1];
-
-			/* set named make vars to captured substrings */
-			set_named_vars(re, str, ovec, ncap);
 		}
 	} while (global && (ncap != PCRE_ERROR_NOMATCH));
 
@@ -524,14 +533,14 @@ end_subst:
 	#endif
 	}
 
-	/* set make vars to captured substrings */
-	set_vars(str, ovec, ncap);
-
 	if (str != NULL) {
 		gmk_free(str);
 	}
-	return retstr;
+	if (rep != NULL) {
+		gmk_free(rep);
+	}
 
+	return retstr;
 }
 
 int pcre_gmk_setup()
diff --git a/tests.mk b/tests.mk
index 10e34c8..3f40808 100644
--- a/tests.mk
+++ b/tests.mk
@@ -2,7 +2,7 @@ ifneq ($(findstring 4.,$(MAKE_VERSION)),4.)
     $(error you need GNU make 4.x to run tests)
 endif
 
-NUMTESTS = 23
+NUMTESTS = 25
 tests := $(foreach num,$(shell seq -f%03g $(NUMTESTS)),test$(num))
 
 load pcre.so
@@ -74,6 +74,10 @@ test021 = "$(s aaa,x,dcbaaa)" = "dcbx"
 test022 = "$(s aaa,x,aaabbaaa,g)" = "xbbx"
 test023 = "$(s a,x,aaa,g)" = "xxx"
 
+# test expansion of substituted string
+test024 = "$(s a(.),$(1),aaabac,g)" = "abc"
+test025 = "$(s (?<var>.)a,$(var),aabaca,g)" = "abc"
+
 ### END OF TEST EXPRESSIONS ###
 
 test%:
-- 
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