regextract_or_else iterate

c/lib/mlrregex.c

@@ -215,6 +215,20 @@ char* regextract(char* input, regex_t* pregex) {
 	return mlr_alloc_string_from_char_range(&input[pmatch->rm_so], len);
 }
 
+// ----------------------------------------------------------------
+char* regextract_or_else(char* input, regex_t* pregex, char* default_value) {
+	const size_t nmatchmax = 1;
+	regmatch_t matches[nmatchmax];
+
+	int matched = regmatch_or_die(pregex, input, nmatchmax, matches);
+	if (!matched) {
+		return mlr_strdup_or_die(default_value);
+	}
+	regmatch_t* pmatch = &matches[0];
+	int len = pmatch->rm_eo - pmatch->rm_so;
+	return mlr_alloc_string_from_char_range(&input[pmatch->rm_so], len);
+}
+
 // ----------------------------------------------------------------
 // Slot 0 is the entire matched input string.
 // Slots 1 and up are substring matches for parenthesized capture expressions (if any).

c/lib/mlrregex.h

@@ -35,6 +35,7 @@ char* regex_gsub(char* input, regex_t* pregex, string_builder_t* psb, char* repl
 
 // The return value is dynamically allocated if there is a match, else it returns null.
 char* regextract(char* input, regex_t* pregex);
+char* regextract_or_else(char* input, regex_t* pregex, char* default_value);
 
 // The regex library gives us an array of match pointers into the input string. This function strdups them
 // out into separate storage, to implement "\0", "\1", "\2", etc. regex-captures for the =~ and !=~ operators.

c/lib/mvfuncs.c

@@ -214,6 +214,26 @@ mv_t regextract_precomp_func(mv_t* pval1, regex_t* pregex) {
 	}
 }
 
+// ----------------------------------------------------------------
+mv_t regextract_or_else_no_precomp_func(mv_t* pval1, mv_t* pval2, mv_t* pval3) {
+	regex_t regex;
+	mv_t rv = regextract_or_else_precomp_func(pval1, regcomp_or_die(&regex, pval2->u.strv, 0), pval3);
+	regfree(&regex);
+	mv_free(pval2);
+	return rv;
+}
+
+// ----------------------------------------------------------------
+mv_t regextract_or_else_precomp_func(mv_t* pval1, regex_t* pregex, mv_t* pval3) {
+	char* input  = pval1->u.strv;
+	char* default_value  = pval3->u.strv;
+	char* output = regextract_or_else(input, pregex, default_value);
+
+	mv_free(pval1);
+	mv_free(pval3);
+	return mv_from_string_with_free(output);
+}
+
 // ----------------------------------------------------------------
 // String-substitution with no regexes or special characters.
 // It is assumed that all inputs have already been checked to be strings.

c/lib/mvfuncs.h

@@ -207,6 +207,8 @@ mv_t gsub_no_precomp_func(mv_t* pval1, mv_t* pval2, mv_t* pval3);
 mv_t gsub_precomp_func(mv_t* pval1, regex_t* pregex, string_builder_t* psb, mv_t* pval3);
 mv_t regextract_no_precomp_func(mv_t* pval1, mv_t* pval2);
 mv_t regextract_precomp_func(mv_t* pval1, regex_t* pregex);
+mv_t regextract_or_else_no_precomp_func(mv_t* pval1, mv_t* pval2, mv_t* pval3);
+mv_t regextract_or_else_precomp_func(mv_t* pval1, regex_t* pregex, mv_t* pval3);
 // String-substitution with no regexes or special characters.
 mv_t s_sss_ssub_func(mv_t* pstring, mv_t* pold, mv_t* pnew);