Add the set.which() method.

README.rst

@@ -975,6 +975,15 @@ Example::
               + " patterns from the set");
   }
 
+.. _func_set.which:
+
+set.which
+---------
+
+::
+
+	INT set.which(ENUM {FIRST,LAST} select=0)
+
 .. _func_set.string:
 
 set.string

src/tests/set_retrieve.vtc

 # looks like -*- vcl -*-
 
-varnishtest "set .string() and .backend() methods"
+varnishtest "set .which(), .string() and .backend() methods"
 
 varnish v1 -vcl {
 	import ${vmod_re2};
@@ -25,22 +25,29 @@ varnish v1 -vcl {
 		set resp.http.s-str-1 = s.string(1);
 		set resp.http.s-str-2 = s.string(2);
 		set resp.http.s-before-match = s.string();
+		set resp.http.s-which-b4-match = s.which();
 		set resp.http.s-foo-match = s.match("foo");
 		set resp.http.s-foo-n = s.nmatches();
+		set resp.http.s-foo-which = s.which();
 		set resp.http.s-foo-str = s.string();
 		set resp.http.s-bar-match = s.match("bar");
 		set resp.http.s-bar-n = s.nmatches();
+		set resp.http.s-bar-which = s.which();
 		set resp.http.s-bar-str = s.string();
 		set resp.http.s-bar-str-0 = s.string(0);
 		set resp.http.s-bar-str-1 = s.string(-1);
 		set resp.http.s-fail-match = s.match("fail");
 		set resp.http.s-fail-n = s.nmatches();
+		set resp.http.s-fail-which = s.which();
 		set resp.http.s-fail-str = s.string();
 		set resp.http.s-many-match = s.match("foobar");
 		set resp.http.s-many-n = s.nmatches();
 		set resp.http.s-many-str = s.string();
 		set resp.http.s-many-first = s.string(select=FIRST);
 		set resp.http.s-many-last = s.string(select=LAST);
+		set resp.http.s-which-many = s.which();
+		set resp.http.s-which-first = s.which(select=FIRST);
+		set resp.http.s-which-last = s.which(select=LAST);
 		set resp.http.s-outofrange = s.string(3);
 
 		set resp.http.n-str-1 = n.string(1);
@@ -60,22 +67,29 @@ client c1 {
 	expect resp.http.s-str-1 == "baz"
 	expect resp.http.s-str-2 == "quux"
 	expect resp.http.s-before-match == ""
+	expect resp.http.s-which-b4-match == "0"
 	expect resp.http.s-foo-match == "true"
 	expect resp.http.s-foo-n == 1
+	expect resp.http.s-foo-which == 1
 	expect resp.http.s-foo-str == "baz"
 	expect resp.http.s-bar-match == "true"
 	expect resp.http.s-bar-n == 1
+	expect resp.http.s-bar-which == 2
 	expect resp.http.s-bar-str == "quux"
 	expect resp.http.s-bar-str-0 == resp.http.s-bar-str
 	expect resp.http.s-bar-str-1 == resp.http.s-bar-str
 	expect resp.http.s-fail-match == "false"
 	expect resp.http.s-fail-n == 0
+	expect resp.http.s-fail-which == 0
 	expect resp.http.s-fail-str == ""
 	expect resp.http.s-many-match == "true"
 	expect resp.http.s-many-n == 2
 	expect resp.http.s-many-str == ""
 	expect resp.http.s-many-first == "baz"
 	expect resp.http.s-many-last == "quux"
+	expect resp.http.s-which-many == 0
+	expect resp.http.s-which-first == 1
+	expect resp.http.s-which-last == 2
 	expect resp.http.s-outofrange == ""
 	expect resp.http.n-str-1 == ""
 	expect resp.http.n-str-2 == ""
@@ -89,8 +103,11 @@ logexpect l1 -v v1 -d 1 -g vxid -q "VCL_Error" {
 	expect 0 * Begin req
 
 	expect * = VCL_Error "^vmod re2 error: s.string.. called without prior match$"
+	expect * = VCL_Error "^vmod re2 error: s.which.. called without prior match$"
+	expect * = VCL_Error "^vmod re2 error: s.which.0.: previous match was unsuccessful$"
 	expect * = VCL_Error "^vmod re2 error: s.string.0.: previous match was unsuccessful$"
 	expect * = VCL_Error "^vmod re2 error: s.string.0.: 2 successful matches$"
+	expect * = VCL_Error "^vmod re2 error: s.which.0.: 2 successful matches$"
 	expect * = VCL_Error "^vmod re2 error: s.string.3.: set has 2 patterns$"
 	expect * = VCL_Error "^vmod re2 error: n.string.1.: No strings were set for n$"
 	expect * = VCL_Error "^vmod re2 error: n.string.2.: No strings were set for n$"

src/vmod_re2.c

@@ -860,6 +860,14 @@ get_match_idx(VRT_CTX, struct vmod_re2_set *set, VCL_INT n, VCL_ENUM selects,
 	return task->matches[idx];
 }
 
+VCL_INT
+vmod_set_which(VRT_CTX, struct vmod_re2_set *set, VCL_ENUM selects)
+{
+	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
+	CHECK_OBJ_NOTNULL(set, VMOD_RE2_SET_MAGIC);
+	return get_match_idx(ctx, set, 0, selects, "which") + 1;
+}
+
 VCL_STRING
 vmod_set_string(VRT_CTX, struct vmod_re2_set *set, VCL_INT n, VCL_ENUM selects)
 {

src/vmod_re2.vcc

@@ -850,6 +850,8 @@ Example::
               + " patterns from the set");
   }
 
+$Method INT .which(ENUM {FIRST, LAST} select=0)
+
 $Method STRING .string(INT n=0, ENUM {FIRST, LAST} select=0)
 
 Returns the string associated with the `nth` pattern added to the set,