Test some examples from the docs, and fix the examples.

README.rst

@@ -129,9 +129,9 @@ lines. For example::
       # substitution operation, each of which removes a
       # parameter.
       new rewrite = selector.set();
-      rewrite.add("/alpha/beta", regex="(\?.*)\bfoo=[^&]+(.*)$");
-      rewrite.add("/delta/gamma", regex="(\?.*)\bbar=[^&]+(.*)$");
-      rewrite.add("/epsilon/zeta", regex="(\?.*)\bbaz=[^&]+(.*)$");
+      rewrite.add("/alpha/beta", regex="(\?.*)\bfoo=[^&]+&?(.*)$");
+      rewrite.add("/delta/gamma", regex="(\?.*)\bbar=[^&]+&?(.*)$");
+      rewrite.add("/epsilon/zeta", regex="(\?.*)\bbaz=[^&]+&?(.*)$");
 
   }
 
@@ -788,7 +788,7 @@ Example::
   }
 
   if (rewrite.hasprefix(req.url)) {
-     set req.url = rewrite.sub(req.url, "\1/\3/\2/");
+     set req.url = rewrite.sub(req.url, "\1/\3/\2/", select=LAST);
   }
 
   # /foo/1/2/* is rewritten as /foo/2/1/*

src/tests/sub.vtc

@@ -169,3 +169,92 @@ client c1 {
 } -run
 
 logexpect l1 -wait
+
+# Examples from the docs
+varnish v1 -vcl {
+	import ${vmod_selector};
+	import std;
+	backend b { .host = "${bad_ip}"; }
+
+	sub vcl_init {
+		new rewrite1 = selector.set();
+		rewrite1.add("/alpha/beta", regex="(\?.*)\bfoo=[^&]+&?(.*)$");
+		rewrite1.add("/delta/gamma", regex="(\?.*)\bbar=[^&]+&?(.*)$");
+		rewrite1.add("/epsilon/zeta", regex="(\?.*)\bbaz=[^&]+&?(.*)$");
+
+		new rewrite2 = selector.set();
+		rewrite2.add("/foo/", regex="^(/foo)/([^/]+)/([^/]+)/");
+		rewrite2.add("/foo/bar/", regex="^(/foo/bar)/([^/]+)/([^/]+)/");
+		rewrite2.add("/foo/bar/baz/",
+		    regex="^(/foo/bar/baz)/([^/]+)/([^/]+)/");
+	}
+
+	sub vcl_recv {
+		return (synth(200));
+	}
+
+	sub vcl_synth {
+		if (rewrite1.hasprefix(req.url)) {
+			set resp.http.Rewrite = rewrite1.sub(req.url, "\1\2");
+		}
+		if (rewrite2.hasprefix(req.url)) {
+			set resp.http.Rewrite
+			    = rewrite2.sub(req.url, "\1/\3/\2/" ,select=LAST);
+		}
+		return (deliver);
+	}
+}
+
+client c1 {
+	txreq -url "/alpha/beta/foo?x=y&foo=4711&baz=quux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/alpha/beta/foo?x=y&baz=quux"
+
+	txreq -url "/delta/gamma/foo?x=y&bar=4711&baz=quux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/delta/gamma/foo?x=y&baz=quux"
+
+	txreq -url "/epsilon/zeta/foo?x=y&baz=4711&quux=quux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/epsilon/zeta/foo?x=y&quux=quux"
+
+	txreq -url "/alpha/beta/foo?foo=4711&x=y&baz=quux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/alpha/beta/foo?x=y&baz=quux"
+
+	# Doesn't remove a trailing ampersand, don't worry about it.
+	txreq -url "/alpha/beta/foo?x=y&baz=quux&foo=4711"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/alpha/beta/foo?x=y&baz=quux&"
+
+	# URL is unchanged if the regex doesn't match.
+	txreq -url "/alpha/beta/foo?x=y&baz=quux"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/alpha/beta/foo?x=y&baz=quux"
+
+	txreq -url "/alpha/beta/foo"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/alpha/beta/foo"
+
+	txreq -url "/foo/1/2/3/4"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/foo/2/1/3/4"
+
+	txreq -url "/foo/bar/1/2/3/4"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/foo/bar/2/1/3/4"
+
+	txreq -url "/foo/bar/baz/1/2/3/4"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.Rewrite == "/foo/bar/baz/2/1/3/4"
+} -run

src/vmod_selector.vcc

@@ -99,9 +99,9 @@ lines. For example::
       # substitution operation, each of which removes a
       # parameter.
       new rewrite = selector.set();
-      rewrite.add("/alpha/beta", regex="(\?.*)\bfoo=[^&]+(.*)$");
-      rewrite.add("/delta/gamma", regex="(\?.*)\bbar=[^&]+(.*)$");
-      rewrite.add("/epsilon/zeta", regex="(\?.*)\bbaz=[^&]+(.*)$");
+      rewrite.add("/alpha/beta", regex="(\?.*)\bfoo=[^&]+&?(.*)$");
+      rewrite.add("/delta/gamma", regex="(\?.*)\bbar=[^&]+&?(.*)$");
+      rewrite.add("/epsilon/zeta", regex="(\?.*)\bbaz=[^&]+&?(.*)$");
 
   }
 
@@ -664,7 +664,7 @@ Example::
   }
 
   if (rewrite.hasprefix(req.url)) {
-     set req.url = rewrite.sub(req.url, "\1/\3/\2/");
+     set req.url = rewrite.sub(req.url, "\1/\3/\2/", select=LAST);
   }
 
   # /foo/1/2/* is rewritten as /foo/2/1/*