diff --git a/web/pattern.go b/web/pattern.go
index 69f5654..903f6fd 100644
--- a/web/pattern.go
+++ b/web/pattern.go
@@ -19,7 +19,14 @@ type regexpPattern struct {
 func (p regexpPattern) Prefix() string {
 	return p.prefix
 }
-func (p regexpPattern) Match(r *http.Request, c *C, dryrun bool) bool {
+func (p regexpPattern) Match(r *http.Request, c *C) bool {
+	return p.match(r, c, false)
+}
+func (p regexpPattern) Run(r *http.Request, c *C) {
+	p.match(r, c, false)
+}
+
+func (p regexpPattern) match(r *http.Request, c *C, dryrun bool) bool {
 	matches := p.re.FindStringSubmatch(r.URL.Path)
 	if matches == nil || len(matches) == 0 {
 		return false
@@ -148,8 +155,13 @@ type stringPattern struct {
 func (s stringPattern) Prefix() string {
 	return s.literals[0]
 }
-
-func (s stringPattern) Match(r *http.Request, c *C, dryrun bool) bool {
+func (s stringPattern) Match(r *http.Request, c *C) bool {
+	return s.match(r, c, true)
+}
+func (s stringPattern) Run(r *http.Request, c *C) {
+	s.match(r, c, false)
+}
+func (s stringPattern) match(r *http.Request, c *C, dryrun bool) bool {
 	path := r.URL.Path
 	var matches map[string]string
 	if !dryrun && len(s.pats) > 0 {
diff --git a/web/pattern_test.go b/web/pattern_test.go
index 2ea3c90..6b2575f 100644
--- a/web/pattern_test.go
+++ b/web/pattern_test.go
@@ -162,12 +162,13 @@ func TestPatterns(t *testing.T) {
 }
 
 func runTest(t *testing.T, p Pattern, test patternTest) {
-	result := p.Match(test.r, test.c, false)
+	result := p.Match(test.r, test.c)
 	if result != test.match {
 		t.Errorf("Expected match(%v, %#v) to return %v", p,
 			test.r.URL.Path, test.match)
 		return
 	}
+	p.Run(test.r, test.c)
 
 	if !reflect.DeepEqual(test.c, test.cout) {
 		t.Errorf("Expected a context of %v, instead got %v", test.cout,
diff --git a/web/router.go b/web/router.go
index e5ed9dd..5c3c041 100644
--- a/web/router.go
+++ b/web/router.go
@@ -78,10 +78,13 @@ type Pattern interface {
 	Prefix() string
 	// Returns true if the request satisfies the pattern. This function is
 	// free to examine both the request and the context to make this
-	// decision. After it is certain that the request matches, this function
-	// should mutate or create c.URLParams if necessary, unless dryrun is
-	// set.
-	Match(r *http.Request, c *C, dryrun bool) bool
+	// decision. Match should not modify either argument, and since it will
+	// potentially be called several times over the course of matching a
+	// request, it should be reasonably efficient.
+	Match(r *http.Request, c *C) bool
+	// Run the pattern on the request and context, modifying the context as
+	// necessary to bind URL parameters or other parsed state.
+	Run(r *http.Request, c *C)
 }
 
 func parsePattern(p interface{}) Pattern {
@@ -144,13 +147,14 @@ type routeMachine struct {
 }
 
 func matchRoute(route route, m method, ms *method, r *http.Request, c *C) bool {
-	if !route.pattern.Match(r, c, true) {
+	if !route.pattern.Match(r, c) {
 		return false
 	}
 	*ms |= route.method
 
 	if route.method&m != 0 {
-		return route.pattern.Match(r, c, false)
+		route.pattern.Run(r, c)
+		return true
 	}
 	return false
 }
diff --git a/web/router_test.go b/web/router_test.go
index 442903e..59955cb 100644
--- a/web/router_test.go
+++ b/web/router_test.go
@@ -64,9 +64,11 @@ func (t testPattern) Prefix() string {
 	return ""
 }
 
-func (t testPattern) Match(r *http.Request, c *C, dryrun bool) bool {
+func (t testPattern) Match(r *http.Request, c *C) bool {
 	return true
 }
+func (t testPattern) Run(r *http.Request, c *C) {
+}
 
 var _ Pattern = testPattern{}
 
@@ -174,9 +176,11 @@ type rsPattern struct {
 func (rs rsPattern) Prefix() string {
 	return rs.prefix
 }
-func (rs rsPattern) Match(_ *http.Request, _ *C, _ bool) bool {
+func (rs rsPattern) Match(_ *http.Request, _ *C) bool {
 	return rs.i >= *rs.counter
 }
+func (rs rsPattern) Run(_ *http.Request, _ *C) {
+}
 
 func (rs rsPattern) ServeHTTP(_ http.ResponseWriter, _ *http.Request) {
 	rs.ichan <- rs.i