add package pathrouter

1 files changed, 31 insertions, 0 deletions

diff --git a/pathrouter/variable.go b/pathrouter/variable.go
new file mode 100644
index 0000000..e712f46
--- /dev/null
+++ b/pathrouter/variable.go
@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: 2026 Stefan Majewsky <majewsky@gmx.net>
+// SPDX-License-Identifier: Apache-2.0
+
+package pathrouter
+
+import "go.xyrillian.de/gg/options"
+
+// Variable is a [Matcher] that accepts subpaths with at least one path element.
+// The value of the first path element will be collected into vars[name],
+// and the remaining subpath will have to be accepted by the next matcher.
+func Variable(name string, matcher Matcher) Matcher {
+	return variable(name, matcher.downcast())
+}
+
+func variable(name string, matcher realMatcher) Matcher {
+	return realMatcher{
+		minLength: matcher.minLength + 1,
+		maxLength: options.Map(matcher.maxLength, increment),
+		accept: func(path []string, vars map[string]string) HandlerFunc {
+			if len(path) == 0 || path[0] == "" {
+				return nil
+			}
+			handlerFunc := matcher.accept(path[1:], vars)
+			if handlerFunc == nil {
+				return nil
+			}
+			vars[name] = pathUnescape(path[0])
+			return handlerFunc
+		},
+	}
+}