Ystok-URI is a portable Uniform Resource Identifier (URI) library for Common Lisp programs. It parses URI strings according to RFC3986 and supports percent-encoding/decoding in full.

A Uniform Resource Identifier is a string of characters used to identify a resource. Such identification enables interaction with representations of the resource over a network (typically the World Wide Web) using specific protocols.


Ystok-URI requires

Ystok-URI is required by YstokHTML and YstokHelp.


The source code was tested on the following Lisp implementations:

Download and installation

The latest version of Ystok-URI 2.0.007 is available at The distribution package contains the two system definition files:

To run tests, do the following:

  1. Make sure the tester is loaded, for example, push :tester into the *features* list before loading ACL-Compat.
  2. Compile and load the file test.lisp.
  3. Evaluate the form (ystok.uri.test:do-tests).