Synopsis A scheme is used in a location for wich no provider has been registered.
Description Rascal:Locations provide very flexible ways to access files and external data sources. There any many protocols (called schemes) that can be used (e.g., file, http, home and many others). This error is generated when an unknown scheme is used.

Remedy: Use an existing scheme.
Examples Misspelling the scheme for Rascal's standard library (which is std) gives an error when the location is used:
rascal>import IO;
|stdin:///|(14,34,<1,14>,<1,48>): IO("Unsupported scheme standard")
	at *** somewhere ***(|stdin:///|(14,34,<1,14>,<1,48>))
	at readFileLines(|stdin:///|(14,34,<1,14>,<1,48>))

This is fixed by using the proper scheme name:
list[str]: ["@license{","  Copyright (c) 2009-2013 CWI","  All rights reserved. This program and the accompanying materials","  are made available under the terms of the Eclipse Public License v1.0","  which accompanies this distribution, and is available at","","}","@contributor{Jurgen J. Vinju - - CWI}","@contributor{Paul Klint - - CWI}","//START","module demo::basic::Hello","","import IO;","","void hello() {","   println(\"Hello world, this is my first Rascal program\");","}"]
Is this page unclear, or have you spotted an error? Please add a comment below and help us to improve it. For all other questions and remarks, visit