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Changing the Library (Collection) Search Path

Problem

You want to change the path in which PltScheme searches for library (collection) paths.

Solution

There are two main ways of doing this:

1. Programmatically change the parameter current-library-collections-path
2. Set the PLTCOLLECTS environment variable

An example of the former that appends the path ../lib to the search path is:

(require (lib "etc.ss"))
(current-library-collection-paths
 (append
  (current-library-collection-paths)
  (list
   (simplify-path (build-path (this-expression-source-directory)
                              'up "lib")))))

For the second approach, the PLTCOLLECTS environment variable holds a list of paths to search: a string holding paths that are separated by colon (semi-colon on Windows). An empty path in this string indicates where the default collects path goes, so:

• /foo/collects means search for libraries only in /foo/collects. If you want to use the standard PLT libraries, then they should be included in this directory.
• :/foo/collects (;/foo/collects on Windows) will search for libraries in the default location and then in /foo/collects, which means that you can put additional libraries there.
• /foo/collects: will search for libraries first in /foo/collects and then in the default location, making it possible to override libraries if they exist there.

Note: Starting from PLT Scheme v301.12, the PLT executables search for the collects path relative to the executable. You can override this using the new -X (or --collects) command-line argument.

Discussion

Comments about this recipe

The first method won't work inside a module - module expands at compile time, while (current-library-collection-paths ...) gets evaluated at run time. In such case only the second approach works.

-- YinSoChen - 21 Apr 2007

Contributors

-- NoelWelsh - 06 May 2006

-- EliBarzilay - 07 May 2006