Download of Scheme Widget Library (SWL) 1.3 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. Scheme Widget Library (SWL) for Mac is sometimes referred to as "swl".
The application lies within Productivity Tools, more precisely Office Tools. We recommend checking the downloaded files with any free antivirus. Commonly, this program's installer has the following filename: swl1.3-i3osx-1.pkg.tar.gz. The most popular version of Scheme Widget Library (SWL) for Mac is 1.3. This free Mac app is a product of Cadence Research Systems.
From the developer:
The Scheme Widget Library (SWL) is a free windowing and graphics package for Chez Scheme developed in the Indiana University Computer Science Department with support from the National Science Foundation and Cadence Research Systems. It includes an object system for Scheme, a threaded windowing and graphics library, and various tools, including a window-based REPL (read-eval-print loop) window, a simple editor, a source-file viewer, and a document viewer.
You may want to check out more Mac applications, such as QSS Widget, Calculator Widget or .::LvL - Quake 3 Widget, which might be related to Scheme Widget Library (SWL).