When comparing XLISP vs Guile, the Slant community recommends Guile for most people. In the question“What are the best scheme implementations?” Guile is ranked 2nd while XLISP is ranked 23rd. The most important reason people chose Guile is:
Guile makes it easy for users of your application to write extensions without needing to understand the plumbing of your program.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Light weight
Light weight and runs almost anywhere including in dos.
Pro Easy to customize and extend applications
Guile makes it easy for users of your application to write extensions without needing to understand the plumbing of your program.
Pro GNU's official extension language
Chances are a system running enough GNU software will already have it installed.
Pro Excellent documentation
The documentation provides conceptual overviews, tutorials, and a detailed reference for all commands, functions, and operators.
Pro Fantastic interface to C, C++ in both directions, embedding guile in C/C++ and embedding C/C++ in guile
Cons
Con Dynamic scope
Some will complain about the dynamic scope.
Con Weak copyleft
LGPL