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CLOG - The Common Lisp Omnificent GUI
(github.com)
Lisp (historically LISP) is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. Originally specified in 1958, Lisp is the second-oldest high-level programming language. Only Fortran is older, by one year.
CLOG is very enjoyable to work with. I only have nice things to tell about developer experience and quality of documentation.