Languages from the GNU project tend to have decent info pages (e.g. Guile, GCL, Libc). Perl also comes with perldoc, which is like manpages but instead of using

Languages from the GNU project tend to have decent info pages (e.g. Guile, GCL, Libc). Perl also comes with perldoc, which is like manpages but instead of using the man command you use the perldoc command.