Boot (more precisely newer dialect called Shoe) is used internally in FriCAS for some of the interpreter and compiler code. Here is a detailed description of the Boot Language This is a simple example of Boot programming. Define a function. fricas (1) -> <boot> pairBoot(a, Now call it. fricas pairBoot(1, That's my first Boot function! You can now write for example: boot foobar(x, boot You cannot )read the file /var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/7491012761112044243-25px003.boot because your user-level is not is not high enough. For more information about your user-level, And call it with fricas integer(foobar(2, In FriCAS (from revision 1049 on) the simplest way to compile and load boot code is to write it into a file and then call something like: )read FILE.boot To debug Boot code add diagnostic printouts using SAY, like boot print_bar(x) == SAY(["print_bar", boot You cannot )read the file /var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/6147864484223767607-25px005.boot because your user-level is not is not high enough. For more information about your user-level, fricas )boot print_bar(123) Note: Unlike other printing functions One can also add breakpoints using |