Looks interesting. I would take the liberty of adding it directly to the Arc wiki git at: http://git.nex-3.com/arc-wiki.git , unless you want to do that yourself^^.
I've noticed you've added a 'filter function which duplicates the functionality of 'keep, except that 'filter does not (testify ...) the predicate function. It doesn't seem to be used by make-br-fn, so I'm wondering if you would like it retained.
I've been looking at it, and it looks like it's added quite a few functions to the global namespace. Either we need to implement namespaces (or modules) quite well, or we need to make local functions easier to create.
Hmm, that's a good point. I think that andmap and ormap are generically useful; the rest should probably be hiding. I could wrap all of make-br-fns in (with (free? (rfn free? ...))), etc., but then it would have to recreate the procedures each time... prefixing the procedures with * mbf- might be one way to deal with it, so they don't overload a common name. I don't know what the best option is (until we actually have modules, in which case it's clear)--thoughts?
Well, the lisplike we use in the office doesn't have modules either, so our convention (actually just my, since no one else takes that language seriously) is to put a prefix name like yours.
Btw there might be a bug in 'arglist-vars - it uses (is arglist 'cons), maybe you meant (isa ...) ?
LOL. In my off-time in the office I'm building a package system for that lisplike, basing off a macro that must enclose all forms that need to use packages; basically what it does is add the package name to the symbols that have been imported from the package.
Also, for 'arglist-frees - from what I can hack, it tries to extract used variables in argument lists for optional arguments. So for example, your intent is that:
(arglist-frees '(x (o y (some-var))))
=> (some-var)
However, to extract the subexpression, you use car:cdar. I don't understand why.