Subject: procedure-argumets does not work with advanced evaled lambdas

From: Stefan Israelsson Tampe <[email-masked]>
Date: Thu, 1 Mar 2012 22:58:53 +0100

Here is a transcript of the problem

scheme@(guile-user)> (define f (lambda* (#:key x) x))
scheme@(guile-user)> (procedure-arguments f)

$53 = ((required) (optional) (keyword (#:x . 0)) (allow-other-keys? . #f)
(rest . #f))

scheme@(guile-user)> (define f (eval '(lambda* (#:key x) x)
(current-module)))
scheme@(guile-user)> (procedure-arguments f)

$54 = ((required) (optional) (keyword) (allow-other-keys? . #f) (rest .
%args))

Why is this important.

As an example trying to port rackets contract you have functions that take
a function
and return a new function with checks according to a contract added. the
functionality
is the same but input and output is checked. Now to use this, information
about the
keywords are needed in order to do some sanity checks that can be done at
construction
time. But if we eval a lambda and use that, we saw above that the
information is not added.
and the nice idea with contracts is broken.

Solution idea:

mod eval.scm and as described in session.scm make sure to add a 'arglist
procedure-property
to the newly constructed lambda with the appropriate information added.

Regards
Stefan