[Chicken-hackers] [PATCH] verify syntax in => cond clauses

[Evan Hanson]

This patch improves cond's behavior on clauses which contain `=>` but do
not match the precise definition of cond.

CHICKEN's current behavior is as follows:

    #;> (cond (#t =>))
    Error: (caddr) during expansion of (cond ...) - bad argument type: ()
    ...

I believe this behavior is incorrect, and should instead be, for
example:

    #;> (cond (#t =>))
    Error: unbound variable: =>
    ...
    #;> (define => 1)
    #;> (cond (#t =>))
    1
    #;> (cond (#t => 2 3))
    3

The attached patch simply verifies the length of cond clauses containing
arrows in order to handle cases such as these.

Evan

0001-verify-syntax-in-cond-clauses.patch
Description: Text document