From: William Djaja Tjokroaminata <billtj@...>
Date: 2002-08-14T21:52:34+09:00
Subject: Re: Is There an Inverse of 'rb_define_method'?

nobu.nokada@softhome.net wrote:
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> It's done at compile time, but not run time.
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Agreed.

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> However, there are many other functions with non-negative
> arity, "func(self, arg1)", "func(self, arg1, arg2)" and so on.
> To invoke C function corresponding to ruby method, you must
> distinguish them, and call_cfunc() does it.
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You mean, for user-defined functions in Ruby, the Ruby parser can actually
generate non-negative arity C functions?  I mean, for example, for

    def my_func (arg1, arg2, arg3 = val3)

the parser can generate a corresponding C function like

    rb_define_method (classmod, "my_func", func_ptr, 3)

?  In my mind, for any user-defined Ruby function, at least the parser
will "equivalently" only generate

    rb_define_method (classmod, "my_func", func_ptr, -1);

with

    rb_scan_args (argc, argv, "21", &arg1, &arg2, &arg3);

(I said equivalently because it is not obvious how to get func_ptr from a
user-defined Ruby function; probably through some intermediary proc
object.)  This is rather hard to believe; then probably reading parse.c
will be interesting.

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> And a user can redefine methods, then the methods don't have
> corresponding C functions.
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This may be a little bit tricky, because then it means I have to obtain
the function pointer only after the parsing (of all user scripts) is
completely done.

Regards,

Bill