Questions regarding regexp module

[Daniel J. <dan...@gm...>]

I'm currently working on the regexp module (I'm still here in case
anyone wondered). I've a few questions / suggestions:

I think it would be good to have regexp-exec fail when there are more
matches than the number of possible return values and it was specified
to return the matches as multiple values. Currently, regexp-exec then
just returns the results as a list:

// ...
switch (rettype) {
  case ret_values:
    if (re_count < fixnum_to_V(Symbol_value(S(multiple_values_limit)))) {
      STACK_to_mv(re_count);
      break;
    } /* else FALLTHROUGH */
  case ret_list:   VALUES1(listof(re_count)); break;
// ...

This could lead to surprises, when e.g. calling:

(multiple-value-list (match some-pattern some-string))

When match returns multiple values, one get's a list with the
matches. But when - because of a different pattern - there are more
matches then suddenly this returns a list with the list of matches,
which could confuse code using the result. It's probably not that
critical as one needs to have a pattern with 127 sub-expressions
or more, though.


Next, currently regex-compile returns a foreign-pointer, and
regex-exec expects a foreign pointer. Thus I could supply regexp-exec
with a foreign pointer acquire from some other function, resulting in
undefined behavior (because regexp-exec blindly assumes it to be a
regex_t * ). AFAIK the policy for CLISP is to not just crash on such
errors.  As solution, I'd wrap the foreign pointer in a (defstruct
pattern pointer). Are there any objections against this?