string.gsub accepting a callable userdata

[steve donovan <steve.j.donovan@...>]

Hi all,

string.gsub is one of the most powerful Lua functions we have, and the
substitution may be a string, a table, or a function.

It would be useful if this list could be extended to include callable
userdata - in most language interop situations I've encountered,
foreign functions are represented in this way on the Lua side.

(It would be too confusing to allow callable _tables_ of course)

steve d.