in reply to Apocalypse 5 and regexes
All the apocalypsi up to this point have been incremental, but this one
changes everything in the regex world. In fact the system that Larry
proposes is so far beyond what computer sceince calls regular
expressions, it should be given a new name.
I would propose grammar expressions, or gramexes,
because this system will allow one to
parse full recursive grammars easily. I'd guess Larry chose
angle brackets because that is what is often used in
specifying nonterminals in a BNF grammar.
From the implementation point of view, such a system will
require the full intermixing of perl and gramex code at
the Parrot bytecode level, which will probably slow down
matching relative to the perl5 regex engine.
From a user point of view, I think the difference between temp
and let and local and my will be pretty confusing for most
Previously, grammars had been parsed by perl code for the
parsing and regexes for the lexing. Larry seems to be betting
that a specialized subsystem for grammars will be more
readable and perhaps faster than the old way.
Times will certainly be interesting for perl6 gramex implementors.