Re: Lexer and syntax highlighter powered by LPeg

["Andy Stark" <AStark@...>]

Lua list <lua@bazar2.conectiva.com.br> writes:

>Andy Stark wrote:
>> Would it be feasible/desirable for a future version of Lua to use PEG
>> techniques (coded in C) in its own parser?
>What advantage would that bring? The Lua parser works already, right?

Yes, I noticed that too ;-)

Well, as I understand it, PEGs allow you to specify both lexical and
syntactic patterns, so there wouldn't need to be a separate lexer and
scanner in the parser. I'm thinking a PEG system might make the code
easier to understand and modify. Maybe also smaller code size and speed
for the parser? Both are very important for Lua.

>There would certainly be some bootstrapping problems since LPeg uses Lua 
>operators to compose patterns :). I know of a language which bootstraps
>itself with some minimal operators but I can't seem to find it right now.

It's been commonplace for compilers to be self-hosting for some time (BCPL
was the first, I think). The Java compiler is written in Java, C# written
in C# and Perl 6 (if it ever materialises) is designed the same way. The
bootstrapping problem must be surmountable somehow.

&.


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