March 2011 Archives

Perl and Parsing 8: The Where and Why of Rejection

Why Perl is Just Not That Into Your Syntax

In a previous post, I noted that Perl often cannot precisely locate syntax errors in its scripts. Still less can it identify the exact problem. In this post, I will demonstrate an experimental utility which does pinpoint Perl syntax errors, precisely indicating where and what the problem is.

Here's my example from …

Progress on Marpa::XS

A Faster Marpa

For those who don't know, Marpa is a parser generator which parses any grammar you can write in BNF. If the grammar is one of those which can be parsed by yacc, by recursive descent or as a regular expression, Marpa parses it in linear time.

Marpa's core algorithm does no system calls. It is almost 100% pointer twiddling. There is no floating point, and very little integer arithmetic. It's as if it was made to order to show C in …

About Jeffrey Kegler

user-pic I blog about Perl, with a focus on parsing and Marpa, my parsing algorithm based on Jay Earley's.