Dennis Roberts wrote:

>Dan could you explain the difference between using regular expressions
>and a bonafide parser?
>  
>
He's just distinguishing between a parser which obeys an overall grammar 
and a parser made of regexps (little grammars).

Ruby's parser, for instance, leverages a parser generator (yacc) which 
is given the rules used to parse Ruby source code.

However, Regexps are often used in conjunction with Racc, a parser 
generator for Ruby.  So Regexps aren't always a bad thing, and in fact 
they can be used to add great flexibility (such as in feedparser.org), 
they just tend to leave lots of holes in the overall soundness of the 
parser.

_why