[cl-ppcre-devel] Roles of scanner vs. parser vs. lexer?

[Derek Peschel]

Hi everybody,

I've been reading the CL-PPCRE docs and code to get a clear specification
of the syntax.  Ultimately I'd like to add syntax highlighting for CL-PPCRE
regexps to the Climacs text editor.

But there seems to be a certain amount of defensive or sloppy programming
(things being done in more than one place).  The scanner knows something
about skipping # comments but the lexer does too.  The lexer has code
to ignore \E markers but I get the impression the scanner removes them
before the lexer starts.  If this kind of duplication does exist, is there
a useful reason for it?

-- Derek