[Date Prev][Date Next][Thread Prev][Thread Next]
- Subject: Re: Lexer and syntax highlighter powered by LPeg
- From: Peter Odding <xolox@...>
- Date: Sat, 07 Apr 2007 07:54:18 +0200
You mean my code isn’t documented clearly enough? I’ll add some more comments,
though my problem is always deciding which parts need them, since LPeg already
has clearly defined operators and spelling everything out in human language
quickly gets redundant.
I am having trouble understanding the following. (I don't think it's
documented very clearly)
> P "'" * ((1 - S "'\r\n\f\\") + (P '\\' * 1)) ^ 0 * "'"
What is the P '\\' * 1 for? Does it match a \ and then any single character?
Correct. A plain number matches/consumes it’s own number of characters. I should
probably have matched the full escape but I didn’t because I don’t think there
are any error cases to handle. This would be the correct pattern:
local escape = S ""\r\n\f\\"
local sq_string = P "'" * ((1-escape) + (P'\\' * escape))^0 * "'"
also just noticed that the above could be made faster (I think):
local sq_string = P "'" * ((1-escape)^0 + (P'\\' * escape))^0 * "'"
Have a nice day,
- Peter Odding