On 2016-12-24 11:52, Mark Morgan Lloyd wrote: > regexes are useful. Very much so, and I’m far from being an expert. But I am finding more and more uses for them, the more I use them.
> BUT FFS DOCUMENT WHAT YOU'RE DOING FOR PEOPLE WHO DON'T UNDERSTAND THEM! The same can be said for standard code too. At least with regex, there are plenty of tools that explain what they do, and what each part means. For example: http://rick.measham.id.au/paste/explain.pl?regex=%5Cb%5B-%2B%5D%3F%5B0-9%5D%2B%28%3F%3A%5C.%5B0-9%5D%2B%29%3F%5Cb NODE EXPLANATION -------------------------------------------------------------------------------- \b the boundary between a word char (\w) and something that is not a word char -------------------------------------------------------------------------------- [-+]? any character of: '-', '+' (optional (matching the most amount possible)) -------------------------------------------------------------------------------- [0-9]+ any character of: '0' to '9' (1 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- (?: group, but do not capture (optional (matching the most amount possible)): -------------------------------------------------------------------------------- \. '.' -------------------------------------------------------------------------------- [0-9]+ any character of: '0' to '9' (1 or more times (matching the most amount possible)) -------------------------------------------------------------------------------- )? end of grouping -------------------------------------------------------------------------------- \b the boundary between a word char (\w) and something that is not a word char That tells you exactly what each part of the following regex means: ⌜\b[-+]?[0-9]+(?:\.[0-9]+)?\b⌟ Note: I wrap the regex with ⌜ and ⌟ character to denote the start and end of the regex. Some people get confused when you use double quotes. I believe Perl or egrep or something can output the exact same “regex explanation” information from the command line. Regards, Graeme -- fpGUI Toolkit - a cross-platform GUI toolkit using Free Pascal http://fpgui.sourceforge.net/ My public PGP key: http://tinyurl.com/graeme-pgp _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
