Re: Help with LPeg

[Sean Conner <sean@...>]

It was thus said that the Great Christopher Tallman once stated:
> Hi, I'm trying to accomplish a string find/replace on a Lua file,
> essentially updating the values stored in a table with new values,
> while preserving the structure, layout, and comments of the file (I
> don't want to just serialize the table, since that would drop
> formatting and comments).
> 
> For example, let's say I have a file Lua file containing the following:
> 
> <code>
> -- Range descriptions
> ranges = {
>   [1] = {0, 100}, -- primary
>   [2] = {101, 500}, -- secondary
>   [3] = {500,1000}, -- final range
> }
> </code>
> 
> I'm trying to write a lua program that will read in this file and the
> values in the subtables with new values and write the file back out,
> preserving the rest of the file.  I'm pretty sure this is a simple
> problem to solve with LPeg, but I've never used it before.  I could
> probably get this working with plain regex, but I would like to learn
> something new in the process and try doing it with LPeg.  Any advice
> or pointers on how I can get this to work?  Good resources for someone
> unfamiliar with PEG?

  I have a couple of Github repositories of example LPeg code.  The first is
the code from an LPeg talk I gave at work.  It has several examples of
parsing dates using various features of LPeg:

	https://rawgit.com/dlaurie/lua-notes/master/lpeg-brief.html

  The second repository contains code to parse some Internet formats (email,
IP addresses, JSON files and INI files):

	https://github.com/spc476/LPeg-Parsers

  This should give you a feeling for what LPeg looks like and how one goes
about using it.

  -spc