Re: [ANN] LuaCSV

[Thomas Lauer <thomas.lauer@...>]

Hi Steve,

I have not yet looked into your code but one question springs to mind
immediately: have you done some benchmarks (informal or otherwise), eg
with a pure-Lua solution that works with LPEG or some other
pattern-matching algorithms? I am confident that a low-level interface
would be faster than pure Lua... the question is how much faster?

-- 
cheers  thomasl

steve donovan <steve.j.donovan@gmail.com> wrote:
----original message----
From: steve donovan <steve.j.donovan@gmail.com>
Date: Mon, 3 Aug 2009 13:33:55 +0200
Subj: [ANN] LuaCSV
> Hi all,
> 
> Recently we were talking about CSV format again, and there was a
> suggestion that we needed a fast low-level extension [1]
> 
> Well, [2] is an attempt to supply that extension.  It does the quoting
> rules correctly, as far as I can tell, but does not do the case where
> multiline records are encoded in double-quotes.  That is an exercise
> for another day.
> 
> It provides an iterator, which returns the _same table_  each time. So
> for a little inconvenience in some cases, one gets absolutely minimal
> hit on Lua memory. The returned table does have a copy() method,
> however.
> 
> By default, it looks at the first data line and works out whether they
> are to convertible to numbers. Thereafter, it keeps a mask of these
> fields and converts them. This will particuarly help you if you have a
> lot of numerical data to bring in.  (You can always switch it off if
> it guesses incorrectly)
> 
> Tested on Debian 32-bit (gcc), and Windows XP (MS compiler).  The zip
> contains a dll for those poor Windows souls without compilers.
> 
> steve d.
> 
> 1 http://lua-users.org/lists/lua-l/2000-11/msg00134.html
> 2 http://mysite.mweb.co.za/residents/sdonovan/lua/luaCSV.zip