Re: [ANN] LuaCSV

[Joshua Jensen <jjensen@...>]

----- Original Message -----
From: Luiz Henrique de Figueiredo
Date: 8/3/2009 6:49 AM

have you done some benchmarks (informal or otherwise), eg with a pure-Lua
solution that works with LPEG or some other pattern-matching algorithms?
    

There's code in PiL: http://www.lua.org/pil/20.4.html 
  

This is based on some help from the list, PiL, and some techniques on the LPEG recipes page.  It does build one "massive" table of the contents of the .csv file, a tremendous difference over Steve's implementation, I believe.

-Josh

---------------------------------------------------
-- lexers/csv.lua
--
-- Given a .csv file, convert it into a Lua table.
module(..., package.seeall)

local lpeg = require 'lpeg'
local C, Cs, Ct, P, S = lpeg.C, lpeg.Cs, lpeg.Ct, lpeg.P, lpeg.S

local eol = P'\r\n' + P'\n'
local quoted_field = '"' * Cs(((P(1) - '"') + P'""' / '"')^0) * '"'
local unquoted_field = C((1 - S',\r\n"')^0)
local field = quoted_field + unquoted_field
local record = Ct(field * (',' * field)^0)
local nonemptyrecord = #P(1 - eol) * record
local records = Ct((record * eol)^0 * nonemptyrecord^-1) * -1
local _one_line_record_ = record * (eol + -1)

function parse_line(line)
   assert(type(line) == 'string', 'bad argument #1 (expected string)')
   return lpeg.match(one_line_record, line)
end

-- public interface
getmetatable(getfenv(1)).__call = function(self, input)
   assert(type(input) == 'string', 'bad argument #1 (expected string)')
   return lpeg.match(records, input)
end