lpeg accumulator
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- Subject: lpeg accumulator
- From: Gavin Wraith <gavin@...>
- Date: 2013年9月18日 20:17:51 +0100
I tried to use lpeg.Cf with a non-numeric accumulator (in
lpeg 0.12) thus:
#!lua
local digit = lpeg.R "09"
local num = lpeg.C(digit^1)/tonumber
local comma = lpeg.C ","
local acc = function (t,x,y)
t[1] = t[1] + x
t[2] = t[2] + y
end
local vec = lpeg.Cf (num * comma * num, acc)
local pat = lpeg.Cc { 0, 0} * (vec + 1)^0
local t = pat:match "Try (3,4) plus (100,200)"
print ("(", t[1], ",", t[2], ")")
but it spat it out with "attempt to index local 't' (a number value)".
Are there good reasons why lpeg.Cf only works with number values?
You can probably see what I am trying to do. Is the problem my
poor coding or the type restriction on lpeg.Cf?
Is the restriction necessary?
--
Gavin Wraith (gavin@wra1th.plus.com)
Home page: http://www.wra1th.plus.com/