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- Subject: Re: xml pull parser
- From: Adrian Sietsma <adrian_groups@...>
- Date: Tue, 22 Mar 2005 13:28:09 +1100
Aaron Brown wrote:
PA wrote:
At first glance there are 4 different ways to write a
"for" loop ( "=", "in", "in ipairs()", "in pairs()" ).
Let make that 5. There is a "in next()" as well. Sigh...
that is not correct : for ... in pairs(), in ipairs(), in next() are the
same thing as far as the language goes - each of pairs, ipairs, etc is a
function that returns an iterator function. also io.lines()
there are only 2 "for" constructs -
1/ the numeric for (PIL ch 4.3)
for var=exp1,exp2,exp3 do
something
end
will iterate for each value of var from exp1 to exp2 in steps of exp3
for i = 10,1,-1 do print(i) end
will loop from 10 to 1, decrementing.
(exp3 defaults to 1, which is reasonable, although one might expect it
to be nil)
2/ the generic for (PIL ch 7.2)
for <var-list> in <exp-list> do
something
end
most often used as
for var1, var2 in iterator_func do
something
end
where iterator_func is lines(), pairs(), ipairs() etc. this will loop
until iterator_func returns nil.
note that pairs()/ipairs() is evaluated ONCE - it returns a function
that is called each loop
Adrian
- References:
- xml pull parser, PA
- Re: xml pull parser, Adam D. Moss
- Re: xml pull parser, PA
- Re: xml pull parser, Javier Guerra Giraldez
- Re: xml pull parser, PA
- Re: xml pull parser, Javier Guerra
- Re: xml pull parser, PA
- Re: xml pull parser, Rici Lake
- Re: xml pull parser, PA
- Re: xml pull parser, PA
- Re: xml pull parser, Aaron Brown