LPeg: fold capture in re
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- Subject: LPeg: fold capture in re
- From: Александр Машин <alex.mashin@...>
- Date: 2015年8月03日 20:08:00 +0700
I've always thought of the re module as a demo application: see here,
this is how one should build a large, complex LPeg program.
You seem to prefer re and fall back to straight LPeg as a last resort.
And he is not alone. The reasons to prefer re are
1) more concise syntax,
2) natural serialisability--you can easily store re grammars and their
parts in a database,
3) greater flexibility in assembling grammars from chunks of any kind:
only concatenation is needed.
spc (Except you still can't do a folding capture in re ... )
I think fold captures can be added to re:
"~>" * S* m.Cg(Def/ getdef* m.Cc(m.Cf))
(diff: http://traditio.wiki/w/index.php?diff=524882&oldid=517695)
And example of usage (http://traditio.wiki/wiki/Module:Test4):
local serialise= require "Module:Test".serialise
local re= require "Module:re"
return {
show= function ()
local p= re.compile([==[
list <- ( {| |} pair* ) ~> rawset
pair <- {: name space equals space value :} ( space sep space )?
name <- { %w+ }
value <- { %w+ }
equals <- '='
sep <- [,;]
space <- %s*
]==], { rawset = rawset })
local r= p:match"a=b, c = hi; next = pi"
return serialise(r)
end
}
show () returns:
table {
a = b
c = hi
next = pi
}
This may be considered a feature request. Thanks in advance.
Alexander Mashin