Re: Problem with table key iteration when string keys are unpredictable
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- Subject: Re: Problem with table key iteration when string keys are unpredictable
- From: Dirk Laurie <dirk.laurie@...>
- Date: 2013年5月22日 20:08:29 +0200
2013年5月22日 marbux <marbux@gmail.com>:
> My thanks to you all. I will test each of these methods and go with
> the one that seems the most foolproof, given other code in the script.
>
> A special thanks for noticing that the script also needs to escape
> magic characters, which I had not yet caught.
Since nobody has up to now supported Sean's suggestion of LPEG,
I'll do so now. I recently put in the required amount of activation energy
to get my LPEG competence going, and the reaction is now exothermic.
In non-chemical terms, there's a steep learning curve but once you
reach the plateau you just keep going effortlessly.
Building a pattern that tries several possibilities in a prescribed order
is one of the most basic LPEG constructs: a1+a2+a3+...+an
Prescribing the replacement is hardly less basic:
a1/b1
Saying "move up one character if there is no match" is easy too
a1+1
Repeat indefinitely:
a1^0
Do the substitutions and leave the rest unchanged:
lpeg.Cs(P)
E.g.
Cs, P = lpeg.Cs, lpeg.P
pat = Cs((P"ABC"/"abc" + P"AB"/"de" + P"A"/"f"+P(1)/".")^0)
print (pat:match"ABCBAABCABABCABCBABCBCBAB")
abc.fabcdeabcabc.abc...de