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- Subject: Re: numeric captures (string.find)
- From: Rici Lake <lua@...>
- Date: Tue, 14 Sep 2004 17:00:47 -0500
On 14-Sep-04, at 4:34 PM, Asko Kauppi wrote:
Would it be hard to make 'string.find()' return true numbers (not
strings with numerical contents, as now):
What do you think - would it get any votes?
Not from me :)
First of all, there are many strings of digits which are not "numbers"
-- id numbers, telephone numbers, postal codes (in some countries),
credit card numbers, etc. Note that you cannot reliably round-trip such
a sequence -- it may have too many digits for the precision of Number,
or it may have leading zeros. So getting a number instead of the string
Furthermore, there are many numbers which are not simply sequences of
digits -- negative numbers, floating point numbers, etc. The patterns
to recognise these are complicated; it is actually easier to just match
the possible character sequence and then verify with tonumber().
I wouldn't object to some % escape that used the c library's numeric
recognition algorithm and returned a real number -- although I'm not
sure that it would be worthwhile -- but magic behaviour on (%d+) is not
a good idea, imho. (And also tricky to check for while parsing the