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Re: Pre-RFC: builtin:: functions for detecting numbers vs strings

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Dan Book
March 11, 2022 21:25
Re: Pre-RFC: builtin:: functions for detecting numbers vs strings
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On Fri, Mar 11, 2022 at 4:19 PM William Lindley <>

> In all this discussion, what happens when reading a file containing the
> line:
> 01730
> which is the postal code for my hometown.  This "looks like" a number
> but if treated like one, the leading zero is liable be dropped, leaving
> invalid postcode
> 1730
> In more-pathological cases, 01730 could be interpreted as an octal
> number (984 decimal).
> It is disheartening that Perl's "be forgiving in what you accept; be
> strict at what you output" is violated by so many newer protocols.
Depends on how it is used in Perl syntax. If you write that as the literal
value: `my $x = 01730;` then you have not assigned the zipcode, but an
octal number. If you write it as a string: `my $x = '01730';` then it will
be a string containing your intended zip code. Thus you must represent
zipcodes as strings. Regardless, this is not very relevant to the proposed
functions; if anything, they allow a serializer to avoid misrepresenting
such a value, as long as you created it properly.


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