NAME
    Hash::Key::Quote - Utility routines related to quoting of hash keys

VERSION
    This document describes version 0.002 of Hash::Key::Quote (from Perl
    distribution Hash-Key-Quote), released on 2019-07-10.

DESCRIPTION
FUNCTIONS
  should_quote_hash_key($str) => bool
    Return true if $str should be quoted as a hash key when placed before
    the fat comma ("=>") operator. According to the perlop documentation:

     The "=>" operator (sometimes pronounced "fat comma") is a synonym for the comma
     except that it causes a word on its left to be interpreted as a string if it
     begins with a letter or underscore and is composed only of letters, digits and
     underscores. This includes operands that might otherwise be interpreted as
     operators, constants, single number v-strings or function calls. If in doubt
     about this behavior, the left operand can be quoted explicitly.

    This means strings like "and" or "v1" need not be quoted.

    But there are several other cases where a string needs not be quoted.
    For example, numbers except in these cases:

     012        # perl will interpret it as a positive octal literal
     -012       # perl will interpret it as a negative octal literal
     1_000_000  # perl will strip the underscores from number
     -1_000_000 # ditto
     1_0e10     # ditto
     -1_0e10    # ditto
     +123       # perl will strip the + sign
     -+123      # ditto
     1e2        # perl will normalize it to "100"
     1_00a      # not a valid number, must be quoted

    Another example is non-number string that begins with a dash and
    followed only by letters/numbers/underscores, e.g. "-foo".

    For simplicity, you should probably just always quote. But if you only
    want to quote when necessary, this routine can help you.

HOMEPAGE
    Please visit the project's homepage at
    <https://metacpan.org/release/Hash-Key-Quote>.

SOURCE
    Source repository is at
    <https://github.com/perlancar/perl-Hash-Key-Quote>.

BUGS
    Please report any bugs or feature requests on the bugtracker website
    <https://rt.cpan.org/Public/Dist/Display.html?Name=Hash-Key-Quote>

    When submitting a bug or request, please include a test-file or a patch
    to an existing test-file that illustrates the bug or desired feature.

SEE ALSO
    perlop

    Data::Dump from which this code is extracted.

AUTHOR
    perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2019 by perlancar@cpan.org.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

