use v6.*;

unit module P5lcfirst:ver<0.0.10>:auth<zef:lizmat>;

proto sub lcfirst(|) is export {*}
multi sub lcfirst(--> Str:D) {
    lcfirst(CALLERS::<$_>)
}
multi sub lcfirst(Str() $string --> Str:D) {
    $string
      ?? $string.substr(0,1).lc ~ $string.substr(1)
      !! $string
}

proto sub ucfirst(|) is export {*}
multi sub ucfirst(--> Str:D) {
    ucfirst(CALLERS::<$_>)
}
multi sub ucfirst(Str() $string --> Str:D) {
    $string
      ?? $string.substr(0,1).uc ~ $string.substr(1)
      !! $string
}

=begin pod

=head1 NAME

Raku port of Perl's lcfirst() / ucfirst() built-ins

=head1 SYNOPSIS

  use P5lcfirst;

  say lcfirst "FOOBAR"; # fOOBAR
  with "ZIPPO" {
      say lcfirst;  # zIPPO
  }

  say ucfirst "foobar"; # Foobar
  with "zippo" {
      say ucfirst;  # Zippo
  }

=head1 DESCRIPTION

This module tries to mimic the behaviour of Perl's C<lcfirst> and C<ucfirst>
built-ins as closely as possible in the Raku Programming Language.

=head1 ORIGINAL PERL 5 DOCUMENTATION

    lcfirst EXPR
    lcfirst Returns the value of EXPR with the first character lowercased.
            This is the internal function implementing the "\l" escape in
            double-quoted strings.

            If EXPR is omitted, uses $_.

            This function behaves the same way under various pragmata, such as
            in a locale, as "lc" does.

    ucfirst EXPR
    ucfirst Returns the value of EXPR with the first character in uppercase
            (titlecase in Unicode). This is the internal function implementing
            the "\u" escape in double-quoted strings.

            If EXPR is omitted, uses $_.

            This function behaves the same way under various pragma, such as
            in a locale, as "lc" does.

=head1 PORTING CAVEATS

In future language versions of Raku, it will become impossible to access the
C<$_> variable of the caller's scope, because it will not have been marked as
a dynamic variable.  So please consider changing:

    lcfirst;

to either:

    lcfirst($_);

or, using the subroutine as a method syntax, with the prefix C<.> shortcut
to use that scope's C<$_> as the invocant:

    .&lcfirst;

=head1 AUTHOR

Elizabeth Mattijsen <[email protected]>

Source can be located at: https://github.com/lizmat/P5lcfirst . Comments and
Pull Requests are welcome.

=head1 COPYRIGHT AND LICENSE

Copyright 2018, 2019, 2020, 2021 Elizabeth Mattijsen

Re-imagined from Perl as part of the CPAN Butterfly Plan.

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.

=end pod

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