NAME

       "Tickit::StringPos" - store string position counters

SYNOPSIS

        use Tickit::StringPos;
        use Tickit::Utils qw( string_count );

        my $pos = Tickit::StringPos->zero;
        string_count( "Here is a message", $pos );

        print "The message consumes ", $pos->columns, " columns\n";

DESCRIPTION

       Instances in this object class store four position counters that relate to counting
       strings.

       The "bytes" member counts UTF-8 bytes which encode individual codepoints. For example the
       Unicode character U+00E9 is encoded by two bytes 0xc3, 0xa9; it would increment the bytes
       counter by 2 and the "codepoints" counter by 1.

       The "codepoints" member counts individual Unicode codepoints.

       The "graphemes" member counts whole composed graphical clusters of codepoints, where
       combining accents which count as individual codepoints do not count as separate graphemes.
       For example, the codepoint sequence U+0065 U+0301 would increment the "codepoint" counter
       by 2 and the "graphemes" counter by 1.

       The "columns" member counts the number of screen columns consumed by the graphemes. Most
       graphemes consume only 1 column, but some are defined in Unicode to consume 2.

       Instances are also used to store count limits, where any member may be set to -1 to
       indicate no limit in that counter.

CONSTRUCTORS

   zero
          $pos = Tickit::StringPos->zero

       Returns a new instance with all counters set to zero.

   limit_bytes
   limit_codepoints
   limit_graphemes
   limit_columns
          $pos = Tickit::StringPos->limit_bytes( $bytes )

          $pos = Tickit::StringPos->limit_codepoints( $codepoints )

          $pos = Tickit::StringPos->limit_graphemes( $graphemes )

          $pos = Tickit::StringPos->limit_columns( $columns )

       Return a new instance with one counter set to the given limit and the other three counters
       set to -1.

METHODS

   bytes
   codepoints
   graphemes
   columns
          $bytes = $pos->bytes

          $codepoints = $pos->codepoints

          $graphemes = $pos->graphemes

          $columns = $pos->columns

       Return the current value the counters.

AUTHOR

       Paul Evans <leonerd@leonerd.org.uk>