Math::String::Charset 1.27

Math::String::Charset is a simple charset for Math::String objects.

SYNOPSIS

use Math::String::Charset;

$a = new Math::String::Charset; # default a-z
$b = new Math::String::Charset [a..z]; # same
$c = new Math::String::Charset
{ start => [a..z], sep => }; # with between chars

print $b->length(); # a-z => 26

# construct a charset from bigram table, and an initial set (containing
# valid start-characters)
# Note: After an a, either an b, c or a can follow, in this order
# After an d only an a can follow
$bi = new Math::String::Charset ( {
start => a..d,
bi => {
a => [ b, c, a ],
b => [ c, b ],
c => [ a, c ],
d => [ a, ],
q => [ ], # q will be automatically in end
}
end => [ a, b, ],
} );
print $bi->length(); # a,b => 2 (cross of end and start)
print scalar $bi->class(2); # count of combinations with 2 letters
# will be 3+2+2+1 => 8

$d = new Math::String::Charset ( { start => [a..z],
minlen => 2, maxlen => 4, } );

print $d->first(0),"n"; # undef, too short
print $d->first(1),"n"; # undef, to short
print $d->first(2),"n"; # aa

$d = new Math::String::Charset ( { start => [a..z] } );

print $d->first(0),"n"; #
print $d->first(1),"n"; # a
print $d->last(1),"n"; # z
print $d->first(2),"n"; # aa

This module lets you create an charset object, which is used to contruct Math::String objects. This object knows how to handle simple charsets as well as complex onex consisting of bi-grams (later tri and more).

In case of more complex charsets, a reference to a Math::String::Charset::Nested or Math::String::Charset::grouped will be returned.

The default charset is the set containing "abcdefghijklmnopqrstuvwxyz" (thus producing always lower case output).