NAME
Math::PlanePath::Base::Digits  helpers for digit based paths
SYNOPSIS
use Math::PlanePath::Base::Digits 'digit_split_lowtohigh';
foreach my $digit (digit_split_lowtohigh ($n, 16)) {
}
DESCRIPTION
This is a few generic helper functions for paths based on digits or powering.
They're designed to work on plain Perl integers and floats and there's some special case support for Math::BigInt
.
EXPORTS
Nothing is exported by default but each function below can be as in the usual Exporter style,
use Math::PlanePath::Base::Digits 'round_down_pow';
(But not parameter_info_radix2()
, for the reason described below.)
FUNCTIONS
Generic
($power, $exponent) = round_down_pow ($n, $radix)

Return the power of
$radix
equal to or less than$n
. For example($pow, $exp) = round_down_pow (260, 2); # $pow==256 # the next lower power # $exp==8 # the exponent in that power # 2**8=256 is next below 260
@digits = digit_split_lowtohigh ($n, $radix)
@bits = bit_split_lowtohigh ($n)

Return a list of digits from
$n
in base$radix
, or in binary. For example,@digits = digit_split_lowtohigh (12345, 10); # @digits = (5,4,3,2,1) # decimal digits low to high
If
$n==0
then the return is an empty list. The current code expects$n >= 0
."lowtohigh" in the name tries to make it clear which way the digits are returned.
reverse()
can be used to get high to low instead (see "reverse" in perlfunc).bit_split_lowtohigh()
is the same asdigit_split_lowtohigh()
called with radix=2. $n = digit_join_lowtohigh ($arrayref, $radix)
$n = digit_join_lowtohigh ($arrayref, $radix, $zero)

Return a value made by joining digits from
$arrayref
in base$radix
. For example,@digits = (5,4,3,2,1) # decimal digits low to high $n = digit_split_lowtohigh (\@digits, 10); # $n == 12345
Optional
$zero
can be a 0 of an overloaded number type such asMath::BigInt
to give a returned$n
of that type.
Subclassing
$aref = parameter_info_array()

Return an arrayref of a
radix
parameter, default 2. This is designed to be imported into a PlanePath subclass as itsparameter_info_array()
method.package Math::PlanePath::MySubclass; use Math::PlanePath::Base::Digits 'parameter_info_array';
The arrayref is
[ { name => 'radix', share_key => 'radix_2', display => 'Radix', type => 'integer', minimum => 2, default => 2, width => 3, description => 'Radix (number base).', } ]
$href = Math::PlanePath::Base::Digits::parameter_info_radix2()

Return the single
radix
parameter hashref from the info above. This can be used when a subclass wants the radix parameter and other parameters too,package Math::PlanePath::MySubclass; use constant parameter_info_array => [ { name => 'something_else', type => 'integer', default => '123', }, Math::PlanePath::Base::Digits::parameter_info_radix2(), ];
If the "description" part should be more specific or more detailed then it could be overridden with for example
{ %{Math::PlanePath::Base::Digits::parameter_info_radix2()}, description => 'Radix, for both something and something.', },
This function is not exportable since it's meant for a oneoff call in an initializer and so no need to import it for repeated use.
SEE ALSO
Math::PlanePath, Math::PlanePath::Base::Generic
HOME PAGE
http://user42.tuxfamily.org/mathplanepath/index.html
LICENSE
Copyright 2010, 2011, 2012, 2013, 2014 Kevin Ryde
This file is part of MathPlanePath.
MathPlanePath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.
MathPlanePath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with MathPlanePath. If not, see <http://www.gnu.org/licenses/>.