Dave Cross >
Number-Fraction-1.14 >
Number::Fraction

Module Version: 1.14
Number::Fraction - Perl extension to model fractions

use Number::Fraction; my $f1 = Number::Fraction->new(1, 2); my $f2 = Number::Fraction->new('1/2'); my $f3 = Number::Fraction->new($f1); # clone my $f4 = Number::Fraction->new; # 0/1

or

use Number::Fraction ':constants'; my $f1 = '1/2'; my $f2 = $f1; my $one = $f1 + $f2; my $half = $one - $f1; print $half; # prints '1/2'

Number::Fraction is a Perl module which allows you to work with fractions in your Perl programs.

Number::Fraction allows you to work with fractions (i.e. rational numbers) in your Perl programs in a very natural way.

It was originally written as a demonstration of the techniques of overloading.

If you use the module in your program in the usual way

use Number::Fraction;

you can then create fraction objects using `Number::Fraction-`

new> in a number of ways.

my $f1 = Number::Fraction->new(1, 2);

creates a fraction with a numerator of 1 and a denominator of 2.

my $f2 = Number::Fraction->new('1/2');

does the same thing but from a string constant.

my $f3 = Number::Fraction->new($f1);

makes `$f3`

a copy of `$f1`

my $f4 = Number::Fraction->new; # 0/1

creates a fraction with a denominator of 0 and a numerator of 1.

If you use the alterative syntax of

use Number::Fraction ':constants';

then Number::Fraction will automatically create fraction objects from string constants in your program. Any time your program contains a string constant of the form `\d+/\d+`

then that will be automatically replaced with the equivalent fraction object. For example

my $f1 = '1/2';

Having created fraction objects you can manipulate them using most of the normal mathematical operations.

my $one = $f1 + $f2; my $half = $one - $f1;

Additionally, whenever a fraction object is evaluated in a string context, it will return a string in the format x/y. When a fraction object is evaluated in a numerical context, it will return a floating point representation of its value.

Fraction objects will always "normalise" themselves. That is, if you create a fraction of '2/4', it will silently be converted to '1/2'.

Version 1.13 of Number::Fraction adds experimental support for exponentiation operations. If a Number::Fraction object is used as the left hand operand of an exponentiation expression then the value returned will be another Number::Fraction object - if that makes sense. In all other cases, the expression returns a real number.

Currently this only works if the right hand operand is an integer (or a Number::Fraction object that has a denominator of 1). Later I hope to extend this so support so that a Number::Fraction object is returned whenever the result of the expression is a rational number.

For example:

'1/2' ** 2 # Returns a Number::Fraction ('1/4') '2/1' ** '2/1' Returns a Number::Fraction ('4/1') '2/1' ** '1/2' Returns a real number (1.414213) 0.5 ** '2/1' Returns a real number (0.25)

Called when module is `use`

d. Use to optionally install constant handler.

Be a good citizen and uninstall constant handler when caller uses `no Number::Fraction`

.

Constructor for Number::Fraction object. Takes the following kinds of parameters:

- A single Number::Fraction object which is cloned.
- A string in the form 'x/y' where x and y are integers. x is used as the numerator and y is used as the denominator of the new object.
- Two integers which are used as the numerator and denominator of the new object.
- A single integer which is used as the numerator of the the new object. The denominator is set to 1.
- No arguments, in which case a numerator of 0 and a denominator of 1 are used.

Returns `undef`

if a Number::Fraction object can't be created.

Returns a string representation of the fraction in the form "numerator/denominator".

Returns a numeric representation of the fraction by calculating the sum numerator/denominator. Normal caveats about the precision of floating point numbers apply.

Add a value to a fraction object and return a new object representing the result of the calculation.

The first parameter is a fraction object. The second parameter is either another fraction object or a number.

Multiply a fraction object by a value and return a new object representing the result of the calculation.

The first parameter is a fraction object. The second parameter is either another fraction object or a number.

Subtract a value from a fraction object and return a new object representing the result of the calculation.

The first parameter is a fraction object. The second parameter is either another fraction object or a number.

Divide a fraction object by a value and return a new object representing the result of the calculation.

Raise a Number::Fraction object to a power.

The first argument is a number fraction object. The second argument is another Number::Fraction object or a number. If the second argument is an integer or a Number::Fraction object containing an integer then the value returned is a Number::Fraction object, otherwise the value returned is a real number.

Returns a copy of the given object with both the numerator and denominator changed to positive values.

None by default.

perldoc overload

Dave Cross, <dave@mag-sol.com>

Copyright 2002-8 by Dave Cross

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

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