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

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Module Version: 1.14   Source   Latest Release: Number-Fraction-2.01

# NAME

Number::Fraction - Perl extension to model fractions

# SYNOPSIS

```  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'```

# ABSTRACT

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

# DESCRIPTION

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'.

## Experimental Support for Exponentiation

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)```

# METHODS

## import

Called when module is `use`d. Use to optionally install constant handler.

## unimport

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

## new

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.

## to_string

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

## to_num

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

## add

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.

## mult

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

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.

## div

Divide 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.

## exp

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.

## abs

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

None by default.

perldoc overload

# AUTHOR

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

# COPYRIGHT AND LICENSE

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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