# NAME

Math::Inequalities::Parser - Minimum and maximum values allowed by an inequality.

# SYNOPSIS

```
use Math::Inequalities::Parser;
my ($min, $max) = parse_inequality( ' 10 < n < 20 ' );
# $min = 11
# $max = 19
```

# DESCRIPTION

Tiny library for parsing integer maximum and minimum out when given an arbitrary inequality.

Because getting this simple thing right was far harder than it looked, and I never want to have to think about it again.

# FUNCTIONS

## parse_inequality

Parses an inequality string and returns a list of two values, the minimum and the maxium value that string will allow.

# TYPES OF INEQUALITY

## VALUE

The simplest type, a single value, e.g. `42 = Min 42, Max 42`

.

## n < VALUE

Maximum is VALUE - 1, Minimum is undefined, e.g. `n < 42 = Min undef, Max 41`

.

## n > VALUE

Minimum is VALUE +1, Maximum is undefined, e.g. `n > 42 = Min 43, Max undef`

.

## n <= VALUE

Maximum is VALUE, Minimum is undefined, e.g. `n < 42 = Min undef, Max 42`

.

## n >= VALUE

Minimum is VALUE, Maximum is undefined, e.g. `n > 42 = Min 42, Max undef`

.

## Cases with VALUE, followed by N.

Handled as above, but with minimum and maximum reversed as expected.

## VALUE1 < n < VALUE2

Minimum is VALUE1 + 1, maximum is VALUE2 - 1, e.g `42 < n < 200 = Min 43, Max 199`

.

# BUGS

- Does not handle
`VALUE1 <= n <= VALUE2`

or similar. Patches welcome. - Does not complain at impossible
`<VALUE1 < n < VALUE 2`

> combinations (e.g.`5 < n < 4`

) which result in a higher minumum than the maxiumum. Patches welcome. - Does not work with negative numbers. Patches welcome.
- Always uses
`n`

as the number identifier, this should be configureable at import time. - Uses Exporter (should use Sub::Exporter)
**DOES NOT**work with floating point numbers. I consider this a feature.

# AUTHORS

Tomas Doran (t0m) `<bobtfish@bobtfish.net>`

Dave Lambley

# COPYRIGHT & LICENSE

Copyright 2011 the above author(s).

This sofware is free software, and is licensed under the same terms as perl itself.