semver.lua/README.md

# semver.lua

[![Build Status](https://travis-ci.org/kikito/semver.lua.svg?branch=master)](https://travis-ci.org/kikito/semver.lua)

Semantic versioning for Lua.

See http://semver.org/ for details about semantic versioning.

# Documentation

``` lua
local v = require 'semver'

-- two ways of creating it: with separate parameters, or with one string
v1 = v(1,0,0)
v2_5_1 = v('2.5.1')

-- When using one string one can skip the parenthesis:
v2_5_1 = v'2.5.1' -- valid in Lua

-- major, minor and patch attributes
v2_5_1.major -- 2
v2_5_1.minor -- 5
v2_5_1.patch -- 1

-- prereleases:
a = v(1,0,0,'alpha')
a.prerelease -- 'alpha'
b = v('1.0.0-beta')
b.prerelease -- 'beta'

-- builds
c = v(1,0,0,nil,'build-1')
c.build -- 'build-1'

d = v('0.9.5+no.extensions.22')
d.build -- 'no.extensions.22'

-- comparison & sorting
v'1.2.3' == v(1,2,3)         -- true
v'1.2.3' < v(4,5,6)          -- true
v'1.2.3-alpha' < v'1.2.3'    -- true
v'1.2.3' < v'1.2.3+build.1'  -- false, builds are ignored when comparing versions in semver
-- (see the "notes" section for more informaion about version comparison)

-- "pessimistic upgrade" operator: ^
-- a ^ b returns true if it's safe to update from a to b
v'2.0.1' ^ v'2.5.1' -- true - it's safe to upgrade from 2.0.1 to 2.5.1
v'1.0.0' ^ v'2.0.0' -- false - 2.0.0 is not supposed to be backwards-compatible
v'2.5.1' ^ v'2.0.1' -- false - 2.5.1 is more modern than 2.0.1.

-- getting newer versions
v(1,0,0):nextPatch() -- v1.0.1
v(1,2,3):nextMinor() -- v1.3.0 . Notice the patch resets to 0
v(1,2,3):nextMajor() -- v2.0.0 . Minor and patch are reset to 0

```

# Installation

Just copy the semver.lua file wherever you want it (for example on a lib/ folder). Then write this in any Lua file where you want to use it. You must assign the require to a global or local variable (I use a local `v`):

``` lua
local v = require 'semver'
```

Using `v` allows for the nice string syntax: `v'1.2.3-alpha'`.

Please make sure that you read the license, too (for your convenience it's now included at the beginning of the semver.lua file).

# Notes about version comparison

Version comparison is done according to the semver 2.0.0 specs:

Major, minor, and patch versions are always compared numerically.

Pre-release precedence MUST be determined by comparing each dot-separated identifier as follows:

* Identifiers consisting of only digits are compared numerically
* Identifiers with letters or dashes are compared lexically in ASCII sort order.
* Numeric identifiers always have lower precedence than non-numeric identifiers

Builds are ignored when calculating precedence: version 1.2.3 and 1.2.3+build5 are considered equal.

# Specs

This project uses "busted":http://olivinelabs.com/busted/ for its specs. If you want to run the specs, you will have to install telescope first. Then just execute the following from the root inspect folder:

```
busted
```

# Changelog

## v1.1.1:
* Removed global variable which was declared by mistake
* Changed spec tool from telescope to busted
* Changed README format from textile to markdown

## v.1.2.0:
* Fix error: builds were being used for comparison, but according with semver 2.0.0 they should be ignored (so v'1.0.0+build1' is equal to v'1.0.0+build2')
* Fix several errors and inconsistencies in the way the comparisons where implemented.
* Added a lot more tests to cover more edge cases when comparing versions

## v.1.2.1
* Fix error on pessimistic update operator when applied to a 0.x.x version