Version

Functions for parsing and matching versions against requirements.

A version is a string in a specific format or a Version generated after parsing via Version.parse/1.

Although Elixir projects are not required to follow SemVer, they must follow the format outlined on SemVer 2.0 schema.

Versions

In a nutshell, a version is represented by three numbers:

MAJOR.MINOR.PATCH

Pre-releases are supported by optionally appending a hyphen and a series of period-separated identifiers immediately following the patch version. Identifiers consist of only ASCII alphanumeric characters and hyphens ([0-9A-Za-z-]):

"1.0.0-alpha.3"

Build information can be added by appending a plus sign and a series of dot-separated identifiers immediately following the patch or pre-release version. Identifiers consist of only ASCII alphanumeric characters and hyphens ([0-9A-Za-z-]):

"1.0.0-alpha.3+20130417140000.amd64"

Struct

The version is represented by the Version struct and fields are named according to SemVer 2.0: :major, :minor, :patch, :pre, and :build. You can read those fields but you should not create a new Version directly via the struct syntax. Instead use the functions in this module.

Requirements

Requirements allow you to specify which versions of a given dependency you are willing to work against. Requirements support the common comparison operators such as >, >=, <, <=, and == that work as one would expect, and additionally the special operator ~> described in detail further below.

# Only version 2.0.0
"== 2.0.0"

# Anything later than 2.0.0
"> 2.0.0"

Requirements also support and and or for complex conditions:

# 2.0.0 and later until 2.1.0
">= 2.0.0 and < 2.1.0"

Since the example above is such a common requirement, it can be expressed as:

"~> 2.0.0"

~> will never include pre-release versions of its upper bound, regardless of the usage of the :allow_pre option, or whether the operand is a pre-release version. It can also be used to set an upper bound on only the major version part. See the table below for ~> requirements and their corresponding translations.

~> | Translation :————- | :——————— ~> 2.0.0 | >= 2.0.0 and < 2.1.0 ~> 2.1.2 | >= 2.1.2 and < 2.2.0 ~> 2.1.3-dev | >= 2.1.3-dev and < 2.2.0 ~> 2.0 | >= 2.0.0 and < 3.0.0 ~> 2.1 | >= 2.1.0 and < 3.0.0

The requirement operand after the ~> is allowed to omit the patch version, allowing us to express ~> 2.1 or ~> 2.1-dev, something that wouldn’t be allowed when using the common comparison operators.

When the :allow_pre option is set false in Version.match?/3, the requirement will not match a pre-release version unless the operand is a pre-release version. The default is to always allow pre-releases but note that in Hex :allow_pre is set to false. See the table below for examples.

Requirement | Version | :allow_pre | Matches :————- | :———- | :—————- | :—— ~> 2.0 | 2.1.0 | true or false | true ~> 2.0 | 3.0.0 | true or false | false ~> 2.0.0 | 2.0.5 | true or false | true ~> 2.0.0 | 2.1.0 | true or false | false ~> 2.1.2 | 2.1.6-dev | true | true ~> 2.1.2 | 2.1.6-dev | false | false ~> 2.1-dev | 2.2.0-dev | true or false | true ~> 2.1.2-dev | 2.1.6-dev | true or false | true >= 2.1.0 | 2.2.0-dev | true | true >= 2.1.0 | 2.2.0-dev | false | false >= 2.1.0-dev | 2.2.6-dev | true or false | true

Function compare/2

Compares two versions.

Returns :gt if the first version is greater than the second one, and :lt for vice versa. If the two versions are equal, :eq is returned.

Pre-releases are strictly less than their corresponding release versions.

Patch segments are compared lexicographically if they are alphanumeric, and numerically otherwise.

Build segments are ignored: if two versions differ only in their build segment they are considered to be equal.

Raises a Version.InvalidVersionError exception if any of the two given versions are not parsable. If given an already parsed version this function won’t raise.

Examples

Version.compare("2.0.1-alpha1", "2.0.0")

Version.compare("1.0.0-beta", "1.0.0-rc1")

Version.compare("1.0.0-10", "1.0.0-2")

Version.compare("2.0.1+build0", "2.0.1")

Version.compare("invalid", "2.0.1")

Function compile_requirement/1

Compiles a requirement to an internal representation that may optimize matching.

The internal representation is opaque.

Function match?/3

Checks if the given version matches the specification.

Returns true if version satisfies requirement, false otherwise. Raises a Version.InvalidRequirementError exception if requirement is not parsable, or a Version.InvalidVersionError exception if version is not parsable. If given an already parsed version and requirement this function won’t raise.

Options

• :allow_pre (boolean) - when false, pre-release versions will not match unless the operand is a pre-release version. Defaults to true. For examples, please refer to the table above under the “Requirements” section.

Examples

Version.match?("2.0.0", "> 1.0.0")

Version.match?("2.0.0", "== 1.0.0")

Version.match?("2.1.6-dev", "~> 2.1.2")

Version.match?("2.1.6-dev", "~> 2.1.2", allow_pre: false)

Version.match?("foo", "== 1.0.0")

Version.match?("2.0.0", "== == 1.0.0")

Function parse/1

Parses a version string into a Version struct.

Examples

{:ok, version} = Version.parse("2.0.1-alpha1")
version

Version.parse("2.0-alpha1")

Function parse!/1

Parses a version string into a Version.

If string is an invalid version, a Version.InvalidVersionError is raised.

Examples

Version.parse!("2.0.1-alpha1")

Version.parse!("2.0-alpha1")

Function parse_requirement/1

Parses a version requirement string into a Version.Requirement struct.

Examples

{:ok, requirement} = Version.parse_requirement("== 2.0.1")
requirement

Version.parse_requirement("== == 2.0.1")

Function parse_requirement!/1

Parses a version requirement string into a Version.Requirement struct.

If string is an invalid requirement, a Version.InvalidRequirementError is raised.

Examples

Version.parse_requirement!("== 2.0.1")

Version.parse_requirement!("== == 2.0.1")