Elixir v1.6.5 Version View Source

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.

Version parsing and requirements follow SemVer 2.0 schema.


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


Pre-releases are supported by appending -[0-9A-Za-z-\.]:


Build information can be added by appending +[0-9A-Za-z-\.]:



The version is represented by the Version struct and fields are named according to SemVer: :major, :minor, :patch, :pre, and :build.


Requirements allow you to specify which versions of a given dependency you are willing to work against. Requirements support common operators like >=, <=, >, ==, and friends that work as one would expect:

# 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. 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 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

When allow_pre: false is set, 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.

~> 2.1-dev2.2.0-devfalsetrue
~> 2.1.2-dev2.1.3-devfalsetrue
>= 2.1.0-dev2.2.3-devtruetrue

Link to this section Summary


Compares two versions

Compiles a requirement to its internal representation with :ets.match_spec_compile/1 for faster matching

Checks if the given version matches the specification

Parses a version string into a Version struct

Parses a version string into a Version

Parses a version requirement string into a Version.Requirement struct

Link to this section Types

Link to this type build() View Source
build() :: String.t() | nil
Link to this type matchable() View Source
matchable() ::
  {major :: major(), minor :: minor(), patch :: patch(), pre :: pre()}
Link to this type t() View Source
t() :: %Version{
  build: build(),
  major: major(),
  minor: minor(),
  patch: patch(),
  pre: pre()
Link to this type version() View Source
version() :: String.t() | t()

Link to this section Functions

Link to this function compare(version1, version2) View Source
compare(version(), version()) :: :gt | :eq | :lt

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.


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

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

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

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

iex> Version.compare("invalid", "2.0.1")
** (Version.InvalidVersionError) invalid version: "invalid"
Link to this function compile_requirement(req) View Source
compile_requirement(Version.Requirement.t()) :: Version.Requirement.t()

Compiles a requirement to its internal representation with :ets.match_spec_compile/1 for faster matching.

The internal representation is opaque and cannot be converted to external term format and then back again without losing its properties (meaning it can not be sent to a process on another node and still remain a valid compiled match_spec, nor can it be stored on disk).

Link to this function match?(version, requirement, opts \\ []) View Source
match?(version(), requirement(), keyword()) :: boolean()

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.


  • :allow_pre (boolean) - when false, pre-release versions will not match unless the operand is a pre-release version. See the table above for examples. Defaults to true.


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

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

iex> Version.match?("foo", "== 1.0.0")
** (Version.InvalidVersionError) invalid version: "foo"

iex> Version.match?("2.0.0", "== == 1.0.0")
** (Version.InvalidRequirementError) invalid requirement: "== == 1.0.0"
Link to this function parse(string) View Source
parse(String.t()) :: {:ok, t()} | :error

Parses a version string into a Version struct.


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

iex> Version.parse("2.0-alpha1")
Link to this function parse!(string) View Source
parse!(String.t()) :: t() | no_return()

Parses a version string into a Version.

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


iex> Version.parse!("2.0.1-alpha1")

iex> Version.parse!("2.0-alpha1")
** (Version.InvalidVersionError) invalid version: "2.0-alpha1"
Link to this function parse_requirement(string) View Source
parse_requirement(String.t()) :: {:ok, Version.Requirement.t()} | :error

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


iex> {:ok, requirement} = Version.parse_requirement("== 2.0.1")
iex> requirement
#Version.Requirement<== 2.0.1>

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