A reference to a step or recipe: "cookbook:path".

iex> Composer.Ref.parse("composer_lab:ash/postgres")
{:ok, %Composer.Ref{cookbook: "composer_lab", path: "ash/postgres"}}

iex> Composer.Ref.parse("ash/postgres")
{:ok, %Composer.Ref{cookbook: nil, path: "ash/postgres"}}

A path is one or more /-separated segments of [a-z0-9_]. Input is normalized from - to _, so daisy-ui and daisy_ui are the same name. The hex: cookbook also accepts a private-repo package such as hex:oban.oban_pro.

Sources

A hex: reference may name where the package comes from, after an @, as mix igniter.install does:

iex> Composer.Ref.parse("hex:ash@3.5")
{:ok, %Composer.Ref{cookbook: "hex", path: "ash", source: [version: "~> 3.0"]}}

iex> Composer.Ref.parse("hex:my-lib@path:../my-lib")
{:ok, %Composer.Ref{cookbook: "hex", path: "my_lib", source: [path: "../my-lib"]}}

• @<version> - @3.5.0 is "== 3.5.0", a partial version such as @3.5 is "~> 3.0" (Igniter's rule), and a requirement with an operator (@~>3.5) is kept as written
• @github:owner/repo, or @github:owner/repo@ref
• @git:<url>
• @path:<path>

The reference is split on its first @, so the spec may contain :, @ and -; only the package name is normalized. A source is the same keyword list as the version:/github:/git:/path: options of a recipe entry (see Composer.Recipe). Any other reference with an @ is invalid.

Parsing never creates atoms.