Add Elm manager.

lib/license_finder/package.rb

@@ -193,3 +193,4 @@ def log_activation(activation)
 require 'license_finder/packages/composer_package'
 require 'license_finder/packages/conda_package'
 require 'license_finder/packages/pubspec_package'
+require 'license_finder/packages/elm_package'

lib/license_finder/package_manager.rb

@@ -181,3 +181,4 @@ def log_to_file(prep_cmd, contents)
 require 'license_finder/package_managers/composer'
 require 'license_finder/package_managers/conda'
 require 'license_finder/package_managers/pub'
+require 'license_finder/package_managers/elm'

lib/license_finder/package_managers/elm.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require 'json'
+
+module LicenseFinder
+  class Elm < PackageManager
+    ELM_HOME = (ENV['ELM_HOME'] || '/.elm').freeze
+
+    def current_packages
+      elm_json_content = JSON.parse File.read(detected_package_path)
+      elm_version = elm_json_content['elm-version']
+      packages = packages_from_json(elm_json_content, elm_version)
+    end
+
+    def possible_package_paths
+      [project_path.join('elm.json')]
+    end
+
+    private
+
+    def packages_from_json(elm_version, elm_json)
+      packages = (elm_json.dig('dependencies', 'direct') || {})
+        .merge(elm_json.dig('dependencies', 'indirect') || {})
+        .map do |(author_name, version)|
+          author, name = author_name.split('/')
+          package_elm_json = find_package_elm_json(ELM_HOME, elm_version, author, name, version)
+          ElmPackage.from_elm_json(name, version, author, package_elm_json)
+        end
+    end
+
+    def find_package_elm_json(home, elm_version, author, name, version)
+      path = File.join(home, elm_version, 'packages', @author, name, @version, 'elm.json')
+      JSON.parse File.open(path)
+    end
+  end
+end

lib/license_finder/packages/elm_package.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+module LicenseFinder
+  class ElmPackage < Package
+    attr_reader :author
+
+    def self.from_elm_json(name, version, author, elm_json_content)
+      new(name,
+        version,
+        author,
+        spec_licenses: Package.license_names_from_standard_spec(elm_json_content),
+        summary: elm_json_content['summary'],
+      )
+    end
+
+    def initialize(name, version, author, options = {})
+      @author = author
+      super(name, version, options.merge(authors: [author]))
+    end
+
+    def package_manager
+      'Elm'
+    end
+
+    def package_url
+      "https://package.elm-lang.org/packages/#{CGI.escape(author)}/#{CGI.escape(name)}/#{CGI.escape(version)}"
+    end
+  end
+end

spec/lib/license_finder/packages/elm_package_spec.rb

@@ -0,0 +1,33 @@
+require 'spec_helper'
+
+module LicenseFinder
+  describe ElmPackage do
+    let(:spec) do
+      {
+        "type": "package",
+        "name": "elm/time",
+        "summary": "Work with POSIX times, time zones, years, months, days, hours, seconds, etc.",
+        "license": "BSD-3-Clause",
+        "version": "1.0.0",
+        "exposed-modules": [
+          "Time"
+        ],
+        "elm-version": "0.19.0 <= v < 0.20.0",
+        "dependencies": {
+          "elm/core": "1.0.0 <= v < 2.0.0"
+        },
+        "test-dependencies": {}
+      }.to_json
+    end
+
+    subject do
+      ElmPackage.from_elm_json("time", "1.0.0", "elm", JSON.parse(spec))
+    end
+
+    its(:authors) { is_expected.to eql ['elm'] }
+    its(:name) { is_expected.to eql 'time' }
+    its(:licenses) { is_expected.to eql 'BSD-3-Clause' }
+    its(:package_url) { is_expected.to eql "https://package.elm-lang.org/packages/elm/time/1.0.0" }
+    its(:package_manager) { 'Elm' }
+  end
+end