Move pipeline expression lexemes to a separate module

lib/gitlab/ci/pipeline/expression/equals.rb

-module Gitlab
-  module Ci
-    module Pipeline
-      module Expression
-        class Equals < Expression::Lexeme
-          PATTERN = /==/.freeze
-          TYPE = :operator
-
-          def initialize(left, right)
-            @left = left
-            @right = right
-          end
-
-          def evaluate(**variables)
-            @left.evaluate(variables) == @right.evaluate(variables)
-          end
-
-          def self.build(value, behind, ahead)
-            new(behind, ahead)
-          end
-        end
-      end
-    end
-  end
-end

lib/gitlab/ci/pipeline/expression/lexeme.rb

-module Gitlab
-  module Ci
-    module Pipeline
-      module Expression
-        class Lexeme
-          def evaluate(**variables)
-            raise NotImplementedError
-          end
-
-          def self.build(token)
-            raise NotImplementedError
-          end
-
-          def self.type
-            self::TYPE
-          end
-
-          def self.scan(scanner)
-            if scanner.scan(self::PATTERN)
-              Expression::Token.new(scanner.matched, self)
-            end
-          end
-        end
-      end
-    end
-  end
-end

lib/gitlab/ci/pipeline/expression/lexeme/base.rb

+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        module Lexeme
+          class Base
+            def evaluate(**variables)
+              raise NotImplementedError
+            end
+
+            def self.build(token)
+              raise NotImplementedError
+            end
+
+            def self.type
+              self::TYPE
+            end
+
+            def self.scan(scanner)
+              if scanner.scan(self::PATTERN)
+                Expression::Token.new(scanner.matched, self)
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/pipeline/expression/lexeme/equals.rb

+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        module Lexeme
+          class Equals < Lexeme::Base
+            PATTERN = /==/.freeze
+            TYPE = :operator
+
+            def initialize(left, right)
+              @left = left
+              @right = right
+            end
+
+            def evaluate(**variables)
+              @left.evaluate(variables) == @right.evaluate(variables)
+            end
+
+            def self.build(_value, behind, ahead)
+              new(behind, ahead)
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/pipeline/expression/null.rb → lib/gitlab/ci/pipeline/expression/lexeme/null.rb

@@ -2,7 +2,8 @@ module Gitlab
   module Ci
     module Pipeline
       module Expression
-        class Null < Expression::Lexeme
+        module Lexeme
+          class Null < Lexeme::Base
             PATTERN = /null/.freeze
             TYPE = :value
 
@@ -17,4 +18,5 @@ module Gitlab
         end
       end
     end
+  end
 end

lib/gitlab/ci/pipeline/expression/lexeme/string.rb

+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        module Lexeme
+          class String < Lexeme::Base
+            PATTERN = /"(?<string>.+?)"/.freeze
+            TYPE = :value
+
+            def initialize(value)
+              @value = value
+            end
+
+            def evaluate(**_)
+              @value.to_s
+            end
+
+            def self.build(string)
+              new(string.match(PATTERN)[:string])
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/pipeline/expression/lexeme/variable.rb

+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        module Lexeme
+          class Variable < Lexeme::Base
+            PATTERN = /\$(?<name>\w+)/.freeze
+            TYPE = :value
+
+            def initialize(name)
+              @name = name
+            end
+
+            def evaluate(**variables)
+            end
+
+            def self.build(string)
+              new(string.match(PATTERN)[:name])
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/pipeline/expression/lexer.rb

@@ -4,9 +4,9 @@ module Gitlab
       module Expression
         class Lexer
           LEXEMES = [
-            Expression::Variable,
-            Expression::String,
-            Expression::Equals
+            Expression::Lexeme::Variable,
+            Expression::Lexeme::String,
+            Expression::Lexeme::Equals
           ].freeze
 
           MAX_CYCLES = 5

lib/gitlab/ci/pipeline/expression/parser.rb

@@ -22,7 +22,7 @@ module Gitlab
               end
             end
           rescue StopIteration
-            @nodes.last || Expression::Null.new
+            @nodes.last || Expression::Lexeme::Null.new
           end
 
           def self.seed(statement)

lib/gitlab/ci/pipeline/expression/string.rb

-module Gitlab
-  module Ci
-    module Pipeline
-      module Expression
-        class String < Expression::Lexeme
-          PATTERN = /"(?<string>.+?)"/.freeze
-          TYPE = :value
-
-          def initialize(value)
-            @value = value
-          end
-
-          def evaluate(**_)
-            @value.to_s
-          end
-
-          def self.build(string)
-            new(string.match(PATTERN)[:string])
-          end
-        end
-      end
-    end
-  end
-end

lib/gitlab/ci/pipeline/expression/variable.rb

-module Gitlab
-  module Ci
-    module Pipeline
-      module Expression
-        class Variable < Expression::Lexeme
-          PATTERN = /\$(?<name>\w+)/.freeze
-          TYPE = :value
-
-          def initialize(name)
-            @name = name
-          end
-
-          def evaluate(**variables)
-          end
-
-          def self.build(string)
-            new(string.match(PATTERN)[:name])
-          end
-        end
-      end
-    end
-  end
-end

spec/lib/gitlab/ci/pipeline/expression/parser_spec.rb

@@ -5,21 +5,21 @@ describe Gitlab::Ci::Pipeline::Expression::Parser do
     context 'when using operators' do
       it 'returns a reverse descent parse tree' do
         expect(described_class.seed('$VAR1 == "123" == $VAR2').tree)
-          .to be_a Gitlab::Ci::Pipeline::Expression::Equals
+          .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Equals
       end
     end
 
     context 'when using a single token' do
       it 'returns a single token instance' do
         expect(described_class.seed('$VAR').tree)
-          .to be_a Gitlab::Ci::Pipeline::Expression::Variable
+          .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Variable
       end
     end
 
     context 'when expression is empty' do
       it 'returns a null token' do
         expect(described_class.seed('').tree)
-          .to be_a Gitlab::Ci::Pipeline::Expression::Null
+          .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Null
       end
     end
   end

spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb

@@ -37,7 +37,7 @@ describe Gitlab::Ci::Pipeline::Expression::Statement do
 
         it 'returns a reverse descent parse tree' do
           expect(subject.parse_tree)
-            .to be_a Gitlab::Ci::Pipeline::Expression::Equals
+            .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Equals
         end
       end
 
@@ -46,7 +46,7 @@ describe Gitlab::Ci::Pipeline::Expression::Statement do
 
         it 'returns a single token instance' do
           expect(subject.parse_tree)
-            .to be_a Gitlab::Ci::Pipeline::Expression::Variable
+            .to be_a Gitlab::Ci::Pipeline::Expression::Lexeme::Variable
         end
       end
     end