Add base classes to evaluate variables expressions

7 files changed, 86 insertions, 2 deletions

diff --git a/lib/gitlab/ci/pipeline/expression/equality.rb b/lib/gitlab/ci/pipeline/expression/equality.rb
new file mode 100644
index 00000000000..dd2cf0118f2
--- /dev/null
+++ b/lib/gitlab/ci/pipeline/expression/equality.rb
@@ -0,0 +1,21 @@
+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        class Equality
+          PATTERN = /==/.freeze
+
+          def initialize(left, right)
+          end
+
+          def evaluate(**variables)
+            @left.evaluate(variables) == @right.evaluate(variables)
+          end
+
+          def self.build(string)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/pipeline/expression/lexer.rb b/lib/gitlab/ci/pipeline/expression/lexer.rb
new file mode 100644
index 00000000000..2734ef34c06
--- /dev/null
+++ b/lib/gitlab/ci/pipeline/expression/lexer.rb
@@ -0,0 +1,16 @@
+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        class Lexer
+          def initialize(statement)
+            @statement = statement
+          end
+
+          def tokenize
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/pipeline/expression/statement.rb b/lib/gitlab/ci/pipeline/expression/statement.rb
index adc36896fd3..e6c93288166 100644
--- a/lib/gitlab/ci/pipeline/expression/statement.rb
+++ b/lib/gitlab/ci/pipeline/expression/statement.rb
@@ -8,10 +8,10 @@ module Gitlab
             @statement = statement
           end
 
-          def errors
+          def variables
           end
 
-          def matches?
+          def evaluate
           end
         end
       end
diff --git a/lib/gitlab/ci/pipeline/expression/string.rb b/lib/gitlab/ci/pipeline/expression/string.rb
new file mode 100644
index 00000000000..6a4d78a67a1
--- /dev/null
+++ b/lib/gitlab/ci/pipeline/expression/string.rb
@@ -0,0 +1,22 @@
+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        class String
+          PATTERN = /("|')(?<value>.+)('|")/.freeze
+
+          def initialize(value)
+            @value = value
+          end
+
+          def evaluate(**_)
+            @value.to_s
+          end
+
+          def self.build(string)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/ci/pipeline/expression/variable.rb b/lib/gitlab/ci/pipeline/expression/variable.rb
new file mode 100644
index 00000000000..e547a9aaa46
--- /dev/null
+++ b/lib/gitlab/ci/pipeline/expression/variable.rb
@@ -0,0 +1,21 @@
+module Gitlab
+  module Ci
+    module Pipeline
+      module Expression
+        class Equality
+          PATTERN = /$(?<name>\w+)/.freeze
+
+          def initialize(value)
+            @value = value
+          end
+
+          def evaluate(**variables)
+          end
+
+          def self.build(string)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/ci/pipeline/expression/equality_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/equality_spec.rb
new file mode 100644
index 00000000000..e69de29bb2d
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/equality_spec.rb
diff --git a/spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb b/spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb
new file mode 100644
index 00000000000..76d0163e44b
--- /dev/null
+++ b/spec/lib/gitlab/ci/pipeline/expression/statement_spec.rb
@@ -0,0 +1,4 @@
+require 'spec_helper'
+
+describe Gitlab::Ci::Pipeline::Expression::Statement do
+end