Parse definition

lib/chervil/ast.rb

@@ -1,5 +1,6 @@
 module Chervil::AST
   require "chervil/ast/application"
+  require "chervil/ast/definition"
   require "chervil/ast/identifier"
   require "chervil/ast/number"
   require "chervil/ast/string"

lib/chervil/ast/definition.rb

@@ -0,0 +1,15 @@
+module Chervil::AST
+  class Definition
+    attr_reader :name
+    attr_reader :value
+
+    def initialize(name, value)
+      @name = name
+      @value = value
+    end
+
+    def ==(other)
+      @name == other.name && @value == other.value
+    end
+  end
+end

lib/chervil/parser.rb

@@ -24,6 +24,16 @@ module Chervil
 
     def application
       eat(:lparen)
+
+      if @current_token.type == :identifier && @current_token.value == 'define'
+        eat(:identifier)
+        name = identifier
+        value = expr
+        p @current_token
+        eat(:rparen)
+        return AST::Definition.new(name, value)
+      end
+
       expression = expr
 
       args = Array.new

spec/parser_spec.rb

@@ -26,5 +26,11 @@ module Chervil
         )
       )
     end
+
+    it 'parses a definition' do
+      expect(parse('(define x 5)').first).to eq(
+        AST::Definition.new(AST::Identifier.new('x'), AST::Number.new(5.0))
+      )
+    end
   end
 end