Parse application

lib/chervil/ast.rb

@@ -1,4 +1,5 @@
 module Chervil::AST
+  require "chervil/ast/application"
   require "chervil/ast/identifier"
   require "chervil/ast/number"
 end

lib/chervil/ast/application.rb

@@ -0,0 +1,15 @@
+module Chervil::AST
+  class Application
+    attr_reader :expr
+    attr_reader :arguments
+
+    def initialize(expr, arguments)
+      @expr = expr
+      @arguments = arguments
+    end
+
+    def ==(other)
+      @expr == other.expr && @arguments == other.arguments
+    end
+  end
+end

lib/chervil/lexer.rb

@@ -23,11 +23,13 @@ module Chervil
       when ')'
         advance
         Token.new(:rparen, ")")
-      when ' '
-        advance
-        nil
       else
         source = @source.slice(@position..-1)
+        while source.match(/^\s/)
+          advance
+          source = @source.slice(@position..-1)
+        end
+
         if match = source.match(/^[0-9]+(\.[0-9]+)?/)
           advance(match[0].size)
           Token.new(:number, match[0])
@@ -42,7 +44,6 @@ module Chervil
       tokens = Array.new
       loop do
         token = get_next_token
-        next if token.nil?
         tokens << token
         break if token.type == :eof
       end

lib/chervil/parser.rb

@@ -18,9 +18,25 @@ module Chervil
         constant
       elsif @current_token.type == :identifier
         identifier
+      elsif @current_token.type == :lparen
+        application
       end
     end
 
+    def application
+      eat(:lparen)
+      expression = expr
+
+      args = Array.new
+      until @current_token.type == :rparen
+        args << expr
+      end
+
+      eat(:rparen)
+
+      AST::Application.new(expression, args)
+    end
+
     def identifier
       identifier = eat(:identifier)
       AST::Identifier.new(identifier.value)

spec/parser_spec.rb

@@ -13,5 +13,14 @@ module Chervil
     it 'parses an identifier' do
       expect(parse('+').first).to eq(AST::Identifier.new('+'))
     end
+
+    it 'parses an application' do
+      expect(parse('(+ 1 2)').first).to eq(
+        AST::Application.new(
+          AST::Identifier.new('+'),
+          [AST::Number.new(1.0), AST::Number.new(2.0)]
+        )
+      )
+    end
   end
 end