@@ -1,7 +1,7 @@ module TireSwing class ParseError < StandardError attr_reader :parser - def initialize(message, parser) + def initialize(message, parser=nil) @parser = parser super(message) end lib/tire_swing/error.rb @@ -15,12 +15,9 @@ module TireSwing attribs.each do |attrib| case attrib when Symbol, String - attribute(attrib.to_s) { raise "no value given for #{attrib}" } + add_mapping(attrib, attrib) when Hash - attrib.each do |name, symbol| - attribute(name.to_s) { raise "no value given for #{name}" } - attribute_mapping[name.to_s] = symbol - end + attrib.each { |name, symbol| add_mapping(name, symbol) } end end end @@ -31,6 +28,12 @@ module TireSwing @attribute_mapping ||= {} end + def self.add_mapping(name, value) + attribute(name.to_s) { raise "no value given for #{name}" } + attribute_mapping[name.to_s] = value + end + + # keep track of where this node lives in the tree attr_accessor :parent # Instantiate a node. @@ -56,13 +59,9 @@ module TireSwing protected # Auto-builds this node using the provided parsed node and the defined attributes and mapped attributes. - def build_from_parsed_node(parsed_node) + def build_from_parsed_node(node) attributes.each do |attrib| - if handler = mapping(attrib) - value = apply_mapping(handler, parsed_node) - else - value = parsed_node.send(attrib) - end + value = apply_mapping(attrib, node) value = if value.kind_of?(Array) value.map { |val| extract_value(val) } @@ -74,18 +73,28 @@ module TireSwing end end - def apply_mapping(handler, parsed_node) - # TODO add in handler for arrays of methods to call in order + def apply_mapping(attrib, node) + handler = mapping_for(attrib) + if handler.kind_of?(Proc) - value = handler.call(parsed_node) + value = handler.call(node) else - # TODO need to add more error checking - if parsed_node.respond_to?(handler) - value = parsed_node.send(handler) - else - value = parsed_node.text_value.send(handler) - end + send_handler_method handler, node + end + + end + + def send_handler_method(handler, node) + if node.respond_to?(handler) + value = node.send(handler) + else + value = node.text_value.send(handler) end + rescue NoMethodError + context = node.text_value.split("\n") + context = context.size > 1 ? context.first + "..." : context + raise ParseError, + %Q{expected node containing "#{context}" or its text value to respond to #{handler.inspect}} end def extract_value(value) @@ -104,7 +113,7 @@ module TireSwing self.class.attributes end - def mapping(name) + def mapping_for(name) self.class.attribute_mapping[name] end lib/tire_swing/node.rb @@ -6,6 +6,14 @@ describe TireSwing::ParseError do it "takes a message and a parser instance" do TireSwing::ParseError.new("message", "parser").should be_an_instance_of(TireSwing::ParseError) end + + it "does not require a parser instance" do + TireSwing::ParseError.new("message").message.should == "message" + end + end + + it "is a subclass of StandardError" do + TireSwing::ParseError.new("message", "parser").should be_a_kind_of(StandardError) end it "has a message" do spec/error_spec.rb @@ -48,11 +48,6 @@ describe TireSwing::Node do n = @node.new lambda { n.lhs }.should raise_error(RuntimeError, "no value given for lhs") end - - it "returns a class with an attribute mapping" do - @node.attribute_mapping.should == {"lhs" => :left_value, "rhs" => :right_value} - end - end describe "with a mix of named attributes and hash attributes" do @@ -63,11 +58,6 @@ describe TireSwing::Node do it "creates a class with attributes matching the named attributes and hash keys" do @node.attributes.should == %w(one two three) end - - it "updates the attribute mapping" do - @node.attribute_mapping.should == {"three" => :value} - end - end end @@ -153,6 +143,28 @@ describe TireSwing::Node do end end + describe "for a node lacking the required named attribute" do + it "raises a parse exception including the text value of the node" do + node = TireSwing::Node.create :foo + @top.should_receive(:foo).and_raise(NoMethodError.new("undefined method `foo'...")) + @top.stub!(:text_value).and_return("value") + lambda do + node.new(@top) + end.should raise_error(TireSwing::ParseError, /expected.*"value".*foo/) + end + end + + describe "for a node lacking the defined method for a name/method mapping" do + it "raises an exception including the text value of the node" do + node = TireSwing::Node.create :foo => :bar + @top.should_receive(:bar).and_raise(NoMethodError.new("undefined method `bar'...")) + @top.stub!(:text_value).and_return("value") + lambda do + node.new(@top) + end.should raise_error(TireSwing::ParseError, /expected.*"value".*bar/) + end + end + end end spec/node_spec.rb @@ -70,7 +70,7 @@ end describe "with invalid input" do - it "raises an exception with" do + it "raises an exception with the parsing error" do lambda { parse }.should raise_error(TireSwing::ParseError, /as3f.*\^/m) end spec/parser_extension_spec.rb 4338421e276a054e8d174cd9ac0093230d29b4a8 Nathan Witmer nwitmer@gmail.com http://github.com/aniero/tire_swing/commit/a223d5c935133db673a11e5115588f05145d60d9 a223d5c935133db673a11e5115588f05145d60d9 2008-12-05T16:40:05-08:00 2008-12-05T16:20:19-08:00 Added error handling for NoMethodErrors when building the AST 097c2eb7d1ddb59eefe09f569eba169579209c5b Nathan Witmer nwitmer@gmail.com