Merge pull request #187 from yui-knk/error_message_for_objects

Error message for objects

lib/lrama/lexer.rb

@@ -3,6 +3,7 @@
 
 module Lrama
   class Lexer
+    attr_reader :head_line, :head_column
     attr_accessor :status
     attr_accessor :end_symbol
 

parser.y

@@ -409,10 +409,18 @@ def next_token
 end
 
 def on_error(error_token_id, error_value, value_stack)
+  if error_value.respond_to?(:line) && error_value.respond_to?(:column)
+    line = error_value.line
+    first_column = error_value.column
+  else
+    line = @lexer.line
+    first_column = @lexer.head_column
+  end
+
   raise ParseError, <<~ERROR
-    #{@path}:#{@lexer.line}:#{error_value.column}: parse error on value #{error_value.inspect} (#{token_to_str(error_token_id) || '?'})
-    #{@text.split("\n")[error_value.line - 1]}
-    #{carrets(error_value)}
+    #{@path}:#{line}:#{first_column}: parse error on value #{error_value.inspect} (#{token_to_str(error_token_id) || '?'})
+    #{@text.split("\n")[line - 1]}
+    #{carrets(first_column)}
   ERROR
 end
 
@@ -433,6 +441,6 @@ def end_c_declaration
   @lexer.end_symbol = nil
 end
 
-def carrets(error_value)
-  ' ' * (error_value.column + 1) + '^' * (@lexer.column - error_value.column)
+def carrets(first_column)
+  ' ' * (first_column + 1) + '^' * (@lexer.column - first_column)
 end

spec/lrama/parser_spec.rb

@@ -1497,8 +1497,9 @@ class : keyword_class tSTRING keyword_end { code 1 }
     end
 
     describe "error messages" do
-      it "contains line number and column" do
-        y = <<~INPUT
+      context "error_value has line number and column" do
+        it "contains line number and column" do
+          y = <<~INPUT
 %{
 // Prologue
 %}
@@ -1509,12 +1510,35 @@ class : keyword_class tSTRING keyword_end { code 1 }
 
 program: /* empty */
        ;
-        INPUT
-        expect { Lrama::Parser.new(y, "error_messages/parse.y").parse }.to raise_error(<<~ERROR)
-          error_messages/parse.y:5:7: parse error on value #<struct Lrama::Lexer::Token::Ident s_value="invalid", alias_name=nil> (IDENTIFIER)
-          %expect invalid
-                  ^^^^^^^
-        ERROR
+          INPUT
+          expect { Lrama::Parser.new(y, "error_messages/parse.y").parse }.to raise_error(ParseError, <<~ERROR)
+            error_messages/parse.y:5:7: parse error on value #<struct Lrama::Lexer::Token::Ident s_value="invalid", alias_name=nil> (IDENTIFIER)
+            %expect invalid
+                    ^^^^^^^
+          ERROR
+        end
+      end
+
+      context "error_value doesn't have line number and column" do
+        it "contains line number and column" do
+          y = <<~INPUT
+%{
+// Prologue
+%}
+
+%expect 0 10
+
+%%
+
+program: /* empty */
+       ;
+          INPUT
+          expect { Lrama::Parser.new(y, "error_messages/parse.y").parse }.to raise_error(ParseError, <<~ERROR)
+            error_messages/parse.y:5:9: parse error on value 10 (INTEGER)
+            %expect 0 10
+                      ^^
+          ERROR
+        end
       end
     end
   end