refactor parser, check in some failing tests

1 files changed, 20 insertions, 2 deletions

diff --git a/src/parsers.h b/src/parsers.h
index 9dc61d9..55c0eb7 100644
--- a/src/parsers.h
+++ b/src/parsers.h
@@ -48,16 +48,30 @@ struct Token {
   const char* end_;
 };
 
+/// Represents a user-understandable position within a source file.
+struct SourceLocation {
+  SourceLocation(int line, int col) : line_(line), column_(col) {}
+
+  /// Construct an error message based on the position and message,
+  /// write it into \a err, then return false.
+  bool Error(const string& message, string* err);
+
+  /// 1-based line and column numbers.
+  int line_;
+  int column_;
+};
+
 /// Processes an input stream into Tokens.
 struct Tokenizer {
   Tokenizer(bool whitespace_significant)
       : whitespace_significant_(whitespace_significant),
-        token_(Token::NONE), line_number_(1),
+        token_(Token::NONE), line_number_(0),
         last_indent_(0), cur_indent_(-1) {}
 
   void Start(const char* start, const char* end);
+  /// Report an error with a location pointing at the current token.
   bool Error(const string& message, string* err);
-  // Call Error() with "expected foo, got bar".
+  /// Call Error() with "expected foo, got bar".
   bool ErrorExpected(const string& expected, string* err);
 
   const Token& token() const { return token_; }
@@ -73,6 +87,10 @@ struct Tokenizer {
   Token::Type PeekToken();
   void ConsumeToken();
 
+  SourceLocation Location() {
+    return SourceLocation(line_number_ + 1, token_.pos_ - cur_line_ + 1);
+  }
+
   bool whitespace_significant_;
 
   const char* cur_;