From a59546473916fcccb2ddc444e7264a94c551c617 Mon Sep 17 00:00:00 2001
From: Lefteris Karapetsas <lefteris@refu.co>
Date: Sun, 30 Nov 2014 22:43:40 +0100
Subject: [PATCH] Simplifying scanning for natspec documentation

- Scanner no longer remembers the last natspect comment until
  a new one is encountered. It remembers it only until the next
  scan()
---
 Parser.cpp  |  4 +---
 Scanner.cpp | 44 +++++++++++++++-----------------------------
 Scanner.h   |  8 +++-----
 3 files changed, 19 insertions(+), 37 deletions(-)

diff --git a/Parser.cpp b/Parser.cpp
index 9ed081cce..0506bc3e3 100644
--- a/Parser.cpp
+++ b/Parser.cpp
@@ -119,10 +119,8 @@ ASTPointer<FunctionDefinition> Parser::parseFunctionDefinition(bool _isPublic)
 	ASTNodeFactory nodeFactory(*this);
 	ASTPointer<ASTString> docstring;
 	if (m_scanner->getCurrentCommentLiteral() != "")
-	{
 		docstring = std::make_shared<ASTString>(m_scanner->getCurrentCommentLiteral());
-		m_scanner->clearCurrentCommentLiteral();
-	}
+
 	expectToken(Token::FUNCTION);
 	ASTPointer<ASTString> name(expectIdentifierToken());
 	ASTPointer<ParameterList> parameters(parseParameterList());
diff --git a/Scanner.cpp b/Scanner.cpp
index 4da9874a2..3335e9df4 100644
--- a/Scanner.cpp
+++ b/Scanner.cpp
@@ -104,16 +104,14 @@ int hexValue(char c)
 
 void Scanner::reset(CharStream const& _source)
 {
-	bool foundDocComment;
 	m_source = _source;
 	m_char = m_source.get();
 	skipWhitespace();
-	foundDocComment = scanToken();
+	scanToken();
 
-	// special version of Scanner:next() taking the previous scanToken() result into account
 	m_currentToken = m_nextToken;
-	if (scanToken() || foundDocComment)
-		m_skippedComment = m_nextSkippedComment;
+	m_skippedComment = m_nextSkippedComment;
+	scanToken();
 }
 
 
@@ -142,8 +140,9 @@ BOOST_STATIC_ASSERT(Token::NUM_TOKENS <= 0x100);
 Token::Value Scanner::next()
 {
 	m_currentToken = m_nextToken;
-	if (scanToken())
-		m_skippedComment = m_nextSkippedComment;
+	m_skippedComment = m_nextSkippedComment;
+	scanToken();
+
 	return m_currentToken.token;
 }
 
@@ -188,13 +187,13 @@ Token::Value Scanner::scanDocumentationComment()
 		{
 			// check if next line is also a documentation comment
 			skipWhitespace();
-			if (m_source.get(0) == '/' &&
+			if (!m_source.isPastEndOfInput(3) &&
+				m_source.get(0) == '/' &&
 				m_source.get(1) == '/' &&
-				m_source.get(2) == '/' &&
-				!m_source.isPastEndOfInput(3))
+				m_source.get(2) == '/')
 			{
 				addCommentLiteralChar('\n');
-				m_char = m_source.advanceBy(3);
+				m_char = m_source.advanceAndGet(3);
 			}
 			else
 				break; // next line is not a documentation comment, we are done
@@ -230,10 +229,10 @@ Token::Value Scanner::skipMultiLineComment()
 	return Token::ILLEGAL;
 }
 
-bool Scanner::scanToken()
+void Scanner::scanToken()
 {
-	bool foundDocComment = false;
 	m_nextToken.literal.clear();
+	m_nextSkippedComment.literal.clear();
 	Token::Value token;
 	do
 	{
@@ -345,7 +344,6 @@ bool Scanner::scanToken()
 					m_nextSkippedComment.location.end = getSourcePos();
 					m_nextSkippedComment.token = comment;
 					token = Token::WHITESPACE;
-					foundDocComment = true;
 				}
 				else
 					token = skipSingleLineComment();
@@ -441,8 +439,6 @@ bool Scanner::scanToken()
 	while (token == Token::WHITESPACE);
 	m_nextToken.location.end = getSourcePos();
 	m_nextToken.token = token;
-
-	return foundDocComment;
 }
 
 bool Scanner::scanEscape()
@@ -783,23 +779,13 @@ Token::Value Scanner::scanIdentifierOrKeyword()
 	return KeywordOrIdentifierToken(m_nextToken.literal);
 }
 
-char CharStream::advanceAndGet()
+char CharStream::advanceAndGet(size_t _chars)
 {
 	if (isPastEndOfInput())
 		return 0;
-	++m_pos;
-	if (isPastEndOfInput())
-		return 0;
-	return get();
-}
-
-char CharStream::advanceBy(size_t _chars)
-{
-	if (asserts(!isPastEndOfInput(_chars)))
-		BOOST_THROW_EXCEPTION(InternalCompilerError());
-
 	m_pos += _chars;
-
+	if (isPastEndOfInput())
+		return 0;
 	return m_source[m_pos];
 }
 
diff --git a/Scanner.h b/Scanner.h
index 702310102..e9262ba39 100644
--- a/Scanner.h
+++ b/Scanner.h
@@ -76,8 +76,7 @@ public:
 	int getPos() const { return m_pos; }
 	bool isPastEndOfInput(size_t _charsForward = 0) const { return (m_pos + _charsForward) >= m_source.size(); }
 	char get(size_t _charsForward = 0) const { return m_source[m_pos + _charsForward]; }
-	char advanceAndGet();
-	char advanceBy(size_t _chars);
+	char advanceAndGet(size_t _chars=1);
 	char rollback(size_t _amount);
 
 	///@{
@@ -213,9 +212,8 @@ private:
 
 	bool scanHexByte(char& o_scannedByte);
 
-	/// Scans a single Solidity token. Returns true if the scanned token was
-	/// a skipped documentation comment. False in all other cases.
-	bool scanToken();
+	/// Scans a single Solidity token.
+	void scanToken();
 
 	/// Skips all whitespace and @returns true if something was skipped.
 	bool skipWhitespace();