From d9cb8c8c5e68e8156daf064d25847054ddb4a32c Mon Sep 17 00:00:00 2001
From: Alex Beregszaszi <alex@rtfs.hu>
Date: Fri, 10 Jul 2020 16:05:52 +0100
Subject: [PATCH] Add ScannerKind and replace supportPeriodInIdentifier

---
 liblangutil/Scanner.cpp              | 10 ++--------
 liblangutil/Scanner.h                | 21 ++++++++++++++++-----
 libyul/AsmParser.cpp                 |  4 ++--
 test/libsolidity/SolidityScanner.cpp |  6 +++---
 4 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/liblangutil/Scanner.cpp b/liblangutil/Scanner.cpp
index 3e125f04e..017a65e18 100644
--- a/liblangutil/Scanner.cpp
+++ b/liblangutil/Scanner.cpp
@@ -147,7 +147,7 @@ void Scanner::reset(shared_ptr<CharStream> _source)
 void Scanner::reset()
 {
 	m_source->reset();
-	m_supportPeriodInIdentifier = false;
+	m_kind = ScannerKind::Solidity;
 	m_char = m_source->get();
 	skipWhitespace();
 	next();
@@ -163,12 +163,6 @@ void Scanner::setPosition(size_t _offset)
 	next();
 }
 
-void Scanner::supportPeriodInIdentifier(bool _value)
-{
-	m_supportPeriodInIdentifier = _value;
-	rescan();
-}
-
 bool Scanner::scanHexByte(char& o_scannedByte)
 {
 	char x = 0;
@@ -970,7 +964,7 @@ tuple<Token, unsigned, unsigned> Scanner::scanIdentifierOrKeyword()
 	LiteralScope literal(this, LITERAL_TYPE_STRING);
 	addLiteralCharAndAdvance();
 	// Scan the rest of the identifier characters.
-	while (isIdentifierPart(m_char) || (m_char == '.' && m_supportPeriodInIdentifier))
+	while (isIdentifierPart(m_char) || (m_char == '.' && m_kind == ScannerKind::Yul))
 		addLiteralCharAndAdvance();
 	literal.complete();
 	return TokenTraits::fromIdentifierOrKeyword(m_tokens[NextNext].literal);
diff --git a/liblangutil/Scanner.h b/liblangutil/Scanner.h
index 24ec098ab..f44a9940a 100644
--- a/liblangutil/Scanner.h
+++ b/liblangutil/Scanner.h
@@ -68,6 +68,12 @@ class AstRawString;
 class AstValueFactory;
 class ParserRecorder;
 
+enum class ScannerKind
+{
+	Solidity,
+	Yul
+};
+
 enum class ScannerError
 {
 	NoError,
@@ -107,9 +113,14 @@ public:
 	/// Resets scanner to the start of input.
 	void reset();
 
-	/// Enables or disables support for period in identifier.
-	/// This re-scans the current token and comment literal and thus invalidates it.
-	void supportPeriodInIdentifier(bool _value);
+	/// Changes the scanner mode.
+	void setScannerMode(ScannerKind _kind)
+	{
+		m_kind = _kind;
+
+		// Invalidate lookahead buffer.
+		rescan();
+	}
 
 	/// @returns the next token and advances input
 	Token next();
@@ -249,8 +260,6 @@ private:
 	size_t sourcePos() const { return m_source->position(); }
 	bool isSourcePastEndOfInput() const { return m_source->isPastEndOfInput(); }
 
-	bool m_supportPeriodInIdentifier = false;
-
 	enum TokenIndex { Current, Next, NextNext };
 
 	TokenDesc m_skippedComments[3] = {}; // desc for the current, next and nextnext skipped comment
@@ -258,6 +267,8 @@ private:
 
 	std::shared_ptr<CharStream> m_source;
 
+	ScannerKind m_kind = ScannerKind::Solidity;
+
 	/// one character look-ahead, equals 0 at end of input
 	char m_char;
 };
diff --git a/libyul/AsmParser.cpp b/libyul/AsmParser.cpp
index 6c5d97e36..5dd0d854e 100644
--- a/libyul/AsmParser.cpp
+++ b/libyul/AsmParser.cpp
@@ -42,8 +42,8 @@ unique_ptr<Block> Parser::parse(std::shared_ptr<Scanner> const& _scanner, bool _
 {
 	m_recursionDepth = 0;
 
-	_scanner->supportPeriodInIdentifier(true);
-	ScopeGuard resetScanner([&]{ _scanner->supportPeriodInIdentifier(false); });
+	_scanner->setScannerMode(ScannerKind::Yul);
+	ScopeGuard resetScanner([&]{ _scanner->setScannerMode(ScannerKind::Solidity); });
 
 	try
 	{
diff --git a/test/libsolidity/SolidityScanner.cpp b/test/libsolidity/SolidityScanner.cpp
index 8f2e6ed59..381e8e318 100644
--- a/test/libsolidity/SolidityScanner.cpp
+++ b/test/libsolidity/SolidityScanner.cpp
@@ -214,7 +214,7 @@ BOOST_AUTO_TEST_CASE(leading_dot_in_identifier)
 	BOOST_CHECK_EQUAL(scanner.next(), Token::LParen);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::EOS);
 	scanner.reset(CharStream("function .a(", ""));
-	scanner.supportPeriodInIdentifier(true);
+	scanner.setScannerMode(ScannerKind::Yul);
 	BOOST_CHECK_EQUAL(scanner.currentToken(), Token::Function);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::Period);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::Identifier);
@@ -233,7 +233,7 @@ BOOST_AUTO_TEST_CASE(middle_dot_in_identifier)
 	BOOST_CHECK_EQUAL(scanner.next(), Token::LParen);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::EOS);
 	scanner.reset(CharStream("function a...a(", ""));
-	scanner.supportPeriodInIdentifier(true);
+	scanner.setScannerMode(ScannerKind::Yul);
 	BOOST_CHECK_EQUAL(scanner.currentToken(), Token::Function);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::Identifier);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::LParen);
@@ -249,7 +249,7 @@ BOOST_AUTO_TEST_CASE(trailing_dot_in_identifier)
 	BOOST_CHECK_EQUAL(scanner.next(), Token::LParen);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::EOS);
 	scanner.reset(CharStream("function a.(", ""));
-	scanner.supportPeriodInIdentifier(true);
+	scanner.setScannerMode(ScannerKind::Yul);
 	BOOST_CHECK_EQUAL(scanner.currentToken(), Token::Function);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::Identifier);
 	BOOST_CHECK_EQUAL(scanner.next(), Token::LParen);