Merge pull request #4684 from ethereum/underscores_in_numeric_literals

[BREAKING] Underscores in numeric literals

2 files changed, 43 insertions, 0 deletions

diff --git a/libsolidity/analysis/SyntaxChecker.cpp b/libsolidity/analysis/SyntaxChecker.cpp
index 77492499..ac4fa72b 100644
--- a/libsolidity/analysis/SyntaxChecker.cpp
+++ b/libsolidity/analysis/SyntaxChecker.cpp
@@ -24,6 +24,9 @@
 #include <libsolidity/interface/Version.h>
 #include <boost/algorithm/cxx11/all_of.hpp>
 
+#include <boost/algorithm/string.hpp>
+#include <string>
+
 using namespace std;
 using namespace dev;
 using namespace dev::solidity;
@@ -183,6 +186,45 @@ bool SyntaxChecker::visit(Throw const& _throwStatement)
 	return true;
 }
 
+bool SyntaxChecker::visit(Literal const& _literal)
+{
+	if (_literal.token() != Token::Number)
+		return true;
+
+	ASTString const& value = _literal.value();
+	solAssert(!value.empty(), "");
+
+	// Generic checks no matter what base this number literal is of:
+	if (value.back() == '_')
+	{
+		m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No trailing underscores allowed.");
+		return true;
+	}
+
+	if (value.find("__") != ASTString::npos)
+	{
+		m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. Only one consecutive underscores between digits allowed.");
+		return true;
+	}
+
+	if (!_literal.isHexNumber()) // decimal literal
+	{
+		if (value.find("._") != ASTString::npos)
+			m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No underscores in front of the fraction part allowed.");
+
+		if (value.find("_.") != ASTString::npos)
+			m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No underscores in front of the fraction part allowed.");
+
+		if (value.find("_e") != ASTString::npos)
+			m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No underscore at the end of the mantissa allowed.");
+
+		if (value.find("e_") != ASTString::npos)
+			m_errorReporter.syntaxError(_literal.location(), "Invalid use of underscores in number literal. No underscore in front of exponent allowed.");
+	}
+
+	return true;
+}
+
 bool SyntaxChecker::visit(UnaryOperation const& _operation)
 {
 	if (_operation.getOperator() == Token::Add)
diff --git a/libsolidity/analysis/SyntaxChecker.h b/libsolidity/analysis/SyntaxChecker.h
index 28a0f66e..897df676 100644
--- a/libsolidity/analysis/SyntaxChecker.h
+++ b/libsolidity/analysis/SyntaxChecker.h
@@ -73,6 +73,7 @@ private:
 	virtual bool visit(VariableDeclarationStatement const& _statement) override;
 
 	virtual bool visit(StructDefinition const& _struct) override;
+	virtual bool visit(Literal const& _literal) override;
 
 	ErrorReporter& m_errorReporter;