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Parse multi variable declaration statement.

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This commit is contained in:
chriseth 2018-04-26 10:43:11 +02:00 committed by Alex Beregszaszi
parent 2ba0002998
commit 67d208d144
2 changed files with 76 additions and 8 deletions
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1
Changelog.md
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@ -7,6 +7,7 @@ Features:
* Control Flow Graph: Add Control Flow Graph as analysis structure.
* Control Flow Graph: Warn about returning uninitialized storage pointers.
* Gas Estimator: Only explore paths with higher gas costs. This reduces accuracy but greatly improves the speed of gas estimation.
* General: Allow multiple variables to be declared as part of a tuple assignment, e.g. ``(uint a, uint b) = ...``.
* Optimizer: Remove unnecessary masking of the result of known short instructions (``ADDRESS``, ``CALLER``, ``ORIGIN`` and ``COINBASE``).
* Parser: Display nicer error messages by showing the actual tokens and not internal names.
* Parser: Use the entire location of the token instead of only its starting position as source location for parser errors.

83
libsolidity/parsing/Parser.cpp
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@ -1086,15 +1086,79 @@ ASTPointer<Statement> Parser::parseSimpleStatement(ASTPointer<ASTString> const&
LookAheadInfo statementType;
IndexAccessedPath iap;
tie(statementType, iap) = tryParseIndexAccessedPath();
switch (statementType)
if (m_scanner->currentToken() == Token::LParen)
{
case LookAheadInfo::VariableDeclaration:
return parseVariableDeclarationStatement(_docString, typeNameFromIndexAccessStructure(iap));
case LookAheadInfo::Expression:
return parseExpressionStatement(_docString, expressionFromIndexAccessStructure(iap));
default:
solAssert(false, "");
ASTNodeFactory nodeFactory(*this);
size_t emptyComponents = 0;
// First consume all empty components.
expectToken(Token::LParen);
while (m_scanner->currentToken() == Token::Comma)
{
m_scanner->next();
emptyComponents++;
}
// Now see whether we have a variable declaration or an expression.
tie(statementType, iap) = tryParseIndexAccessedPath();
switch (statementType)
{
case LookAheadInfo::VariableDeclaration:
{
vector<ASTPointer<VariableDeclaration>> variables;
ASTPointer<Expression> value;
// We have already parsed something like `(,,,,a.b.c[2][3]`
VarDeclParserOptions options;
options.allowLocationSpecifier = true;
variables = vector<ASTPointer<VariableDeclaration>>(emptyComponents, nullptr);
variables.push_back(parseVariableDeclaration(options, typeNameFromIndexAccessStructure(iap)));
while (m_scanner->currentToken() != Token::RParen)
{
expectToken(Token::Comma);
if (m_scanner->currentToken() == Token::Comma || m_scanner->currentToken() == Token::RParen)
variables.push_back(nullptr);
else
variables.push_back(parseVariableDeclaration(options));
}
expectToken(Token::RParen);
expectToken(Token::Assign);
value = parseExpression();
nodeFactory.setEndPositionFromNode(value);
return nodeFactory.createNode<VariableDeclarationStatement>(_docString, variables, value);
}
case LookAheadInfo::Expression:
{
// Complete parsing the expression in the current component.
vector<ASTPointer<Expression>> components(emptyComponents, nullptr);
components.push_back(parseExpression(expressionFromIndexAccessStructure(iap)));
while (m_scanner->currentToken() != Token::RParen)
{
expectToken(Token::Comma);
if (m_scanner->currentToken() == Token::Comma || m_scanner->currentToken() == Token::RParen)
components.push_back(ASTPointer<Expression>());
else
components.push_back(parseExpression());
}
nodeFactory.markEndPosition();
expectToken(Token::RParen);
return parseExpressionStatement(_docString, nodeFactory.createNode<TupleExpression>(components, false));
}
default:
solAssert(false, "");
}
}
else
{
tie(statementType, iap) = tryParseIndexAccessedPath();
switch (statementType)
{
case LookAheadInfo::VariableDeclaration:
return parseVariableDeclarationStatement(_docString, typeNameFromIndexAccessStructure(iap));
case LookAheadInfo::Expression:
return parseExpressionStatement(_docString, expressionFromIndexAccessStructure(iap));
default:
solAssert(false, "");
}
}
}
@ -1144,6 +1208,9 @@ ASTPointer<VariableDeclarationStatement> Parser::parseVariableDeclarationStateme
ASTPointer<TypeName> const& _lookAheadArrayType
)
{
// This does not parse multi variable declaration statements starting directly with
// `(`, they are parsed in parseSimpleStatement, because they are hard to distinguish
// from tuple expressions.
RecursionGuard recursionGuard(*this);
ASTNodeFactory nodeFactory(*this);
if (_lookAheadArrayType)