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Add default argument support for arrow functions (#228)
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Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu
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@rerobika @yichoi
rerobika authored and yichoi committed May 7, 2019
1 parent bc7ed2e commit d788b0b
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Showing 2 changed files with 36 additions and 103 deletions.
130 changes: 27 additions & 103 deletions src/parser/esprima_cpp/esprima.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3273,105 +3273,6 @@ class Parser : public gc {
}

// ECMA-262 12.15 Assignment Operators
void checkPatternParam(ParseParameterOptions& options, Node* param)
{
switch (param->type()) {
case Identifier:
this->validateParam(options, nullptr, ((IdentifierNode*)param)->name());
break;
/*
// case AssignmentPattern:
case AssignmentExpression:
case AssignmentExpressionBitwiseAnd:
case AssignmentExpressionBitwiseOr:
case AssignmentExpressionBitwiseXor:
case AssignmentExpressionDivision:
case AssignmentExpressionLeftShift:
case AssignmentExpressionMinus:
case AssignmentExpressionMod:
case AssignmentExpressionMultiply:
case AssignmentExpressionPlus:
case AssignmentExpressionSignedRightShift:
case AssignmentExpressionUnsignedRightShift:
case AssignmentExpressionSimple:
this->checkPatternParam(options, ((AssignmentExpressionSimpleNode*)param)->left());
break;
*/
default:
this->throwError("Arrow function default/pattern arguments are not implemented");
RELEASE_ASSERT_NOT_REACHED();
/*
case Syntax.ArrayPattern:
for (let i = 0; i < param.elements.length; i++) {
if (param.elements[i] !== null) {
this->checkPatternParam(options, param.elements[i]);
}
}
break;
case Syntax.YieldExpression:
break;
default:
RELEASE_ASSERT(param->type() == Object)
assert(param.type === Syntax.ObjectPattern, 'Invalid type');
for (let i = 0; i < param.properties.length; i++) {
this->checkPatternParam(options, param.properties[i].value);
}
break;
*/
}
}

ParseFormalParametersResult reinterpretAsCoverFormalsList(Node* expr)
{
PatternNodeVector params;
params.push_back(expr);
ParseParameterOptions options;

switch (expr->type()) {
case Identifier:
break;
case ArrowParameterPlaceHolder:
params = ((ArrowParameterPlaceHolderNode*)expr)->params();
break;
default:
return ParseFormalParametersResult();
}

for (size_t i = 0; i < params.size(); ++i) {
RefPtr<Node> param = params[i];
/*
if (param->type() == AssignmentPattern) {
if (param->right()->type() == YieldExpression) {
if (param.right.argument) {
this.throwUnexpectedToken(this.lookahead);
}
param.right.type = Syntax.Identifier;
param.right.name = 'yield';
delete param.right.argument;
delete param.right.delegate;
}
}
*/
this->checkPatternParam(options, param.get());
//params[i] = param;
}

if (this->context->strict || !this->context->allowYield) {
for (size_t i = 0; i < params.size(); ++i) {
RefPtr<Node> param = params[i];
if (param->type() == YieldExpression) {
this->throwUnexpectedToken(this->lookahead);
}
}
}

if (options.message == Messages::StrictParamDupe) {
RefPtr<Scanner::ScannerResult> token = this->context->strict ? options.stricted : options.firstRestricted;
this->throwUnexpectedToken(token, options.message);
}

return ParseFormalParametersResult(params, options.stricted, options.firstRestricted, options.message);
}

template <typename T, bool isParse>
T assignmentExpression()
Expand All @@ -3390,6 +3291,7 @@ class Parser : public gc {
RefPtr<Scanner::ScannerResult> token = startToken;
Marker lastMarker;
ASTNodeType type;
MetaNode startNode = this->createNode();

if (isParse) {
exprNode = this->conditionalExpression<Parse>();
Expand Down Expand Up @@ -3425,16 +3327,32 @@ class Parser : public gc {
exprNode = this->conditionalExpression<Parse>();
}

ParseFormalParametersResult list = this->reinterpretAsCoverFormalsList(exprNode.get()); //TODO
ParseFormalParametersResult list;
pushScopeContext(AtomicString());

if (type == Identifier) {
list = ParseFormalParametersResult();
list.params.push_back(exprNode);
list.valid = true;
} else {
this->scanner->index = startNode.index;
this->nextToken();
this->expect(LeftParenthesis);

list = this->parseFormalParameters();
scopeContexts.back()->m_paramsStart.index = startNode.index;
}

if (isParse) {
exprNode.release();
}

if (list.valid) {
if (this->hasLineTerminator) {
this->throwUnexpectedToken(this->lookahead);
}
this->context->firstCoverInitializedNameError = nullptr;

pushScopeContext(AtomicString());

extractNamesFromFunctionParams(list.params);
bool previousStrict = this->context->strict;
bool previousAllowYield = this->context->allowYield;
Expand Down Expand Up @@ -5151,6 +5069,12 @@ class Parser : public gc {
{
ASSERT(this->config.parseSingleFunction);

RefPtr<StatementContainer> argumentInitializers = nullptr;

if (this->config.reparseArguments) {
this->reparseFunctionArguments(argumentInitializers);
}

this->context->inArrowFunction = true;
if (this->match(LeftBrace)) {
return parseFunctionSourceElements();
Expand Down Expand Up @@ -5200,7 +5124,7 @@ class Parser : public gc {

this->context->inDirectCatchScope = prevInDirectCatchScope;

return this->finalize(nodeStart, new BlockStatementNode(body.get()));
return this->finalize(nodeStart, new BlockStatementNode(body.get(), argumentInitializers.get()));
}

// ECMA-262 14.1 Function Definition
Expand Down
9 changes: 9 additions & 0 deletions test/es2015/default-argument.js
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Original file line number Diff line number Diff line change
Expand Up @@ -79,3 +79,12 @@ CheckSyntaxError('function x(a =, b) {}');
CheckSyntaxError('function x(a = (b) {}');
CheckSyntaxError('function x(a, a = 5) {}');
CheckSyntaxError('function x(a = 5, a) {}');

var arrowFunc = (a = 4, b = 5, c = 6) => {
return a + b + c;
}

assert(arrowFunc() === 15);
assert(arrowFunc(1) === 12);
assert(arrowFunc(1, 2) === 9);
assert(arrowFunc(1, 2, 3) === 6);

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