//while-condition -> expression declaration
ExpressionPtr Parser::parseConditionExpression()
{
Token token;
expect_next(token);
if(token.type == TokenType::Identifier && token.identifier.keyword != Keyword::_)
{
Keyword::T keyword = token.identifier.keyword;
tassert(token, keyword == Keyword::Var || keyword == Keyword::Let, Errors::E_EXPECTED_EXPRESSION_VAR_OR_LET_IN_A_CONDITION_1, L"if");
ValueBindingPatternPtr value = nodeFactory->createValueBindingPattern(token.state);
value->setReadOnly(keyword == Keyword::Let);
PatternPtr binding = parsePattern();
value->setBinding(binding);
if(binding->getNodeType() == NodeType::TypedPattern)
{
TypedPatternPtr tpattern = std::static_pointer_cast<TypedPattern>(binding);
value->setBinding(tpattern->getPattern());
value->setDeclaredType(tpattern->getDeclaredType());
}
if (!match(L"=", token))
{
tassert(token, false, Errors::E_VARIABLE_BINDING_IN_A_CONDITION_REQUIRES_AN_INITIALIZER);
}
AssignmentPtr assignment = nodeFactory->createAssignment(token.state);
ExpressionPtr expr = parseExpression();
assignment->setLHS(value);
assignment->setRHS(expr);
return assignment;
}
else
{
restore(token);
return parseExpression();
}
}
/*
GRAMMAR OF A CONSTANT DECLARATION
constant-declaration → attributes opt declaration-specifiers opt let pattern-initializer-list
pattern-initializer-list → pattern-initializer | pattern-initializer,pattern-initializer-list
pattern-initializer → pattern initializer opt
initializer → =expression
*/
DeclarationPtr Parser::parseLet(const std::vector<AttributePtr>& attrs, int specifiers)
{
Token token;
Flags flag(this, UNDER_LET);
expect(Keyword::Let, token);
ValueBindingsPtr ret = nodeFactory->createValueBindings(token.state);
ret->setReadOnly(true);
ret->setAttributes(attrs);
ret->setSpecifiers(specifiers);
do
{
PatternPtr pattern = parsePattern();
ExpressionPtr initializer = NULL;
if(match(L"="))
{
initializer = parseExpression();
}
ValueBindingPtr constant = nodeFactory->createValueBinding(*pattern->getSourceInfo());
constant->setAttributes(attrs);
constant->setSpecifiers(specifiers);
constant->setName(pattern);
TypedPatternPtr typedPattern = std::dynamic_pointer_cast<TypedPattern>(pattern);
if(typedPattern)
{
//promote typed pattern
constant->setDeclaredType(typedPattern->getDeclaredType());
constant->setName(typedPattern->getPattern());
}
constant->setInitializer(initializer);
ret->add(constant);
}while(match(L","));
return ret;
}
/*
GRAMMAR OF A PATTERN
pattern → wildcard-pattern type-annotation opt
pattern → identifier-pattern type-annotation opt
pattern → value-binding-pattern
pattern → tuple-pattern type-annotation opt
pattern → enum-case-pattern
pattern → type-casting-pattern
pattern → expression-pattern
*/
PatternPtr Parser::parsePattern()
{
Token token;
expect_next(token);
if(token.type == TokenType::Identifier)
{
switch(token.identifier.keyword)
{
// pattern → wildcard-pattern type-annotationopt
// pattern → identifier-pattern type-annotationopt
case Keyword::_:
{
IdentifierPtr id = nodeFactory->createIdentifier(token.state);
id->setIdentifier(token.token);
if((flags & UNDER_CASE) == 0)//type annotation is not parsed when it's inside a let/var
{
if(match(L":"))
{
TypedPatternPtr ret = nodeFactory->createTypedPattern(*id->getSourceInfo());
TypeNodePtr type = parseTypeAnnotation();
ret->setDeclaredType(type);
ret->setPattern(id);
return ret;
}
}
return id;
}
// pattern → value-binding-pattern
case Keyword::Var:
case Keyword::Let:
{
ValueBindingPatternPtr ret = nodeFactory->createValueBindingPattern(token.state);
PatternPtr binding = parsePattern();
if(TypedPatternPtr p = std::dynamic_pointer_cast<TypedPattern>(binding))
{
ret->setBinding(p->getPattern());
ret->setDeclaredType(p->getDeclaredType());
}
else
{
ret->setBinding(binding);
}
ret->setReadOnly(token.identifier.keyword == Keyword::Let);
return ret;
}
default:
break;
}
}
restore(token);
if(token.type == TokenType::OpenParen)
{
//pattern → tuple-pattern type-annotation opt
TuplePtr ret = std::static_pointer_cast<Tuple>(parseTuple());
if(flags & (UNDER_LET | UNDER_VAR))
{
//type-annotation only exists under let/var statement
if(match(L":"))
{
TypeNodePtr type = parseTypeAnnotation();
TypedPatternPtr pattern = nodeFactory->createTypedPattern(*ret->getSourceInfo());
pattern->setDeclaredType(type);
pattern->setPattern(ret);
return pattern;
}
}
return ret;
}
if(this->flags & UNDER_SWITCH_CASE)
{
//the following patterns are only exists in switch/case statement
// pattern → enum-case-pattern
if(token.type == TokenType::Attribute || token == L".")
{
return parseEnumPattern();
}
// pattern → type-casting-pattern
if(token.getKeyword() == Keyword::Is)
{
return parseTypeCastingPattern();
}
}
// pattern → expression-pattern
PatternPtr ret = parseExpression();
if(this->flags & UNDER_SWITCH_CASE)
{
if(predicate(L"as"))
{
restore(token);
ret = NULL;
return parseTypeCastingPattern();
}
}
return ret;
}
void NodeVisitor::visitTypedPattern(const TypedPatternPtr& node)
{
ACCEPT(node->getPattern());
}
void SemanticAnalyzer::validateTupleTypeDeclaration(const PatternPtr& name, const TypePtr& declType, const TypePtr& initType)
{
switch(name->getNodeType())
{
case NodeType::Identifier:
{
if(initType && declType && !initType->canAssignTo(declType))
{
error(name, Errors::E_CANNOT_CONVERT_EXPRESSION_TYPE_2, initType->toString(), declType->toString());
}
break;
}
case NodeType::TypedPattern:
{
TypedPatternPtr pat = static_pointer_cast<TypedPattern>(name);
assert(pat->getDeclaredType());
TypePtr nameType = lookupType(pat->getDeclaredType());
assert(nameType != nullptr);
if(declType && !Type::equals(nameType, declType))
{
error(name, Errors::E_TYPE_ANNOTATION_DOES_NOT_MATCH_CONTEXTUAL_TYPE_A_1, declType->toString());
abort();
return;
}
break;
}
case NodeType::Tuple:
{
TuplePtr tuple = static_pointer_cast<Tuple>(name);
if(declType)
{
if((declType->getCategory() != Type::Tuple) || (tuple->numElements() != declType->numElementTypes()))
{
error(name, Errors::E_TYPE_ANNOTATION_DOES_NOT_MATCH_CONTEXTUAL_TYPE_A_1, declType->toString());
abort();
return;
}
}
int elements = tuple->numElements();
for(int i = 0; i < elements; i++)
{
PatternPtr element = tuple->getElement(i);
TypePtr elementDecl = declType ? declType->getElementType(i) : nullptr;
TypePtr elementInit = initType ? initType->getElementType(i) : nullptr;
validateTupleTypeDeclaration(element, elementDecl, elementInit);
}
break;
}
case NodeType::ValueBindingPattern:
break;
case NodeType::EnumCasePattern:
{
break;
}
case NodeType::TypeCase:
case NodeType::TypeCheck:
default:
error(name, Errors::E_EXPECT_TUPLE_OR_IDENTIFIER);
break;
}
}
