// The top-level full expression recognizer.
//
// expression
// : assignment_expression COMMA assignment_expression COMMA assignment_expression ...
//
bool HlslGrammar::acceptExpression(TIntermTyped*& node)
{
// assignment_expression
if (! acceptAssignmentExpression(node))
return false;
if (! peekTokenClass(EHTokComma))
return true;
do {
// ... COMMA
TSourceLoc loc = token.loc;
advanceToken();
// ... assignment_expression
TIntermTyped* rightNode = nullptr;
if (! acceptAssignmentExpression(rightNode)) {
expected("assignment expression");
return false;
}
node = intermediate.addComma(node, rightNode, loc);
if (! peekTokenClass(EHTokComma))
return true;
} while (true);
}
// Accept a binary expression, for binary operations that
// associate left-to-right. This is, it is implicit, for example
//
// ((a op b) op c) op d
//
// binary_expression
// : expression op expression op expression ...
//
// where 'expression' is the next higher level in precedence.
//
bool HlslGrammar::acceptBinaryExpression(TIntermTyped*& node, PrecedenceLevel precedenceLevel)
{
if (precedenceLevel > PlMul)
return acceptUnaryExpression(node);
// assignment_expression
if (! acceptBinaryExpression(node, (PrecedenceLevel)(precedenceLevel + 1)))
return false;
TOperator op = HlslOpMap::binary(peek());
PrecedenceLevel tokenLevel = HlslOpMap::precedenceLevel(op);
if (tokenLevel < precedenceLevel)
return true;
do {
// ... op
TSourceLoc loc = token.loc;
advanceToken();
// ... expression
TIntermTyped* rightNode = nullptr;
if (! acceptBinaryExpression(rightNode, (PrecedenceLevel)(precedenceLevel + 1))) {
expected("expression");
return false;
}
node = intermediate.addBinaryMath(op, node, rightNode, loc);
if (! peekTokenClass(EHTokComma))
return true;
} while (true);
}
// Accept an assignment expression, where assignment operations
// associate right-to-left. This is, it is implicit, for example
//
// a op (b op (c op d))
//
// assigment_expression
// : binary_expression op binary_expression op binary_expression ...
//
bool HlslGrammar::acceptAssignmentExpression(TIntermTyped*& node)
{
if (! acceptBinaryExpression(node, PlLogicalOr))
return false;
TOperator assignOp = HlslOpMap::assignment(peek());
if (assignOp == EOpNull)
return true;
// ... op
TSourceLoc loc = token.loc;
advanceToken();
// ... binary_expression
// But, done by recursing this function, which automatically
// gets the right-to-left associativity.
TIntermTyped* rightNode = nullptr;
if (! acceptAssignmentExpression(rightNode)) {
expected("assignment expression");
return false;
}
node = intermediate.addAssign(assignOp, node, rightNode, loc);
if (! peekTokenClass(EHTokComma))
return true;
return true;
}
// Only process the next token if it is an identifier.
// Return true if it was an identifier.
bool HlslGrammar::acceptIdentifier(HlslToken& idToken)
{
if (peekTokenClass(EHTokIdentifier)) {
idToken = token;
advanceToken();
return true;
}
return false;
}
// declaration
// : SEMICOLON
// : fully_specified_type SEMICOLON
// | fully_specified_type identifier SEMICOLON
// | fully_specified_type identifier = expression SEMICOLON
// | fully_specified_type identifier function_parameters SEMICOLON // function prototype
// | fully_specified_type identifier function_parameters COLON semantic compound_statement // function definition
//
// 'node' could get created if the declaration creates code, like an initializer
// or a function body.
//
bool HlslGrammar::acceptDeclaration(TIntermNode*& node)
{
node = nullptr;
// fully_specified_type
TType type;
if (! acceptFullySpecifiedType(type))
return false;
// identifier
HlslToken idToken;
if (acceptIdentifier(idToken)) {
// = expression
TIntermTyped* expressionNode = nullptr;
if (acceptTokenClass(EHTokEqual)) {
if (! acceptExpression(expressionNode)) {
expected("initializer");
return false;
}
}
// SEMICOLON
if (acceptTokenClass(EHTokSemicolon)) {
node = parseContext.declareVariable(idToken.loc, *idToken.string, type, 0, expressionNode);
return true;
}
// function_parameters
TFunction* function = new TFunction(idToken.string, type);
if (acceptFunctionParameters(*function)) {
// COLON semantic
acceptSemantic();
// compound_statement
if (peekTokenClass(EHTokLeftBrace))
return acceptFunctionDefinition(*function, node);
// SEMICOLON
if (acceptTokenClass(EHTokSemicolon))
return true;
return false;
}
}
// SEMICOLON
if (acceptTokenClass(EHTokSemicolon))
return true;
return true;
}
// compilationUnit
// : list of externalDeclaration
//
bool HlslGrammar::acceptCompilationUnit()
{
TIntermNode* unitNode = nullptr;
while (! peekTokenClass(EHTokNone)) {
// externalDeclaration
TIntermNode* declarationNode;
if (! acceptDeclaration(declarationNode))
return false;
// hook it up
unitNode = intermediate.growAggregate(unitNode, declarationNode);
}
// set root of AST
intermediate.setTreeRoot(unitNode);
return true;
}
// postfix_expression
// : LEFT_PAREN expression RIGHT_PAREN
// | literal
// | constructor
// | identifier
// | function_call
// | postfix_expression LEFT_BRACKET integer_expression RIGHT_BRACKET
// | postfix_expression DOT IDENTIFIER
// | postfix_expression INC_OP
// | postfix_expression DEC_OP
//
bool HlslGrammar::acceptPostfixExpression(TIntermTyped*& node)
{
// Not implemented as self-recursive:
// The logical "right recursion" is done with an loop at the end
// idToken will pick up either a variable or a function name in a function call
HlslToken idToken;
// LEFT_PAREN expression RIGHT_PAREN
if (acceptTokenClass(EHTokLeftParen)) {
if (! acceptExpression(node)) {
expected("expression");
return false;
}
if (! acceptTokenClass(EHTokRightParen)) {
expected("right parenthesis");
return false;
}
} else if (acceptLiteral(node)) {
// literal (nothing else to do yet), go on to the
} else if (acceptConstructor(node)) {
// constructor (nothing else to do yet)
} else if (acceptIdentifier(idToken)) {
// identifier or function_call name
if (! peekTokenClass(EHTokLeftParen)) {
node = parseContext.handleVariable(idToken.loc, idToken.symbol, token.string);
} else if (acceptFunctionCall(idToken, node)) {
// function_call (nothing else to do yet)
} else {
expected("function call arguments");
return false;
}
}
do {
TSourceLoc loc = token.loc;
TOperator postOp = HlslOpMap::postUnary(peek());
// Consume only a valid post-unary operator, otherwise we are done.
switch (postOp) {
case EOpIndexDirectStruct:
case EOpIndexIndirect:
case EOpPostIncrement:
case EOpPostDecrement:
advanceToken();
break;
default:
return true;
}
// We have a valid post-unary operator, process it.
switch (postOp) {
case EOpIndexDirectStruct:
// todo
break;
case EOpIndexIndirect:
{
TIntermTyped* indexNode = nullptr;
if (! acceptExpression(indexNode) ||
! peekTokenClass(EHTokRightBracket)) {
expected("expression followed by ']'");
return false;
}
// todo: node = intermediate.addBinaryMath(
}
case EOpPostIncrement:
case EOpPostDecrement:
node = intermediate.addUnaryMath(postOp, node, loc);
break;
default:
assert(0);
break;
}
} while (true);
}
