/**
* Parse a Triangle SingleDeclarationParser.
*
* <p>Single-Declaration ::= const Identifier ~ Expression | var Identifier : Type-Denoter | proc
* Identifier (Formal-Parameter-Sequence) ~ Single-Command | func Identifier
* (Formal-Parameter-Sequence) : Type-Denoter ~ Expression | Type Identifier ~ Type-Denoter
*
* <p>To be overridden by the specialized command parse subclasses.
*
* @param token the initial token.
* @return the root node of the generated parse tree.
* @throws Exception if an error occurred.
*/
public void parse(Token token) throws Exception {
SingleCommandParser singleCommand = null;
ExpressionParser expression = null;
FormalParameterSequenceParser formalParameterSequence = null;
TypeDenoterParser typeDenoter = null;
EnumSet<TriangleTokenType> syncSet = null;
TypeSpec identifierType = TrianglePredefined.undefinedType;
Token identifierToken = null;
ICode routineICode = null;
token = currentToken();
switch ((TriangleTokenType) token.getType()) {
case CONST:
identifierToken = nextToken();
syncSet = EnumSet.of(TILDE);
syncSet.addAll(ExpressionParser.FIRST_FOLLOW_SET);
synchronize(IDENTIFIER, MISSING_IDENTIFIER, syncSet);
syncSet.remove(TILDE);
token = synchronize(TILDE, MISSING_TILDE, syncSet);
expression = new ExpressionParser(this);
ICodeNode expressionNode = expression.parse(token);
SymTabEntry constantId = symTabStack.lookupLocal(identifierToken.getText().toLowerCase());
// Enter the new identifier into the symbol table
// but don't set how it's defined yet.
if (constantId == null) {
constantId = symTabStack.enterLocal(identifierToken.getText().toLowerCase());
constantId.setDefinition(DefinitionImpl.CONSTANT);
constantId.setAttribute(CONSTANT_VALUE, expressionNode);
constantId.appendLineNumber(identifierToken.getLineNumber());
constantId.setTypeSpec(expressionNode.getTypeSpec());
} else {
errorHandler.flag(identifierToken, IDENTIFIER_REDEFINED, this);
}
break;
case VAR:
identifierToken = nextToken();
syncSet = EnumSet.of(COLON);
syncSet.addAll(TypeDenoterParser.FIRST_FOLLOW_SET);
synchronize(IDENTIFIER, MISSING_IDENTIFIER, syncSet);
syncSet.remove(COLON);
token = synchronize(COLON, MISSING_COLON, syncSet);
typeDenoter = new TypeDenoterParser(this);
identifierType = typeDenoter.parse(token);
SymTabEntry variableId = symTabStack.lookupLocal(identifierToken.getText().toLowerCase());
// Enter the new identifier into the symbol table
// but don't set how it's defined yet.
if (variableId == null) {
variableId = symTabStack.enterLocal(identifierToken.getText().toLowerCase());
variableId.setDefinition(DefinitionImpl.VARIABLE);
variableId.appendLineNumber(identifierToken.getLineNumber());
variableId.setTypeSpec(identifierType);
} else {
errorHandler.flag(identifierToken, IDENTIFIER_REDEFINED, this);
}
break;
case PROC:
identifierToken = nextToken();
routineICode = ICodeFactory.createICode();
syncSet = EnumSet.of(LEFT_PAREN);
syncSet.addAll(FormalParameterSequenceParser.FIRST_FOLLOW_SET);
token = synchronize(IDENTIFIER, MISSING_IDENTIFIER, syncSet);
syncSet.remove(LEFT_PAREN);
token = synchronize(LEFT_PAREN, MISSING_LEFT_PAREN, syncSet);
SymTabEntry procId = symTabStack.lookupLocal(identifierToken.getText().toLowerCase());
// Enter the new identifier into the symbol table
// but don't set how it's defined yet.
if (procId == null) {
procId = symTabStack.enterLocal(identifierToken.getText().toLowerCase());
procId.setTypeSpec(TrianglePredefined.undefinedType);
procId.setDefinition(DefinitionImpl.PROCEDURE);
procId.appendLineNumber(identifierToken.getLineNumber());
procId.setAttribute(ROUTINE_SYMTAB, symTabStack.push());
procId.setAttribute(ROUTINE_ICODE, routineICode);
} else {
errorHandler.flag(identifierToken, IDENTIFIER_REDEFINED, this);
procId = null;
}
formalParameterSequence = new FormalParameterSequenceParser(this);
ArrayList<SymTabEntry> procParamList = formalParameterSequence.parse(token);
syncSet = EnumSet.of(TILDE);
syncSet.addAll(SingleCommandParser.FIRST_FOLLOW_SET);
token = synchronize(RIGHT_PAREN, MISSING_RIGHT_PAREN, syncSet);
syncSet.remove(TILDE);
token = synchronize(TILDE, MISSING_TILDE, syncSet);
singleCommand = new SingleCommandParser(this);
routineICode.setRoot(singleCommand.parse(token));
if (procId != null) {
procId.setAttribute(ROUTINE_PARMS, procParamList);
}
symTabStack.pop();
break;
case FUNC:
identifierToken = nextToken();
routineICode = ICodeFactory.createICode();
SymTabEntry funcId = symTabStack.lookupLocal(identifierToken.getText().toLowerCase());
// Enter the new identifier into the symbol table
// but don't set how it's defined yet.
if (funcId == null) {
funcId = symTabStack.enterLocal(identifierToken.getText().toLowerCase());
funcId.setDefinition(DefinitionImpl.FUNCTION);
funcId.appendLineNumber(identifierToken.getLineNumber());
funcId.setTypeSpec(TrianglePredefined.undefinedType);
funcId.setAttribute(ROUTINE_SYMTAB, symTabStack.push());
funcId.setAttribute(ROUTINE_ICODE, routineICode);
} else {
errorHandler.flag(identifierToken, IDENTIFIER_REDEFINED, this);
funcId = null;
}
syncSet = EnumSet.of(LEFT_PAREN);
syncSet.addAll(FormalParameterSequenceParser.FIRST_FOLLOW_SET);
token = synchronize(IDENTIFIER, MISSING_IDENTIFIER, syncSet);
syncSet.remove(LEFT_PAREN);
token = synchronize(LEFT_PAREN, MISSING_LEFT_PAREN, syncSet);
formalParameterSequence = new FormalParameterSequenceParser(this);
ArrayList<SymTabEntry> funcParamList = formalParameterSequence.parse(token);
syncSet = EnumSet.of(COLON);
syncSet.addAll(TypeDenoterParser.FIRST_FOLLOW_SET);
synchronize(RIGHT_PAREN, MISSING_RIGHT_PAREN, syncSet);
syncSet.remove(COLON);
token = synchronize(COLON, MISSING_COLON, syncSet);
Token typeToken = currentToken();
typeDenoter = new TypeDenoterParser(this);
TypeSpec funcType = typeDenoter.parse(token);
syncSet = ExpressionParser.FIRST_FOLLOW_SET.clone();
token = synchronize(TILDE, MISSING_TILDE, syncSet);
expression = new ExpressionParser(this);
routineICode.setRoot(expression.parse(token));
if (funcId != null) {
funcId.setTypeSpec(funcType);
funcId.setAttribute(ROUTINE_PARMS, funcParamList);
if (!routineICode.getRoot().getTypeSpec().equals(funcType)) {
errorHandler.flag(typeToken, RETURN_TYPE_MISMATCH, this);
}
}
symTabStack.pop();
break;
case TYPE:
identifierToken = nextToken();
syncSet = EnumSet.of(TILDE);
syncSet.addAll(TypeDenoterParser.FIRST_FOLLOW_SET);
synchronize(IDENTIFIER, MISSING_IDENTIFIER, syncSet);
syncSet.remove(TILDE);
token = synchronize(TILDE, MISSING_TILDE, syncSet);
typeDenoter = new TypeDenoterParser(this);
TypeSpec typeType = typeDenoter.parse(token);
SymTabEntry typeId = symTabStack.lookupLocal(identifierToken.getText().toLowerCase());
// Enter the new identifier into the symbol table
// but don't set how it's defined yet.
if (typeId == null) {
typeId = symTabStack.enterLocal(identifierToken.getText().toLowerCase());
typeId.setDefinition(DefinitionImpl.TYPE);
typeId.appendLineNumber(identifierToken.getLineNumber());
typeId.setTypeSpec(typeType);
} else {
errorHandler.flag(token, IDENTIFIER_REDEFINED, this);
}
break;
default:
errorHandler.flag(token, MISSING_DECLARATION, this);
break;
}
}
/**
* Set the current line number as a statement node attribute.
*
* @param node ICodeNode
* @param token the initial token.
*/
protected void setLineNumber(ICodeNode node, Token token) {
if (node != null) {
node.setAttribute(LINE, token.getLineNumber());
}
}