private ArithmeticExpression parseArithmeticExpression() throws CompileException {
Term term = parseTerm();
ASTList<TermBlock> termBlocks = new ASTList<TermBlock>();
while (currentToken.getTokenKind() == TokenKind.TERMOPERATOR) {
termBlocks.add(new TermBlock(parsePlusMinusOperator(), parseTerm()));
}
if (termBlocks.isEmpty()) return new ArithmeticExpression(term);
else return new ArithmeticExpression(term, termBlocks);
}
private Term parseTerm() throws CompileException {
ASTList<FactorBlock> factorBlocks = new ASTList<FactorBlock>();
Factor factor = parseFactor();
while (currentToken.getTokenKind() == TokenKind.FACTOROPERATOR) {
factorBlocks.add(new FactorBlock(parseMultiplyDivideOperator(), parseFactor()));
}
if (factorBlocks.isEmpty()) return new Term(factor);
else return new Term(factor, factorBlocks);
}
private Program parseProgram() throws CompileException {
ASTList<VarDeclaration> varDeclarations = new ASTList<VarDeclaration>();
ASTList<EventCommand> eventCommands = new ASTList<EventCommand>();
while (currentToken.getTokenKind() == TokenKind.TYPE)
varDeclarations.add(parseVarDeclaration());
while (currentToken.getTokenKind() == TokenKind.EVENT) eventCommands.add(parseEventCommand());
accept(TokenKind.EOT);
if (!eventCommands.isEmpty() && varDeclarations.isEmpty())
// only eventCommands
return new Program(
eventCommands, true); // the boolean is garbage required as java uses type erasure
else if (eventCommands.isEmpty() && !varDeclarations.isEmpty())
// only varDeclarations
return new Program(varDeclarations);
else
// Both
return new Program(varDeclarations, eventCommands);
}
private IfStatement parseIfStatement() throws CompileException {
ASTList<Command> commandIfs = new ASTList<Command>();
ASTList<ElseIfBlock> elseIfBlocks = new ASTList<ElseIfBlock>();
ASTList<Command> commandElses = new ASTList<Command>();
accept(TokenKind.IF);
accept(TokenKind.LPAREN);
BooleanExpression booleanExpressionIf = parseBooleanExpression();
accept(TokenKind.RPAREN);
accept(TokenKind.LCRLPARAN);
while (currentToken.getTokenKind() == TokenKind.MOVE
|| currentToken.getTokenKind() == TokenKind.GOTO
|| currentToken.getTokenKind() == TokenKind.SET
|| currentToken.getTokenKind() == TokenKind.IDENTIFIER
|| currentToken.getTokenKind() == TokenKind.IF) {
// Its a command
commandIfs.add(parseCommand());
}
accept(TokenKind.RCRLPARAN);
// We're at the end of the IF clause
while (currentToken.getTokenKind() == TokenKind.ELSEIF) {
acceptIt();
accept(TokenKind.LPAREN);
BooleanExpression orExpression = parseBooleanExpression();
accept(TokenKind.RPAREN);
accept(TokenKind.LCRLPARAN);
ASTList<Command> commandOrs = new ASTList<Command>();
while (currentToken.getTokenKind() == TokenKind.MOVE
|| currentToken.getTokenKind() == TokenKind.GOTO
|| currentToken.getTokenKind() == TokenKind.SET
|| currentToken.getTokenKind() == TokenKind.IDENTIFIER
|| currentToken.getTokenKind() == TokenKind.IF) {
// Its a command
commandOrs.add(parseCommand());
}
elseIfBlocks.add(new ElseIfBlock(orExpression, commandOrs));
accept(TokenKind.RCRLPARAN);
}
if (currentToken.getTokenKind() == TokenKind.ELSE) {
acceptIt();
accept(TokenKind.LCRLPARAN);
while (currentToken.getTokenKind() == TokenKind.MOVE
|| currentToken.getTokenKind() == TokenKind.GOTO
|| currentToken.getTokenKind() == TokenKind.SET
|| currentToken.getTokenKind() == TokenKind.IDENTIFIER
|| currentToken.getTokenKind() == TokenKind.IF) {
// Its a command
commandElses.add(parseCommand());
}
accept(TokenKind.RCRLPARAN);
}
// Find out what constructor to call
if (elseIfBlocks.isEmpty() && commandElses.isEmpty()) {
return new IfStatement(booleanExpressionIf, commandIfs);
} else if (!elseIfBlocks.isEmpty() && commandElses.isEmpty()) {
return new IfStatement(
booleanExpressionIf,
commandIfs,
elseIfBlocks,
true); // the boolean is garbage required as java uses type erasure
} else if (elseIfBlocks.isEmpty() && !commandElses.isEmpty()) {
return new IfStatement(booleanExpressionIf, commandIfs, commandElses);
} else {
return new IfStatement(booleanExpressionIf, commandIfs, elseIfBlocks, commandElses);
}
}