private Identifiable parseFunctionCall(IdentifierToken identifierToken) throws ParserException {
consumeCharacter('(');
try {
if (peek().id() == ')') {
++position;
return Functions.getFunction(identifierToken.getPosition(), identifierToken.value);
}
List<RValue> args = new ArrayList<RValue>();
loop:
while (true) {
args.add(parseExpression(false));
final Token current = peek();
++position;
switch (current.id()) {
case ',':
continue;
case ')':
break loop;
default:
throw new ParserException(current.getPosition(), "Unmatched opening bracket");
}
}
return Functions.getFunction(
identifierToken.getPosition(),
identifierToken.value,
args.toArray(new RValue[args.size()]));
} catch (NoSuchMethodException e) {
throw new ParserException(
identifierToken.getPosition(), "Function '" + identifierToken.value + "' not found", e);
}
}
private RValue parseStatements(boolean singleStatement) throws ParserException {
List<RValue> statements = new ArrayList<RValue>();
loop:
while (true) {
if (position >= tokens.size()) {
break;
}
final Token current = peek();
switch (current.id()) {
case '{':
consumeCharacter('{');
statements.add(parseStatements(false));
consumeCharacter('}');
if (singleStatement) {
break loop;
}
break;
case '}':
break loop;
case 'k':
final String keyword = ((KeywordToken) current).value;
switch (keyword.charAt(0)) {
case 'i':
{ // if
++position;
final RValue condition = parseBracket();
final RValue truePart = parseStatements(true);
final RValue falsePart;
if (hasKeyword("else")) {
++position;
falsePart = parseStatements(true);
} else {
falsePart = null;
}
statements.add(
new Conditional(current.getPosition(), condition, truePart, falsePart));
break;
}
case 'w':
{ // while
++position;
final RValue condition = parseBracket();
final RValue body = parseStatements(true);
statements.add(new While(current.getPosition(), condition, body, false));
break;
}
case 'd':
{ // do
++position;
final RValue body = parseStatements(true);
consumeKeyword("while");
final RValue condition = parseBracket();
statements.add(new While(current.getPosition(), condition, body, true));
break;
}
case 'f':
{ // for
++position;
consumeCharacter('(');
int oldPosition = position;
final RValue init = parseExpression(true);
// if ((init instanceof LValue) && )
if (peek().id() == ';') {
++position;
final RValue condition = parseExpression(true);
consumeCharacter(';');
final RValue increment = parseExpression(true);
consumeCharacter(')');
final RValue body = parseStatements(true);
statements.add(new For(current.getPosition(), init, condition, increment, body));
} else {
position = oldPosition;
final Token variableToken = peek();
if (!(variableToken instanceof IdentifierToken)) {
throw new ParserException(variableToken.getPosition(), "Expected identifier");
}
// In theory, I should have to create non-existant variables here.
// However, the java-for parsing attempt further up already takes care of that :)
RValue variable = variables.get(((IdentifierToken) variableToken).value);
if (!(variable instanceof LValue)) {
throw new ParserException(variableToken.getPosition(), "Expected variable");
}
++position;
final Token equalsToken = peek();
if (!(equalsToken instanceof OperatorToken)
|| !((OperatorToken) equalsToken).operator.equals("=")) {
throw new ParserException(
variableToken.getPosition(), "Expected '=' or a term and ';'");
}
++position;
final RValue first = parseExpression(true);
consumeCharacter(',');
final RValue last = parseExpression(true);
consumeCharacter(')');
final RValue body = parseStatements(true);
statements.add(
new SimpleFor(current.getPosition(), (LValue) variable, first, last, body));
}
break;
}
case 'b': // break
++position;
statements.add(new Break(current.getPosition(), false));
break;
case 'c': // continue
++position;
statements.add(new Break(current.getPosition(), true));
break;
case 'r': // return
++position;
statements.add(new Return(current.getPosition(), parseExpression(true)));
if (peek().id() == ';') {
++position;
break;
} else {
break loop;
}
default:
throw new ParserException(
current.getPosition(), "Unimplemented keyword '" + keyword + "'");
}
if (singleStatement) {
break loop;
}
break;
default:
statements.add(parseExpression(true));
if (peek().id() == ';') {
++position;
if (singleStatement) {
break loop;
}
break;
} else {
break loop;
}
}
}
switch (statements.size()) {
case 0:
if (singleStatement) {
throw new ParserException(peek().getPosition(), "Statement expected.");
} else {
return new Sequence(peek().getPosition());
}
case 1:
return statements.get(0);
default:
return new Sequence(
peek().getPosition(), statements.toArray(new RValue[statements.size()]));
}
}
private void assertCharacter(char character) throws ParserException {
final Token next = peek();
if (next.id() != character) {
throw new ParserException(next.getPosition(), "Expected '" + character + "'");
}
}
private final RValue parseExpression(boolean canBeEmpty) throws ParserException {
LinkedList<Identifiable> halfProcessed = new LinkedList<Identifiable>();
// process brackets, numbers, functions, variables and detect prefix operators
boolean expressionStart = true;
loop:
while (position < tokens.size()) {
final Token current = peek();
switch (current.id()) {
case '0':
halfProcessed.add(new Constant(current.getPosition(), ((NumberToken) current).value));
++position;
expressionStart = false;
break;
case 'i':
final IdentifierToken identifierToken = (IdentifierToken) current;
++position;
final Token next = peek();
if (next.id() == '(') {
halfProcessed.add(parseFunctionCall(identifierToken));
} else {
RValue variable = variables.get(identifierToken.value);
if (variable == null) {
if (next instanceof OperatorToken && ((OperatorToken) next).operator.equals("=")) {
// Ugly hack to make temporary variables work while not sacrificing error reporting.
variables.put(identifierToken.value, variable = new Variable(0));
} else {
throw new ParserException(
current.getPosition(), "Variable '" + identifierToken.value + "' not found");
}
}
halfProcessed.add(variable);
}
expressionStart = false;
break;
case '(':
halfProcessed.add(parseBracket());
expressionStart = false;
break;
case ',':
case ')':
case '}':
case ';':
break loop;
case 'o':
if (expressionStart) {
// Preprocess prefix operators into unary operators
halfProcessed.add(new UnaryOperator((OperatorToken) current));
} else {
halfProcessed.add(current);
}
++position;
expressionStart = true;
break;
default:
halfProcessed.add(current);
++position;
expressionStart = false;
break;
}
}
if (halfProcessed.isEmpty() && canBeEmpty) {
return new Sequence(peek().getPosition());
}
return ParserProcessors.processExpression(halfProcessed);
}
