private IExpressionNode findVariableByName(String name) {
for (IExpressionNode node : nodeList) {
if (node.getType() == IExpressionNode.VARIABLE_NODE)
if (((VariableExpressionNode) node).getName().equals(name)) return node;
}
return null;
}
private IExpressionNode assignmentOp(IExpressionNode variable) throws ParserException {
if (lookahead.token == Token.EQUALS) {
nextToken();
IExpressionNode newVariable = expression();
if (!(variable.getType() == IExpressionNode.VARIABLE_NODE))
throw new ParserException(String.format(ERR_VARIABLE, variable.toString()));
try {
variable.accept(
new SetVariable(((VariableExpressionNode) variable).getName(), newVariable.getValue()));
} catch (EvaluationException ex) {
throw new ParserException(
String.format("The variable [%s] did not return a valid value", newVariable));
}
}
return variable;
}
private IExpressionNode sumOp(IExpressionNode expression) throws ParserException {
if (lookahead.token == Token.PLUSMINUS) {
// sum_op -> PLUSMINUS term sum_op
AdditionExpressionNode sum;
if (expression.getType() == IExpressionNode.ADDITION_NODE)
sum = (AdditionExpressionNode) expression;
else sum = new AdditionExpressionNode(expression, true);
boolean positive = lookahead.sequence.equals(PLUS);
nextToken();
IExpressionNode t = term();
sum.add(t, positive);
return sumOp(sum);
}
// sum_op -> EPSILON
return expression;
}
private IExpressionNode termOp(IExpressionNode expression) throws ParserException {
if (lookahead.token == Token.MULTDIV) {
// term_op -> MULTDIV factor term_op
MultiplicationExpressionNode prod;
if (expression.getType() == IExpressionNode.MULTIPLICATION_NODE)
prod = (MultiplicationExpressionNode) expression;
else prod = new MultiplicationExpressionNode(expression, true);
boolean positive = lookahead.sequence.equals(MULT);
nextToken();
IExpressionNode f = signedFactor();
prod.add(f, positive);
return termOp(prod);
}
// term_op -> EPSILON
return expression;
}
