int Term()
{
var result = this.Factor();
while (MathsOperators.IsMultDiv(_currentToken.TokenType))
{
Token operation = _currentToken;
this.Eat(operation.TokenType);
result = MathsOperators.Operate(operation.TokenType, result, this.Factor());
}
return(result);
}
int Expr()
{
// this enforces the structure of mathiness on what we are doing. It expects the following format
// Term We check for operators with higher precedence (*/ /) and act on them first
// return the result
int result = this.Term();
// OP -- at this point we have moved forward (via Term method) and so should be at an the operator.
// however if the expression is unary aka '3' there is no next token (EOF), so skip to the end and return the result.s
while (MathsOperators.IsPlusMinus(_currentToken.TokenType))
{
Token operation = _currentToken;
// moves it forward to the right
// reassigns current token too.
this.Eat(operation.TokenType);
// DO THE MATHS!
// NOTE we have a Term operation here, just in case there are more terms than expected
result = MathsOperators.Operate(operation.TokenType, result, this.Term());
}
return(result);
}