public IParseNode Parse(TokenWalker walker)
{
Debug.Assert(TermParser != null);
IParseNode result;
if (walker.NextIs <MinusToken>())
{
var lexem = walker.Pop();
result = new UnaryMinusOperator(TermParser.Parse(walker), lexem.Position);
}
else
{
result = TermParser.Parse(walker);
}
while (walker.NextIsLineOperator())
{
var lexem = walker.Pop();
result = lexem.Token switch
{
MinusToken _ => new MinusOperator(result, TermParser.Parse(walker), lexem.Position),
PlusToken _ => new PlusOperator(result, TermParser.Parse(walker), lexem.Position),
_ => result
};
}
return(result);
}
}
public void Visit(UnaryMinusOperator op)
{
op.Operand.Accept(this);
_stack.Push(-_stack.Pop());
}
public void Visit(UnaryMinusOperator op)
{
Visit((UnaryOperator)op);
}
public void Visit(UnaryMinusOperator op)
{
_resultBuilder.AppendFormat("-");
op.Operand.Accept(this);
}
