private Expression Factor()
{
Expression expr = Unary();
while (Match(LexemeType.SLASH) || Match(LexemeType.STAR))
{
Lexeme op = Previous();
Expression right = Unary();
expr = new Expression.Binary(expr, op, right);
}
return(expr);
}
private Expression Comparison()
{
Expression expr = Term();
while (Match(LexemeType.GREATER) || Match(LexemeType.GREATER_EQUAL) || Match(LexemeType.LESS) || Match(LexemeType.LESS_EQUAL))
{
Lexeme op = Previous();
Expression right = Term();
expr = new Expression.Binary(expr, op, right);
}
return(expr);
}
private Expression Term()
{
Expression expr = Factor();
while (Match(LexemeType.MINUS) || Match(LexemeType.PLUS))
{
Lexeme op = Previous();
Expression right = Factor();
expr = new Expression.Binary(expr, op, right);
}
return(expr);
}
private Expression Equality()
{
Expression expr = Comparison();
while (Match(LexemeType.BANG_EQUAL) || Match(LexemeType.EQUAL_EQUAL))
{
Lexeme op = Previous();
// Bug - I need to consume the second operator when doing comparisions.
// Hack I need to figure out a better way to do this.
Lexeme secondOp = Advance();
if (secondOp.LexemeType == LexemeType.EQUAL)
{
op.AddToken(secondOp);
op.LexemeType = LexemeType.EQUAL_EQUAL;
}
// see what it is? maybe update the lexeme?
Expression right = Comparison();
expr = new Expression.Binary(expr, op, right);
}
return(expr);
}
