private sign Parse_sign()
{
if (_index >= _tokens.Count())
{
return(null);
} // must be first line on any atom
/*sign:
* "+" | "-" */
var _data = _tokens[_index];
var _result = new sign(_data);
if (_result.is_sign)
{
_index++;
return(_result);
}
else
{
return(null);
}
}
public exponent(SpecialToken _ident, digit_sequence _digit_sequence, sign _sign = null)
{
ident = _ident;
digit_sequence = _digit_sequence;
sign = _sign;
expression = "E" + sign?.expression + digit_sequence.expression;
}
//-----------------------------------------------------------
public number Parse_number()
{
/*number:
* sign? integer-constant
| sign? floating-point-constant */
var _backtrackindex_1 = _index;
number _self = null;
List <sign> __sign = new List <sign>();
var _sign = Parse_sign();
while (_sign != null)
{
__sign.Add(_sign); _sign = Parse_sign();
}
_sign = new sign(__sign);
//var _sign = Parse_sign();
var _backtrackindex_2 = _index;
var _integer_constant = Parse_integer_constant();
if (_integer_constant != null && ((_index < _tokens.Count() && _tokens[_index].StringValue != ".") || _index == _tokens.Count()))
{
_self = new number(_sign, _integer_constant);
return(_self);
}
if (_index < _tokens.Count())
{
_index = _backtrackindex_2;
}
else
{
return(null);
}
var _floating_point_constant = Parse_floating_point_constant();
if (_floating_point_constant != null)
{
_self = new number(_sign, _floating_point_constant);
return(_self);
}
if (_self == null)
{
_index = _backtrackindex_1;
}
else
{
return(null);
}
return(_self);
}
// THIS SECTION IS KIND OF CHEATING. I SHOULD DO THIS IN A BNF SEQUENCE.
// GO BACK AND REDO THIS !!!!
public sign(List <sign> _sign_sequnce)
{
sign current = null;
sign prev = null;
string _expression = string.Empty;
#region loop
foreach (var _sign in _sign_sequnce)
{
/*
* -- = +
++ = +
++ -+ = -
+- = -
*/
current = _sign;
_expression += current.expression;
if (prev != null)
{
if ( // do we have a --?
current.token.StringValue == "-" && prev.token.StringValue == "-" ||
prev.token.StringValue == "-" && current.token.StringValue == "-"
// or do we have a ++?
|| (current.token.StringValue == "+" && prev.token.StringValue == "+") ||
(prev.token.StringValue == "+" && current.token.StringValue == "+")
)
{
current = new sign(new SpecialToken('+'));
}
else
{
current = new sign(new SpecialToken('-'));
}
}
prev = current;
}
#endregion
if (_sign_sequnce.Count > 0)
{
token = current.token;
is_sign = true;
expression = _expression;
}
else
{
is_sign = false;
}
}
public number(sign _sign, floating_point_constant _floating_point_constant)
{
sign = _sign;
floating_point_constant = _floating_point_constant;
expression = sign == null ? floating_point_constant.expression : sign.expression + floating_point_constant.expression;
}
public number(sign _sign, integer_constant _integer_constant)
{
sign = _sign;
integer_constant = _integer_constant;
expression = sign == null ? integer_constant.expression : sign.expression + integer_constant.expression;
}