public ITreeNode Expr()
{
ITreeNode node = term();
while ((_currentToken.type == Types.type.PLUS) ||
(_currentToken.type == Types.type.MINUS) ||
(_currentToken.type == Types.type.OR) ||
(_currentToken.type == Types.type.AND))
{
Token token = _currentToken;
_currentToken = lexer.GetNextToken();
node = new BinarNode(token, node, term());
}
if ((_currentToken.type == Types.type.SEMICOMA) ||
(_currentToken.type == Types.type.COMMA) ||
(_currentToken.type == Types.type.END))
{
return(node);
}
if (_currentToken.type == Types.type.CURLRBRACKET)
{
return(node);
}
if (_currentToken.type == Types.type.RBRACKET)
{
return(node);
}
throw new BadSyntaxException(lexer.GetPosition(), _currentToken.value);
}
ITreeNode factor()
{
//factor : INTEGER | LPAREN expr RPAREN
ITreeNode p = Base();
while (_currentToken.type == Types.type.POWER)
{
Token token = _currentToken;
_currentToken = lexer.GetNextToken();
p = new BinarNode(token, p, factor());
}
return(p);
}
ITreeNode term()
{
//term : factor ((MUL | DIV) factor)*
ITreeNode node = factor();
while ((_currentToken.type == Types.type.MULT) ||
(_currentToken.type == Types.type.DIV) || (_currentToken.type == Types.type.MOD) ||
(_currentToken.type == Types.type.LARGER) || (_currentToken.type == Types.type.SMALLEREQUAL) ||
(_currentToken.type == Types.type.SMALLER) || (_currentToken.type == Types.type.LARGEREQUAL) ||
(_currentToken.type == Types.type.NOTEQUAL) || (_currentToken.type == Types.type.ISEQUAL))
{
Token token = _currentToken;
_currentToken = lexer.GetNextToken();
node = new BinarNode(token, node, factor());
}
return(node);
}
ITreeNode Base()
{
if (_currentToken.type == Types.type.IF)
{
Token token = _currentToken;
_currentToken = lexer.GetNextToken();
if (_currentToken.type == Types.type.LBRACKET)
{
_currentToken = lexer.GetNextToken();
ITreeNode condition = Expr();
if ((_currentToken.type == Types.type.RBRACKET))
{
_currentToken = lexer.GetNextToken();
}
else
{
throw new BadSyntaxException(lexer.GetPosition(), _currentToken.value);
}
if (_currentToken.type == Types.type.CURLLBRACKET)
{
_currentToken = lexer.GetNextToken();
return(new IfNode(token, condition, Block()));
}
return(new IfNode(token, condition, Expr()));
}
else
{
throw new BadSyntaxException(lexer.GetPosition(), _currentToken.value);
}
}
if (_currentToken.type == Types.type.WHILE)
{
Token token = _currentToken;
_currentToken = lexer.GetNextToken();
if (_currentToken.type == Types.type.LBRACKET)
{
_currentToken = lexer.GetNextToken();
ITreeNode condition = Expr();
if ((_currentToken.type == Types.type.RBRACKET))
{
_currentToken = lexer.GetNextToken();
}
else
{
throw new BadSyntaxException(lexer.GetPosition(), _currentToken.value);
}
if (_currentToken.type == Types.type.CURLLBRACKET)
{
_currentToken = lexer.GetNextToken();
return(new LoopNode(token, condition, Block()));
}
return(new LoopNode(token, condition, Expr()));
}
else
{
throw new BadSyntaxException(lexer.GetPosition(), _currentToken.value);
}
}
if ((_currentToken.type == Types.type.MINUS) || (_currentToken.type == Types.type.PLUS))
{
Token token = _currentToken;
_currentToken = lexer.GetNextToken();
ITreeNode node = new UnarNode(token, factor());
return(node);
}
if ((_currentToken.type == Types.type.MAX) || (_currentToken.type == Types.type.MIN))
{
Token token = _currentToken;
_currentToken = lexer.GetNextToken();
if (_currentToken.type != Types.type.LBRACKET)
{
throw new BadSyntaxException(lexer.GetPosition(), token.value);
}
_currentToken = lexer.GetNextToken();
ITreeNode _leftNode = Expr();
if (_currentToken.type == Types.type.COMMA)
{
_currentToken = lexer.GetNextToken();
ITreeNode p = new BinarNode(token, _leftNode, Expr());
_currentToken = lexer.GetNextToken();
return(p);
}
throw new BadSyntaxException(lexer.GetPosition(), _currentToken.value);
}
if (_currentToken.type == Types.type.INTEGER)
{
ITreeNode p = new AtomNode(_currentToken);
_currentToken = lexer.GetNextToken();
return(p);
}
if (_currentToken.type == Types.type.VAR)
{
Token token = _currentToken;
ITreeNode p = new AtomNode(_currentToken);
_currentToken = lexer.GetNextToken();
if (_currentToken.type == Types.type.EQUAL)
{
token = _currentToken;
_currentToken = lexer.GetNextToken();
ITreeNode formula = Expr();
p = new BinarNode(token, p, formula);
}
if ((_currentToken.type == Types.type.INC) || (_currentToken.type == Types.type.DEC))
{
token = _currentToken;
_currentToken = lexer.GetNextToken();
p = new UnarNode(token, p);
}
return(p);
}
if (_currentToken.type == Types.type.NOT)
{
Token token = _currentToken;
_currentToken = lexer.GetNextToken();
ITreeNode node = new UnarNode(token, factor());
return(node);
}
if (_currentToken.type == Types.type.LBRACKET)
{
_currentToken = lexer.GetNextToken();
ITreeNode p = Expr();
if ((_currentToken.type == Types.type.RBRACKET))
{
_currentToken = lexer.GetNextToken();
}
else
{
throw new BadSyntaxException(lexer.GetPosition(), _currentToken.value);
}
return(p);
}
if (_currentToken.type == Types.type.CURLLBRACKET)
{
_currentToken = lexer.GetNextToken();
return(Block());
}
if (_currentToken.type == Types.type.COMMENT)
{
_currentToken = lexer.GetNextToken();
return(Base());
}
throw new BadSyntaxException(lexer.GetPosition(), _currentToken.value);
}
