private ExpressionNode JExpression() throws SyntaxException {
        try {
            if (iterator.current().type().is(Token.Type.Constant)) {
                return Const();
            } else if (iterator.current().type().is(Token.Type.LEFT_BRACKET)) {
                nextToken();
                ExpressionNode node = Expression();
                RightBracket();
                return node;
            } else {
                Position pos = iterator.current().coordinates().starting();
                return new VariableLeaf(Identifier(), pos);
            }
        } catch(SyntaxException ex) {
            throw ex;
        } catch(Exception ex) {
            throw (NonAnalysisException)new NonAnalysisException(ex)
                    .initPosition(iterator.current().coordinates().starting())
                    .Log("ru.bmstu.iu9.compiler.syntax");
        }
    }