function out = issing(f)
%ISSING   Test if a FUN object is built upon SINGFUN.
%   out = ISSING(F) returns logical true if its ONEFUN is a SINGFUN and false 
%   otherwise.

% [TODO]: Should the name of this function go camel case? So far, all is*
% function are named without camel case.

% Copyright 2017 by The University of Oxford and The Chebfun Developers.
% See http://www.chebfun.org/ for Chebfun information.

out = isa(f.onefun, 'singfun');

end
