%--------------------------------------------------------------------------
% NAME:   tag2mo
%
%         Return the molecule name for a given tag string.
%
%         For example: tag2mo('O3-666') gives 'O3'.
%
%         The molecule name is considered to stop at first ',', '-' or ' '.
%
%         No checks are performed that the string is a valid ARTS tag 
%         string.
%
% FORMAT: mo = tag2mo( tag )
%
% OUT:    mo    String with molecule name.
% IN:     tag   Tag string, e.g. H2O-161.
%--------------------------------------------------------------------------

% HISTORY: 2002.01.08  Created by Patrick Eriksson.


function mo = tag2mo( tag )


i = find( tag == '-' | tag == ',' | tag == ' ' );

if isempty( i )

  mo = tag;

else

  mo = tag(1:(i(1)-1));

end