function q = dfsa_delta(DFSA,q,s)
% perform the transition from (q,s) to q'
% see str2dfsa.m for basic dfsa definitions

% note: we will not check alphabet compatibility here
% any out-of-range letter will result in an error

ns = find(DFSA.ALF==s);
%ns = s-DFSA.ALF(1)+1;
if isempty(ns)
  error(['unknown letter s = ' s ' ALF = ' DFSA.ALF])
end
q = DFSA.delta(q,ns);
%q = DFSA.delta(q,s);

return



function q = dfsa_delta_old(DFSA,q,s)
% perform the transition from (q,s) to q'
% see str2dfsa.m for basic dfsa definitions

% note: we will not check alphabet compatibility here
% any out-of-range type phenomenon will be treated as a rejection

if (q==DFSA.qd)
  % this is the abosorbing "default" state
  % don't do anything -- stay here
else
  [b,q] = ind_in_range([q,s],DFSA.delta);  % is the transition allowed?
  %q = DFSA.delta(q,s)+0;
  q = q + 0; % unsparse
  if ~q
    q = DFSA.qd;
  end
  
  % OLD WAY:
  %[b,x] = ind_in_range([q,s],DFSA.delta);  % is the transition allowed?
  %if b, b = ~isempty(x{1}); end;  
  %if b
  %  q = x{1};
  %else
  %  q = DFSA.qd; % default state <--> rejection
  %end
end
return