samer@36: % binder - sort of monadic bind for sequences.
samer@3: %
samer@36: % binder ::
samer@3: %    seq(A)				~ 'the first sequence',
samer@3: %	  (A->seq(A))     ~ 'function to return second sequence given last element of first'
samer@3: % -> seq(A)          ~ 'resultant sequence'.
samer@3: %
samer@3: % The resulting sequence consists of the entire sequence represented by the
samer@3: % first parameter, followed by the sequence obtained by applying the second
samer@23: % parameter to the last element of the first sequence. 
samer@3: %
samer@3: % Example:
samer@3: %
samer@3: %    gather(2,bindcat(cellseq({1,2,3,4}),@(x)take(head(x),0)))
samer@3: %
samer@3: % ans = 1  2  3  4  0  0  0  0
samer@36: classdef binder < seq
samer@3: 	properties (GetAccess=private, SetAccess=private)
samer@3: 		source
samer@3: 		nfn
samer@3: 		x
samer@3: 	end
samer@3: 	methods
samer@36: 		function o=binder(X,F)
samer@3: 			o.source=X;
samer@3: 			o.nfn=F;
samer@3: 			o.x=head(X);
samer@3: 		end
samer@3: 
samer@3: 		function z=elsize(o), z=size(o.x); end
samer@3: 		function s=tostring(o), s=sprintf('%s >>= %s',tostring(o.source),tostring(o.nfn)); end
samer@3: 		function x=head(o), x=o.x; end
samer@3: 		function o=next(o),
samer@3: 			o.source=next(o.source); 
samer@3: 			if isempty(o.source), o=o.nfn(o.x); 
samer@3: 			else o.x=head(o.source);
samer@3: 			end
samer@3: 		end
samer@3: 	end
samer@3: end