samer@0: % amatrix - arrow to generate sequence by scanning through an array
samer@0: %
samer@0: % amatrix :: [[N,M]] -> arrow({},{[[N]]},1..M).
samer@0: function o=amatrix(X)
samer@0: 	state=1;
samer@0: 	len=size(X,2);
samer@0: 	o=unfolder(@sfn1,state);
samer@0: 
samer@0: 	function [x,S]=sfn(S)
samer@0: 		x=X(:,S);
samer@0: 		S=1+mod(S,len);
samer@0: 	end
samer@0: 
samer@0: 	function [x,S]=sfn1(S)
samer@0: 		if S>len, error('ARROW:EOF','End of arrow sequence'); end
samer@0: 		x=X(:,S);
samer@0: 		S=S+1;
samer@0: 	end
samer@0: end