samer@0: % delay - arrow implementing a delay line
samer@0: %
samer@0: % delay ::
samer@0: %    W:natural   ~'width of buffer',
samer@0: %    A           ~'a value to pad delay line with'
samer@0: % -> arrow({[[N,1]->A]}, {[[N,1]->A]}, {[W]->[[N]->A]}).
samer@0: 
samer@0: function a=delay(n,pad)
samer@0: 	a=loop(@delayfn,@(sz)repmat({repmat(pad,sz)},1,n));
samer@0: 	function [out,buf]=delayfn(in,buf)
samer@0: 		out=buf{1};
samer@0: 		buf=[buf(2:end),{in}];
samer@0: 	end
samer@0: end