samer@36: % resizer - sequence with overridden reported element size
samer@3: %
samer@36: % resizer :: Size:[[1,E]], seq([_->A]) -> seq([Size->A]).
samer@36: classdef resizer < seq
samer@3: 	properties (GetAccess=private, SetAccess=private)
samer@3: 		source
samer@3: 		newsize
samer@3: 		check
samer@3: 	end
samer@3: 	methods
samer@36: 		function o=resizer(newsize,source,check)
samer@3: 			if ~size_match(elsize(source),newsize),
samer@36: 				error('seq.resizer: size mismatch');
samer@3: 			end
samer@3: 			if nargin<3, check=0; end
samer@3: 			o.source=source; 
samer@3: 			o.newsize=newsize;
samer@3: 			o.check=check;
samer@3: 		end
samer@3: 
samer@3: 		function x=head(a), x=head(a.source); if a.check, size_check(a.newsize,size(x)); end; end
samer@23: 		function d=next(d), d.source=next(d.source); if isempty(d.source), d=nil; end; end
samer@3: 		function s=elsize(a), s=a.newsize; end
samer@3: 		function s=tostring(a), s=tostring(a.source); end
samer@3: 	end
samer@3: end
samer@3: 
samer@3: function b=size_match(s1,s2)
samer@3: 	b=all((s1==s2) | isnan(s1) | isnan(s2));
samer@3: end
samer@3: 
samer@3: function b=size_check(spec,size)
samer@3: 	if ~all((spec==size) | isnan(spec))
samer@36: 		error('seq.resizer: element size does not match specification');
samer@3: 	end
samer@3: end