samer@0: % arr - Lift function to processing unit
samer@0: %
samer@0: % arr :: 
samer@27: %    F:(A@typelist(N)->B@typelist(M)) ~'arbitrary function with N inputs and M outputs',
samer@0: %    options { 
samer@0: %       nargin  :: natural / nargin(F);
samer@0: %       nargout :: natural / nargout(F);
samer@0: %    }
samer@27: % -> arrow(A@typelist(N),B@typelist(M),empty).
samer@0: %
samer@0: % The arr class is a class of arrows which simply apply an ordinary
samer@0: % Matlab function to the inputs to obtain the outputs. In many cases,
samer@0: % the number of inputs and outputs can be determined from the supplied
samer@0: % function handle, but if the number arguments in or out is variable,
samer@0: % then the nargin and nargout options must be used.
samer@0: %
samer@0: % The type empty denotes the type of empty arrays, ie
samer@0: % the state of an arr arrow is always an empty matrix.
samer@0: %
samer@0: % arr(@log) - arrow which supplies the log of its input.
samer@0: % arr(@plus) - sum two inputs to produce output
samer@0: % arr(@(a,b)deal(a+b,a-b),'nargout',2) - computes sum and difference of inputs.
samer@0: 
samer@0: function o=arr(fn,varargin)
samer@0: 	if nargin==0, fn=@id; end
samer@37: 	opts=options('nargin',[],'nargout',[],'sizefn',[],varargin{:});
samer@0: 	if isempty(opts.nargin), opts.nargin=nargin(fn); end
samer@0: 	if isempty(opts.nargout), opts.nargout=nargout(fn); end
samer@0: 	if opts.nargout<0, opts.nargout=1; end % assume 1 if we can't tell
samer@0: 	o=class(struct('fn',fn,'sizefn',opts.sizefn),'arr',arrow(opts.nargin,opts.nargout));
samer@0: end