function varargout = cacheFunction(varargin)
% cacheFunction(functionHandle,arg1,arg2,...)
% cacheFunction will evaluate the functionHandle with the arguments that
% follow it, and will store the output in a global variable
% (functionCache), the output will be reused if the same function is called
% with the same input arguments.

cacheSize = 100;

global functionCache;

if isempty(functionCache)
    functionCache = {};
end

funchandle = varargin{1};

for n = 1:size(functionCache, 1)
    cachedVarargin = functionCache{n, 1};
    cachedVarargout = functionCache{n, 2};
    if numel(cachedVarargin) ~= nargin || numel(cachedVarargout) ~= max(nargout,1)
        continue;
    elseif ~all(cellfun(@isequaln, cachedVarargin, varargin))
        continue;
    end
    
    disp(['Reusing results of ' func2str(funchandle) ' from a previous run (cached in the global variable ''functionCache'')']);
    varargout = cachedVarargout;
    % reorder cache to reflect the recent use of this item
    idx = [1:n-1 n+1:size(functionCache, 1) n];
    functionCache = functionCache(idx, :);
    return;
end

% this trick for wrapping a varargin/varargout function comes from:
% http://stackoverflow.com/questions/4895556/how-to-wrap-a-function-using-varargin-and-varargout
[varargout{1:nargout}] = funchandle(varargin{2:end});

functionCache{end+1, 1} = varargin;
functionCache{end, 2} = varargout;
functionCache = functionCache(max(end-cacheSize+1, 1):end, :);

end