list=string2hist(cmd) %string2hist - convert a string of commands to a numerical list % list=string2hist(cmd) % F(ront),R(ight),U(p) are axes 1,2,3 on positive sides % B(ack),L(eft),D(own) are these axes on negative sides % a list is something lik

function list=string2hist(cmd)
%string2hist - convert a string of commands to a numerical list
%  list=string2hist(cmd)
%    F(ront),R(ight),U(p) are axes 1,2,3 on positive sides
%    B(ack),L(eft),D(own) are these axes on negative sides
%  a list is something like
%    FR2(UR)3, which means Front (clockwise (direction 1)), double right
%       three times the combination of Up and Right
%       ("'" can also be used for 3 rotates clockwise - or reverse)
%    the list may be ended with ".", after which all characters are not used

list=zeros(100,3);
iL=0;
S=cell(0,2);
cmd(end+1)='.';	% sentinel
iCmd=1;
while cmd(iCmd)~='.'
	axe=0;
	switch lower(cmd(iCmd))
	case 'f'
		axe=1;
		side=1;
	case 'r'
		axe=2;
		side=1;
	case 'u'
		axe=3;
		side=1;
	case 'b'
		axe=1;
		side=-1;
	case 'l'
		axe=2;
		side=-1;
	case 'd'
		axe=3;
		side=-1;
	case ''''
		if isempty(S)
			list(iL,3)=-list(iL,3);
		elseif S{end,2}	% still open
			S{end,1}(end,3)=-S{end,1}(end,3);
		else
			S{end,1}=S{end,1}(end:-1:1,:);
			S{end,1}(:,3)=-S{end,1}(:,3);
			[S,list,iL]=TestEnd(S,list,iL);
		end
	case {'1','2','3','4','5','6','7','8','9'}
		i=iCmd+1;
		while any(cmd(i)=='0123456789')
			i=i+1;
		end
		n=str2num(cmd(iCmd:i-1));
		if n>1
			if isempty(S)
				list(iL+1:iL+n-1,:)=list(iL+zeros(1,n-1),:);
				iL=iL+n-1;
			elseif S{end,2}	% still open
				m=size(S{end,1},1);
				S{end,1}(m+1:m+n-1,:)=S{end,1}(m+zeros(1,n-1),:);
			else
				S{end,1}=repmat(S{end,1},n,1);
				[S,list,iL]=TestEnd(S,list,iL);
			end
		end
		iCmd=i-1;
	case '('
		[S,list,iL]=TestEnd(S,list,iL);
		S{end+1,1}=zeros(0,3);
		S{end,2}=1;
	case ')'
		[S,list,iL]=TestEnd(S,list,iL);
		S{end,2}=0;
	case {' ',','}
		% doe niets
	otherwise
		error(sprintf('Unknown character in command list (''%c'')',cmd(iCmd)))
	end
	if axe
		[S,list,iL]=TestEnd(S,list,iL);
		if isempty(S)
			iL=iL+1;
			list(iL,1)=axe;
			list(iL,2)=side;
			list(iL,3)=1;
		else
			S{end,1}(end+1,:)=[axe side 1];
		end
	end
	iCmd=iCmd+1;
end
[S,list,iL]=TestEnd(S,list,iL);
if ~isempty(S)
	error('Not a correct command list')
end
list=list(1:iL,:);

function [S,list,iL]=TestEnd(S,list,iL)
if ~isempty(S)
	if S{end,2}==0
		if size(S,1)==1
			n1=size(S{end,1},1);
			list(iL+1:iL+n1,:)=S{end,1};
			iL=iL+n1;
		else
			S{end-1,1}=[S{end-1,1};S{end,1}];
		end
		S(end,:)=[];
	end
end