scan:
	proc(n);
	%replace
		true  by '1'b,
		false by '0'b;
	dcl
		n fixed,
		accum char (128) var external,
		line  char (128) var static init('');
	dcl
		c char(1),
		i fixed;

	tracer:
		proc;
		put edit(n,' scan: ',accum) (skip,f(3),2a);
		end;

		do while(true);
		if length(line) = 0 then
			get edit(line) (a);
		else
			line = substr(line,length(accum)+1);
		i = verify(line,' ');
		if i = 0 then
			line = '';
		else
			do;
			line = substr(line,i);
			accum = substr(line,1,1);
			if index('[]->;().,"',accum) ~= 0 then
				do;
				call tracer();
				return;
				end;
				do i = 2 to length(line);
				c = substr(line,i,1);
				if index(' []->;().,"',c) ~= 0 then
					do;
					accum = substr(line,1,i-1);
					if c ~= '.' then
						do;
						call tracer();
						return;
						end;
					if verify(accum,'0123456789') ~= 0 then
						do;
						call tracer();
						return;
						end;
					end;
				end;
			accum = line;
			do;
			call tracer();
			return;
			end;
			end;
		end;
	call tracer();
	end scan;