it(ch) or else ch = '_' loop
				if k <= 10 then
					id(k) := upper(ch);
					k := k + 1;
				end if;
				declare
					och : character := ch;
				begin
					next_ch;
					if och = '_' then
						if not letter_or_digit(ch) then
							error(1,line_count);
							exit;
						end if;
					end if;
				end;
			end loop;

			-- perform binary search for reserved word
			
			h := symbol'pos(abort_sy); j := symbol'pos(xor_sy);
			loop
				k := (h+j)/2;
				if id <= word(symbol'val(k)) then
					j := k - 1;
				end if;
				if id >= word(symbol'val(k)) then
					h := k + 1;
				end if;
				exit when h > j;
			end loop;
			if h - 1 > j then
				token := symbol'val(k);
			else
				token := identifier;
			end if;

		elsif digit(ch) then
			number_cruncher:
			declare
				base : integer := 10;	-- fefault base is decimal
				i : integer;		-- integer converted from last character
				exponent : integer;
				based_ch : character;	-- # or :

				function in_base(ch : character) return boolean is
				begin
					if digit(ch) then
						i := character'pos(ch) - character'pos('0');
					elsif hex(ch) then
						i := character'pos(ch) - character'pos('A') + 10;
					else
						return false;
					end if;
					if i < base then
						return true;
					else
						return false;
					end if;
				end in_base;

				function get_integer return integer is
					num : integer := 0;
				begin
					while in_base(ch) loop
						num := num * base + i;
						next_ch;
						if ch = '_' then
							next_ch;
							if not in_base(ch) then
								error(3,line_count);
							end if;
						end if;
					end loop;
					return num;
				end get_integer;

				function get_fraction return float is
					num : float := 0.0;
					divi : float := 1.0 / float(base);
				begin
					while in_base(ch) loop
						num := num + float(i) * divi;
						divi := divi / float(base);
						next_ch;
						if ch = '_' then
							next_ch;
							if not in_base(ch) then
								error(3,line_coun