Editing JOSS (section)

====Do====
{{code|Do}} is similar to {{code|To}}, but branches to a subroutine. As with {{code|To}}, you can {{code|Do part}} or {{code|Do step}}. If a step is provided, that single line is run and then returns to the statement after the {{code|Do}}. If a part is provided, execution starts at the first line of the block and continues until the end of the block is reached or a {{code|Done}} statement is encountered.
 01.15 Do step 7.24.
 01.16 Do part 8.

{{code|Do}} had one special short form for looking in keeping with it being very common in most programs. This used the {{code|times}} modifier instead of a normal {{code|for}}, in the case for simple loops. So the following lines are equivalent:{{sfn|Gimble|1967|p=66}}

 Do part 1 for i=1(1)5.
 Do part 1, 5 times.

JOSS maintains a pointer to the currently executing line, which a {{code|Do}} would change. However, it included a special "parenthetic do" that could be used in direct mode to test certain sections of the code without changing the main pointer. For instance, if the program stopped due to an error and it was not clear which section caused the problem, one might test a particular subroutine with:{{sfn|Gimble|1967|p=58}}

  (Do part 2.)