GOTO

  The goto statement is used to branch (jump) from one place to an-
  other, within a function. The use of goto statements is considered
  bad style. They can make code very hard to understand, and are in
  fact almost never necessary. For example, Telix is written mainly in
  the C language, which has a goto statement, yet except for a few
  pieces of pre-written code, the goto statement was never used nor
  needed. On the other hand, used very sparingly and properly, it can
  sometimes make some code clearer and perhaps faster. The goto state-
  ment consists of two parts, the 'label' or marker, which is where
  execution will jump to, and the actual goto itself. A label is de-
  fined in the form

       <identifier>:

  where <identifier> follows the same rules as for variable names.
  Note that a colon follows the name, not a semicolon. The colon char-
  acter must immediately follow the label name, with no intervening
  spaces. A label does not have to be on a line by itself, and is not
  considered a statement by itself. The goto takes the form

       goto <label>;

  where <label> is a label elsewhere in the function defined as de-
  scribed above. Execution of the script will immediately continue
  following the label.

  An example is:

       start:
       prints("Hello");
       goto start;

  This would print the word "hello" over and over, forever. There is
  no restriction on the placement of a label, so the above can be
  written as:

       start: prints("Hello");
       goto start;

  As mentioned above, there are usually better ways than using a goto
  statement. For example:

       int i = 0;
       do
        i = i + 1;
       while (i < 100);

  is clearer than the equivalent:

       int i = 0;
       loop:
        i = i + 1;
        if (i < 100)
         goto loop;

  One good use of a goto statement is to get out of a deeply nested
  while statements, without having to do a lot of extra checking.