A break statement can only occur inside a for or while loop. When it is encountered, it causes the termination only of the innermost enclosing loop.
You could potentially have a loop inside of a_file but break inside that file would terminate only that loop and not the function a_file itself.
To have function a_file terminate a loop in its calling function or script, there are two possibilities:
- function a_file could use error to force abornal termination of function a_file . Calling functions up the call chain would also be terminated, until you either got back to the command line or else got to a level that was executing inside a try, catch block. This is technically valid programming, but unless the condition represents some actual error or unhandled condition, it is often not considered good programming style. (I have heard, though, that there is a school of programming that says that you should use throwing errors and catching errors routinely; the claim is something along the lines that throwing an error allows you to construct more compact code than nested if/else chains to handle the combinations of errors that can occur.)
- you can have a_file return a value that indicates whether it is asking the caller to terminate the current loop; if so then the calling function would break or as appropriate to end its section. This is generally considered better program structure.
