Re^2: unless weirdness

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Re^3: unless weirdness by CountZero (Bishop) on May 08, 2009 at 06:07 UTC
In that case you must call your sub as follows : `check_disk_space()` [download] From `perldoc perlsub`: A subroutine may be called using an explicit & prefix. The & is optional in modern Perl, as are parentheses if the subroutine has been predeclared. CountZero A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James	[reply] [d/l] [select]
Re^4: unless weirdness by ikegami (Patriarch) on May 08, 2009 at 06:34 UTC
That quote is misleading. "&" has side-effects. It's purpose isn't to get around declaring a sub.	[reply]
Re^5: unless weirdness by chromatic (Archbishop) on May 08, 2009 at 08:43 UTC
Its purpose isn't to get around declaring a sub. Yes and no. It's an unambiguous parser hint that the following potential bareword isn't a bareword but a subroutine call. I hate it too, but that's one of its functions.	[reply]
Re^4: unless weirdness by Plankton (Vicar) on May 08, 2009 at 21:02 UTC
Why doesn't that apply to ... `die "Not enough disk space.\n" if check_disk_space;` [download] ... ?	[reply] [d/l]
Re^3: unless weirdness by wfsp (Abbot) on May 08, 2009 at 06:13 UTC
Doing it that way both `if` and `unless` will fail. If you don't declare the sub up front you need to call the sub with parens: `check_disk_space()`. There is some weirdness though. With `if` the error is `Bareword "check_disk_space" not allowed while "strict subs" in use...` [download] and with `unless` `Bareword "check_disk_space" not allowed while "strict subs" in use... Bareword "check_disk_space" not allowed while "strict subs" in use...` [download] Not sure why it comes up twice. I prefer to have all my subs at the end of the script and always call them with the parens. I use parens with perl built ins too if the args have any level of complexity. YMMV.	[reply] [d/l] [select]