Re: Conditionally faking a module

If you want to run some code if a module isn't installed, just test the use statement for failure:

eval "use Cava::Pack" 
 or do { 
  # your code goes here
};
[download]

Super Search will find several threads on this topic, including Auto install of a perl package if 'use' statement fails.

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Re^2: Conditionally faking a module by wanna_code_perl (Friar) on Jan 13, 2010 at 19:01 UTC
Unfortunately, your example doesn't work: `eval "use Cava::Pack" or do { die "Using faked out Cava::Pack\n"; }` [download] I see the "Using faked out Cava::Pack" message on both Linux and Win32 (where Cava::Pack is indeed available).	[reply] [d/l]
Re^3: Conditionally faking a module by bobf (Monsignor) on Jan 13, 2010 at 19:14 UTC
Apparently it may not always work, as I learned when I researched this further (see RE: Checking to see if a particular Module is installed). merlyn's response was to use the following: `eval 'require GD'; if ($@) { # problems with GD, fall back to non-GD } else { # we have GD, go for it! }` [download] although there appears to be some caveats to that approach. If you are open to using other modules to do the check, you could look into ExtUtils::Installed and Module::Load::Conditional. See also a recent thread on this topic: Check if module is installed.	[reply] [d/l]
Re^3: Conditionally faking a module by Anonymous Monk on Jan 13, 2010 at 21:27 UTC
That is the reason for a true value, 1 `eval "use Cava::Pack; 1" or die "Oh noes! $@"; eval "use HOW::Cava::Pack; 1" or die "HOW!?! $@"; __END__ HOW!?! Can't locate HOW/Cava/Pack.pm in @INC (@INC contains: C:/perl/5 +.10.1/lib/MSWin32-x86-multi-thread C:/perl/5.10.1/lib C:/perl/site/5. +10.1/lib/MSWin32-x86-multi-thread C:/perl/site/5.10.1/lib .) at (eval + 2) line 1. BEGIN failed--compilation aborted at (eval 2) line 1.` [download] Hmm, I don't recall installing Cava::Pack :)	[reply] [d/l]
Re^3: Conditionally faking a module by ikegami (Patriarch) on Jan 15, 2010 at 18:01 UTC
The code being executed by `eval` (`""`) returns nothing (`()`), which is indistinguishable from the value `eval` returns on failure. You need `eval "use Cava::Pack; 1"` [download]	[reply] [d/l] [select]


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