[Q]: How to include modules conditionally (using the pragma 'use')?

rbid has asked for the wisdom of the Perl Monks concerning the following question:

Hello,

Some of the scripts I'm writing depend on the hardware I have connected for some testing purposes.

Is there a way to have modules included according to a value of a variable?

    my $IS_MULTI_ICE_PRESENT = 1;
    my $IS_I2C_PRESENT = 0;
    ...
    use MyUtils:;MultiICE if ($IS_MULTI_ICE_PRESENT);
    use MyUtils:;I2C if ($IS_I2C_PRESENT);
    ...
[download]

I know that use is a pragma, therefore this code will not work.

What I want to do is like in "C":

    #define IS_MULTI_ICE_PRESENT 1
    #define IS_I2C_PRESENT       0
    ...
    #if IS_MULTI_ICE_PRESENT
    #include "multi_ice.h"
    #endif
    #if IS_I2C_PRESENT
    #include "i2c.h"
    #endif
    ...
[download]

Is this possible in Perl? (I guess that yes, but I don't know how to ... yet..)

Comment on [Q]: How to include modules conditionally (using the pragma 'use')? Select or Download Code

Replies are listed 'Best First'.
Re: [Q]: How to include modules conditionally (using the pragma 'use')? by cdarke (Prior) on Mar 08, 2010 at 11:44 UTC
Here is an example of using the if pragma: `use strict; use if ($^O eq 'MSWin32'), 'Win32::Process'; use if ($^O ne 'MSWin32'), 'POSIX'; use if ($^O ne 'MSWin32'), 'POSIX' => ':sys_wait_h'; # Hack to allow compilation under UNIX # (NORMAL_PRIORITY_CLASS is Win32 only) use if ($^O ne 'MSWin32'), 'constant' => 'NORMAL_PRIORITY_CLASS';` [download]	[reply] [d/l]
Re: [Q]: How to include modules conditionally (using the pragma 'use')? by Corion (Patriarch) on Mar 08, 2010 at 09:12 UTC
See use, or if, if you want something more fancy.	[reply]
Re: [Q]: How to include modules conditionally (using the pragma 'use')? by WizardOfUz (Friar) on Mar 08, 2010 at 09:11 UTC
`BEGIN { my $LOAD_FOO = 1; eval "use Foo; 1;" or die $@ if $LOAD_FOO; }` [download]	[reply] [d/l]