Re^3: How to import names from a dynamically required module

[tobyink]

in reply to Re^2: How to import names from a dynamically required module
in thread How to import names from a dynamically required module

This is not specific to import; it works with all class method calls...

use Math::BigInt;
my $class = "Math::BigInt";

my $six  = $class->new(6);
my $seven = "Math::BigInt"->new(7);
my $eight = join("::", "Math", "BigInt")->new(8);

In fact, string quoting class names is arguably a much better idea than the more conventional Math::BigInt->new(9), because the latter will start behaving surprisingly if there's ever a BigInt sub defined in the Math package.

[choroba]

string quoting class names is arguably a much better idea

Or, you can use Math::BigInt::->new(8).

[Anonymous Monk]

Or you can use Math::BigInt->new, because the odds of there being a BigInt sub in the Math package are astronomical :)

[tobyink]

The odds are small, yes. In my decade plus of Perl usage I've encountered bugs because of this two, perhaps three, times. But each time it took me bloody ages to figure out, which is why I have been trying to avoid this ambiguity in recent work.

The aliased module is, by the way, an excellent way of avoiding these problems:

use aliased 'Math::BigInt';

my $seven = BigInt->new(7);  # no ambiguity

[tobyink]

Indeed. This has the (often welcome) side-effect that the existence of the package is checked at compile-time, and a warning is issued (if warnings are enabled) if the package does not exist.

With stringy class names (and indeed with the traditional Foo::Bar->new) there is no such check, and Perl just blows up when it can't resolve the method call.