Course of Raku / Advanced / Modules / Modules basics

Importing

There is more than one way to bring a module into a program. The three statements use, need, and require differ in when the module is loaded and in what it makes available.

use

You have already met use. It loads the module at compile time and imports its exported names, so they can be called directly:

use Greeting;
say hello('Anna'); # Hello, Anna!

need

need also loads the module at compile time, but it does not import the exported names. You still reach the module’s our variables through the module’s name:

need Greeting;
say $Greeting::version; # 1.0

After need Greeting, a bare hello(...) would not be recognised, because nothing was imported — only the qualified names, such as $Greeting::version, are available.

require

require loads the module at run time rather than at compile time. This is useful when you do not know until the program runs whether a module will be needed, for example when its name is decided by user input.

Because the loading happens at run time, nothing is imported automatically. Listing the symbols you want in angle brackets after the name pulls them in, so they can be called directly:

require Greeting <&hello>;
say hello('Anna'); # Hello, Anna!

For everyday use, use is what you want; need and require are there for the less common cases.

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