Course of Raku / Advanced / Modules / Packages and namespaces 🆕 / Exercises / A package

Solution: A package

Here is a possible solution to the task.

Code

package Temperature {
    our $freezing = 0;
    our sub fahrenheit($c) { $c * 9/5 + 32 }
}

say $Temperature::freezing;
say Temperature::fahrenheit(100);

🦋 You can find the source code in the file a-package.raku.

Output

0
212

Comments

  1. Both the variable and the subroutine are declared with our, so both become part of the Temperature namespace and are reachable from outside.

  2. The variable is reached as $Temperature::freezing — sigil, package name, then variable name — while the subroutine is called as Temperature::fahrenheit(100). Converting 100 gives 100 * 9/5 + 32, which is 212.

  3. A plain package provides just the namespace. For a reusable library we would have used module instead — and, once objects are on the table, a class — but the namespace mechanism is the same in each case.

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