Course of Raku / Addendum 🆕 / Types and text machines / Regexes and grammars / Exercises

Validate identifiers

Problem

In many programming languages, a valid identifier starts with a letter or underscore and continues with letters, digits, or underscores. For count, total2, 2fast, my-var, and _hidden, print whether each is a valid identifier by that classic rule.

(Raku itself is more generous: my-var is a perfectly valid Raku identifier. Check the solution page for that variant too.)

Example

The program prints:

count: valid
total2: valid
2fast: invalid
my-var: invalid
_hidden: valid

Solution

✅ See the solution

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