Mixin Names: dash character and underscore character seem to be treated as equals

[tbremer]

See the sassmeister link for a working example.

But essentially, these are treated as equals:

@mixin under_score {
  content: 'under_score';
}

html {
  @include under_score;
  @include under-score;
}

Is this purposeful?

[Snugug]

Yes, underscores and dashes are treated the same in both function and mixin names.

[stephnr]

👍 very interesting find

[nex3]

Yes, this is purposeful. Back before 3.0, only underscores were allowed in identifiers. When we added support for hyphens to match CSS's syntax, we wanted it to be possible for code to remain compatible by continuing to use underscores but still be callable in the new, nicer-looking syntax so we made them equivalent.