In Str§

See primary documentation in context for routine tc

multi        tc(Str:D  --> Str:D)
multi method tc(Str:D: --> Str:D)

Does a Unicode "titlecase" operation, that is changes the first character in the string to title case, or to upper case if the character has no title case mapping

In Cool§

See primary documentation in context for routine tc

sub tc(Str(Cool))
method tc()

Coerces the invocant (or in sub form, its argument) to Str, and returns it with the first letter case-folded to title case (or where not available, upper case).

say "abC".tc;       # OUTPUT: «AbC␤»

In Allomorph§

See primary documentation in context for method tc

method tc(Allomorph:D:)

Calls Str.tc on the invocant's Str value.