From type/Allomorph

See Original text in context

method fc(Allomorph:D:)

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

From type/Cool

See Original text in context

sub fc(Str(Cool))
method fc()

Coerces the invocant (or in sub form, its argument) to Str, and returns the result a Unicode "case fold" operation suitable for doing caseless string comparisons. (In general, the returned string is unlikely to be useful for any purpose other than comparison.)

say "groß".fc;       # OUTPUT: «gross␤»

From type/Str

See Original text in context

multi sub    fc(Str:D  --> Str:D)
multi method fc(Str:D: --> Str:D)

Does a Unicode "fold case" operation suitable for doing caseless string comparisons. (In general, the returned string is unlikely to be useful for any purpose other than comparison.)