Documentation for method placeholder assembled from the following pages:
Class: X::Placeholder::Block §
(X::Placeholder::Block) method placeholder §
Returns the name of the (first) illegally used placeholder.
Class: X::Signature::Placeholder §
From X::Signature::Placeholder
(X::Signature::Placeholder) method placeholder §
method placeholder(--> Str)Returns the name of a placeholder that was used in a block that already had a signature.