perl6/doc/lib/X/Parameter/Default
doc src
(title) class X::Parameter::Default
class X::Parameter::Default does X::Comp { }
Compile-time error thrown when a parameter in a signature has default value,
but isn't allowed to have one. That is the case with slurpy parameters
(because a slurpy always binds successfully, even to zero arguments)
and with mandatory parameters.
Example:
sub f($x! = 3) { }
Produces
===SORRY!===
Cannot put default on required parameter $x
And
sub f(*@ = 3) { }
produces
Cannot put default on anonymous slurpy parameter
Methods
(head2) how
Returns a string describing how the parameter is qualified that makes
it disallow default values, for example "slurpy" or "mandatory" .
(head2) parameter
Returns the parameter name
