Rules / Types, classes & roles / exception

X::Parameter::Default Reference

Compilation error due to an unallowed default value in a signature

What it is #

Routines #

Signatures are reproduced from the documentation, including their declared return types. A routine listed here is part of the type's published interface; whether Raku++ implements it is a separate question, answered by the examples below.

method how #

Returns a string describing how the parameter is qualified that makes it disallow default values, for example "slurpy" or "mandatory".

method parameter #

Returns the parameter name

Examples, run three ways #

Every example below comes from the official documentation, together with the output that documentation asserts. Each was then executed by Rakudo and by Raku++ when this page was built. Where the three agree, one result is shown; where they do not, all three are — because which of them is wrong is exactly the information worth having.

5 no-output

class X::Parameter::Default does X::Comp { }

Not executed: the documentation states no expected output for this example.

sub f($x! = 3) { }

Not executed: the documentation states no expected output for this example.

Cannot put default on required parameter $x

Not executed: the documentation states no expected output for this example.

sub f(*@ = 3) { }

Not executed: the documentation states no expected output for this example.

Cannot put default on anonymous slurpy parameter

Not executed: the documentation states no expected output for this example.