Feature comparison between Perl function signature implementations

As the author of one of these, I am arguably biased, so a diligent reader may wish to check the documentation of the relevent modules, and perform their own benchmarking.

Feature comparison between Perl function signature implementations
Feature Function-Parameters Kavorka Method-Signatures MooseX-Method-Signatures
Positional parameters Yes Yes Yes Yes
Named parameters Yes Yes Yes Yes
Long named parameters No Yes No No
Slurpy parameters Yes Yes Yes Yes
Required parameters Yes Yes Yes Yes
Optional parameters Yes Yes Yes Yes
Aliased parameters No Yes Yes No
Defaults for optional parameters Yes Yes Yes Yes
Fine-grained control over when defaults are used No Partial (provides //= and ||=) Yes No
Type constraints Yes Yes Yes Yes
Type coercion No Yes Yes Yes
Value constraints No Yes Yes Yes
Return type constraints No Yes No Yes
Return type coercion No Yes No No
Allows $_ to be used as a parameter No Yes No No
Allows \@foo to be used as a parameter No Yes Yes No
Can define non-method functions Yes Yes Yes No
Method modifiers No Yes Yes Yes
Multi methods / multi subs No Yes No Requires extension (requires MooseX-MultiMethods)
Anonymous functions / methods Yes Yes Yes Yes
Lexical (private) functions / methods Sort of (you can assign an anonymous function/method to a lexical variable) Yes Sort of (you can assign an anonymous function/method to a lexical variable) Sort of (you can assign an anonymous function/method to a lexical variable)
Prototypes (like (&@)) Yes Yes No No
Attributes (like :lvalue) Yes Yes No No
Introspection API Yes Yes No Yes
Extensible in Pure Perl No Yes Yes Yes
Benchmarking results, with Moose 9732/s 17598/s 8980/s 777/s
Benchmarking results, with Mouse 10353/s 43689/s 41684/s 817/s
Minimum Perl version 5.14.0 5.14.0 5.8.8 5.8.6
Non-core dependencies 3 38 40 78