The Ruby VM could not be set up.

An object has the wrong type for an operation.

Raised for example when setting a CVar on a non-class object.

A value passed to the library is out of range for some reason.

Raised for example when declaring a method with fixed arity > 15.

An identifier looks to be spelt wrong.

Raised for example when an IVar name does not begin with ‘@’.

A keyword argument is duplicated.

Raised when a kwArgs parameter is passed and the list contains duplicate argument keywords.

A Ruby exception occurred.

You are free to ignore or handle this error. If your code has been invoked from Ruby then you can also re-throw the error to pass it back down the stack.

Some Ruby flow control has happened.

Raised when you invoke a block from Swift and the block does return or break. You must do any Swift-side cleanup and re-throw the error without talking to Ruby, otherwise the Ruby runtime will become confused at best.

Holds the most recent errors thrown by RubyGateway.

This can be useful when the module indicates an error has occurred through a nil result somewhere – the error causing the nil has still been generated internally and is stashed here.

These nil results happen during type conversion to Swift, for example String.init(_:), and when using the RbObjectAccess.failable adapter that suppresses throwing.

Methods are thread-safe.

A short history of errors thrown by RubyGateway

A human-readable description of the error.