perl6/doc/lib/Exception
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Those closure are of type L<WhateverCode>.
Not all operators and syntactic constructs curry Whatever-stars.
(title) class Exception
class Exception { ... }
All exceptions that are placed into the $! variable (or into $_
in CATCH blocks) inherit from Exception . When you call die
or fail with a non-Exception argument, it is wrapped into an
X::AdHoc object, which also inherits from Exception .
User-defined exception classes should inherit from Exception too, and
define at least a method message .
class X::YourApp::SomeError is Exception {
method message() {
"A YourApp-Specific error occurred: out of coffee!";
}
}
Methods
(head2) message
method message(Exception:D:) returns Str:D
This is a stub that must be overwritten by subclasses, and should
return the exception message.
Special care should be taken that this method does not produce
an exception itself.
(head2) backtrace
method backtrace(Exception:D:) returns Backtrace:D
Returns the backtrace associated with the exception. Only makes sense
on exceptions that have been thrown at least once.
(head2) throw
method throw(Exception:D:)
Throws the exception.
(head2) rethrow
method rethrow(Exception:D:)
Rethrows an exception that has already been thrown at least once.
This is different from throw in that it preserves the original
backtrace.
(head2) fail
method fail(Exception:D:)
Same as fail $exception ; i.e., it exits the calling Routine
and returns the exception wrapped in a L<Failure> object.
(head2) gist
multi method gist(Exception:D:)
Returns whatever the exception printer should produce for this exception.
The default implementation returns message and backtrace separated by
a newline.
