Ruby Exception Hierarchy

The class hierarchy we just made a custom exception by subclassing standarderror which itself subclasses exception.

Ruby exception hierarchy. The reason for this is that while all ruby exceptions and errors are an extension of the exception class many of them are reserved for use internally by ruby. This includes both code snippets embedded in the card text and code that is included as a file attachment. While it may be tempting to rescue every child of the exception class it is generally considered bad practice due to the way the ruby exception hierarchy is structured. Excepted from this license are code snippets that are explicitely marked as citations from another source.

The match will succeed if the exception named in the rescue clause is the same as the type of the currently thrown exception or is a superclass of that exception. Understanding the ruby exception hierarchy exceptions are just classes in ruby. Ruby contains a predefined hierarchy of exceptions as shown below. In the above diagram most of the exceptions come under standarderror class which are the general exceptions arises in the ruby program.

All source code included in the card ruby exception class hierarchy is licensed under the license stated below. Here i ll prove it to you. At the top most level of the exception class hierarchy resides the exception class the monolithic parent class of over a half dozen subclasses which typically regulate the grunt work of ruby exception handling. Ruby features a plethora of built in classes to dramatically simplify exception handling and management.

In fact if you look at the class hierarchy of any exception in ruby you ll find it eventually leads back to exception. For each rescue clause in the begin block ruby compares the raised exception against each of the parameters in turn. Ruby s exception class exception is the top level class in ruby that all errors inherit from. The exception exception hierarchy is made up of all the classes that inherit from exception.

Pickaxe 2nd ed page 462. Here s a the exception hierarchy for ruby 2 1 s standard library. Today i needed to know the class hierarchy under exception and maybe it s there online but i couldn t find it. Well you could always use ruby itself too that way you ll always have an up to date list.