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Class#defining and #redefining metaprogramming methods
- Docs: http://sixarm.com/sixarm_ruby_defining/doc
- Repo: http://github.com/sixarm/sixarm_ruby_defining
- Email: Joel Parker Henderson, firstname.lastname@example.org
Meta-programming method that we call when we are defining (or redefining) a class method, to detect if we're accidentally overriding an existing method.
- Suppose we're creating a class defining a method named "foo".
- Before we do it, we want to check to see if the method "foo" already exists, so we don't accidentally override it.
- We call #defining which asks if the method "foo" already exists then gives us feedback if we can proceed safely.
- We call #redefining if we know the method already exists and we are overriding it/
Example of defining a new method:
class C defining "foo" #=> return true; it's safe to proceed because #foo is not defined.
Example of error detection:
class C defining "hash" #=> raise an error; it's not safe to proceed because #hash is already defined.
Example of intentionally overriding an existing method:
class C redefining "hash" #=> return true; it's safe to proceed because #hash is already defined.
Example of error detection:
class C redefining "foo" #=> raise an error; it's not safe to proceed because #foo is not yet defined.
For docs go to http://sixarm.com/sixarm_ruby_defining/doc
Want to help? We're happy to get pull requests.
gem install sixarm_ruby_defining
gem "sixarm_ruby_defining", "=1.1.0"
Install with high security (optional)
To enable high security for all our gems:
wget http://sixarm.com/sixarm.pem gem cert --add sixarm.pem gem sources --add http://sixarm.com
To install with high security:
gem install sixarm_ruby_defining --test --trust-policy HighSecurity
Multiple method names
The methods can take multiple names.
Example of #defining multiple names:
class C defining "foo", "goo", "hoo" #=> return true if we're safe i.e. all the methods are not yet defined, #=> otherwise raise an error for each method that is already defined.
Example of #redefining multiple names:
class C redefining "hash", "inspect", "equal?" #=> return true if all the methods are already defined, #=> otherwise raise an error for each method that is not yet defined.
We can intermix the methods however we like:
class C ... defining "foo", "goo" ... redefining "hash", "inspect" ... defining "goo" ... redefining "equals?"
Customization for success and failure
For meta-programming we can customize what happens when #defining and #redefining encounter methods that are
defining_success: called by #defining when a method name is not yet defined; this will return true.
defining_failure: called by #defining when a method name is already defined; tihs will raise an error.
redefining_success: called by #redefining when a method name is already defined; this will return true.
redefining_failure: called by #redefining when a method name is not yet defined; tihs will raise an error.
- 2012-03-17 1.1.0 Upgrade for Ruby 1.9.3, minitest/spec, and improved docs.
- 2011-10-08 1.0.6 Updates for gem publishing
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Copyright (c) 2005-2012 Joel Parker Henderson