Do you know how to define ##method_names class variable so that both my_macro and invoke_methods can use it as intended? Thank you!
module MyModule
module ClassMethods
def my_macro method_name, options = { }
define_method method_name do
puts "defining #{method_name} with #{options}"
end
##method_names << method_name
end
end
def invoke_methods
##method_names.each { |method_name| send method_name }
end
def self.included includer
includer.extend ClassMethods
end
end
class MyClass
include MyModule
my_macro :method_foo, :bar => 5
my_macro :method_baz, :wee => [3,4]
end
MyClass.new.invoke_methods
Here's a working version. Changes are commented:
module MyModule
module ClassMethods
##method_names ||= [] #move this up here
def my_macro method_name, options = { }
define_method method_name do
puts "defining #{method_name} with #{options}"
end
##method_names << method_name
end
#added this (rename as required)
def the_methods
##method_names
end
end
def invoke_methods
#changed this call
self.class.the_methods.each { |method_name| send method_name }
end
def self.included includer
includer.extend ClassMethods
end
end
class MyClass
include MyModule
my_macro :method_foo, :bar => 5
my_macro :method_baz, :wee => [3,4]
end
MyClass.new.invoke_methods
module MyModule
module ClassMethods
def my_macro method_name, options = { }
define_method method_name do
puts "defining #{method_name} with #{options}"
end
#method_names ||= []
#method_names << method_name
end
def method_names
#method_names
end
end
def invoke_methods
self.class.method_names.each { |method_name| send method_name }
end
def self.included includer
includer.extend ClassMethods
end
end
class MyClass
include MyModule
my_macro :method_foo, :bar => 5
my_macro :method_baz, :wee => [3,4]
end
MyClass.new.invoke_methods
Related
I know there is should be a way to initialize class instance variable that added by a module via extend
example:
module MyModule
def self.included(base)
base.extend ClassMethods
base.send :include, InstanceMethods
end
module ClassMethods
attr_accessor :count
def self.count
#count = 0
end
count
end
module InstanceMethods
def register
# self.class.count = 0 if self.class.count.nil?
self.class.count += 1
end
end
end
class Foo
include MyModule
private
def initialize
register
end
end
In ClassMethods should be a way to initialize count, but i always catch error "undefined method `+' for nil:NilClass"
When i perform
f = Foo.new
No problem in module InstanceMethods if i uncomment line
# self.class.count = 0 if self.class.count.nil?
Work correctly!
You could move the variable initialization into the included callback:
module MyModule
def self.included(base)
base.extend ClassMethods
base.include InstanceMethods
base.count = 0
end
module ClassMethods
attr_accessor :count
end
module InstanceMethods
def register
self.class.count += 1
end
end
end
One bit too many self in your code. You already extend your ClassMethods module. extend uses instance methods, not class methods. So your module should look like this (rest of the code unchanged).
module ClassMethods
def count
#count ||= 0
end
attr_writer :count
end
Then it works
Foo.count # => 0
Foo.new
Foo.count # => 1
This my implementation to developing way to run code before all method in your model
The call "before_hook :months_used" method need to be on bottom of class to the ExecutionHooks can get the instance_method loaded in the module. I would like to load the instance methods on top
class BalanceChart < BalanceFind
include ExecutionHooks
attr_reader :options
def initialize(options = {})
#options = options
#begin_at = #options[:begin_at]
end
def months_used
range.map{|date| I18n.l date, format: :month_year}.uniq!
end
before_hook :months_used
end
module ExecutionHooks
def self.included(base)
base.send :extend, ClassMethods
end
module ClassMethods
def before
#hooks.each do |name|
m = instance_method(name)
define_method(name) do |*args, &block|
return if #begin_at.blank? ## the code you can execute before methods
m.bind(self).(*args, &block) ## your old code in the method of the class
end
end
end
def before_hook(*method_name)
#hooks = method_name
before
end
def hooks
#hooks ||= []
end
end
end
You can do this with prepend. prepend is like include in that it adds a module to the ancestors of the class, however instead of adding it after the class it adds it before.
This means that if a method exists both in the prepended module and the class then the module implementation is called first (and it can optionally call super if it wants to call the base class).
This allows you to write a hooks module like so:
module Hooks
def before(*method_names)
to_prepend = Module.new do
method_names.each do |name|
define_method(name) do |*args, &block|
puts "before #{name}"
super(*args,&block)
end
end
end
prepend to_prepend
end
end
class Example
extend Hooks
before :foo, :bar
def foo
puts "in foo"
end
def bar
puts "in bar"
end
end
In real use you would probably want to stash that module somewhere so that each call to before doesn't create a new module but that is just an inplementation detail
#rathrio This is my implementation using method_added that you talked. Thanks
module ExecutionHooks
def validation
p "works1"
end
def self.included(base)
base.send :extend, ClassMethods
end
end
module ClassMethods
attr_writer :hooked
def hooked
#hooked ||= []
end
def method_added(method)
return if #hooks.nil?
return unless #hooks.include?(method)
m = self.instance_method(method)
unless hooked.include?(method)
hooked << method
define_method(method) do |*args, &block|
validation
m.bind(self).(*args, &block) ## your old code in the method of the class
end
end
end
def before_hook(*method_name)
#hooks = method_name
end
def hooks
#hooks ||= []
end
end
end
class BalanceChart < BalanceFind
include ExecutionHooks
before_hook :months_data, :months_used, :debits_amount, :test
def test
"test"
end
end
Instead of redefining the method when calling before_hook, you could override the method_added hook to prepend your before hooks to a method right after it was defined. This way your before_hook calls can be (actually, must be) placed at the top of the class definition.
Having a hard time figuring this out. Suppose I wanted to write a module, and when included, it would allow classes to define methods by calling a method with symbols
class Anything
include Foo
initializers :hello, :goodbye
end
module Foo
# What goes in here? Its not
# def self.initializers(*symbols)
end
Same syntax idea as attr_accessible. Tried finding it in the Rails source, but, well..
module Foo
def self.included(base)
base.extend ClassMethods
end
module ClassMethods
def initializers *names
names.each do |name|
define_method name do
'ok'
end
end
end
end
def self.included(base)
base.extend ClassMethods
end
end
class Anything
include Foo
initializers :hello, :goodbye
end
puts Anything.new.hello #=> ok
for example:
module Foo
def self.included(base)
block = Proc.new do |*symbols|
puts symbols.inspect
end
base.class.send(:define_method, :initializers, block)
end
end
class Anything
include Foo
initializers :one, :two , :three
end
I'm writing aspect-ish code more or less lifted from the chosen solution for this question that looks like the following:
class Module
def add_logging klass, *method_names
method_names.each do |method_name|
original_method = instance_method method_name
define_method method_name do |*args, &blk|
log.debug("#{klass}.#{method_name} called")
original_method.bind(klass).call(*args, &blk)
end
end
end
end
The solution in the other post doesn't require the klass parameter, but it only works for instance methods, whereas I hope to call my code like this:
module MyModule
def MyModule.module_method
p "hello"
end
class << self
add_logging self, :module_method1
end
end
Unfortunately when I run this code I get in 'bind': singleton method called for a different object (TypeError). Seeing as I pass self in the context of the class << self block, I don't understand why the bind call in the above code thinks it isn't binding to the exact same metaclass.
This should work for you:
class Module
def add_logging(*method_names)
method_names.each do |method_name|
original_method = method(method_name).unbind
define_singleton_method(method_name) do |*args, &blk|
puts "#{self}.#{method_name} called"
original_method.bind(self).call(*args, &blk)
end
end
end
end
# class method example
module MyModule
def self.module_method1
puts "hello"
end
add_logging :module_method1
end
MyModule.module_method1
# output:
#
# MyModule.module_method1 called
# hello
I currently have a superclass which has a function that I want all the subclass to call within each of its function. The function is supposed to behave like a before_filter function in rails but I am not sure on how to go about implementing before_filter. Here is an example
class Superclass
def before_each_method
puts "Before Method" #this is supposed to be invoked by each extending class' method
end
end
class Subclass < Superclass
def my_method
#when this method is called, before_each_method method is supposed to get invoked
end
end
This is one way to do it:
class Superclass
def before_each_method name
p [:before_method, name]
end
def self.method_added name
return if #__last_methods_added && #__last_methods_added.include?(name)
with = :"#{name}_with_before_each_method"
without = :"#{name}_without_before_each_method"
#__last_methods_added = [name, with, without]
define_method with do |*args, &block|
before_each_method name
send without, *args, &block
end
alias_method without, name
alias_method name, with
#__last_methods_added = nil
end
end
class SubclassA < Superclass
def my_new_method
p :my_new_method
end
def my_new_other_method
p :my_new_other_method
end
end
SubclassA.new.my_new_method
SubclassA.new.my_new_other_method
This will create a wrapper method using the alias_method_chaining method as soon as the method you'd like to wrap is defined in the subclass.
This is my solution:
require 'active_support/all'
module BeforeEach
extend ActiveSupport::Concern
module InstanceMethods
def before_each
raise NotImplementedError('Please define before_each method')
end
end
module ClassMethods
def method_added(method)
method = method.to_s.gsub(/_with(out)?_before$/, '')
with_method, without_method = "#{method}_with_before", "#{method}_without_before"
return if method == 'before_each' or method_defined?(with_method)
define_method(with_method) do |*args, &block|
before_each
send(without_method, *args, &block)
end
alias_method_chain(method, :before)
end
end
end
To use it, just include BeforeEach into your class like so:
class Superclass
include BeforeEach
def before_each
puts "Before Method" #this is supposed to be invoked by each extending class' method
end
end
class Subclass < Superclass
def my_method
#when this method is called, before_each_method method is supposed to get invoked
end
end
Subclass.new.my_method
# => Before Method
Hopefully this will work for you!
class BalanceChart < BalanceFind
include ExecutionHooks
attr_reader :options
def initialize(options = {})
#options = options
#begin_at = #options[:begin_at]
end
def months_used
range.map{|date| I18n.l date, format: :month_year}.uniq!
end
before_hook :months_data, :months_used, :debits_amount
end
module ExecutionHooks
def self.included(base)
base.send :extend, ClassMethods
end
module ClassMethods
def before
#hooks.each do |name|
m = instance_method(name)
define_method(name) do |*args, &block|
return if #begin_at.blank? ## the code you can execute before methods
m.bind(self).(*args, &block) ## your old code in the method of the class
end
end
end
def before_hook(*method_name)
#hooks = method_name
before
end
def hooks
#hooks ||= []
end
end
end