Questions tagged [instance-eval]
38 questions
2
votes
3 answers
define_method inside instance_eval
When I define a method inside instance_eval block for class it creates a class method which is fine.
Eg)
class A
end
A.instance_eval do
def method; end
end
A.method #works
But when I use define_method inside instance_eval it creates instance…
Rohan Pujari
- 788
- 9
- 21
2
votes
2 answers
`instance_eval` and scopes
I have the following code:
class A
def self.scope
yield
end
def self.method_added method
self.instance_eval %{
# do something involving the added method
}
end
end
class B < A
scope do
def foo
end
…
Thermatix
- 2,757
- 21
- 51
1
vote
1 answer
Where does Ruby store method defined in instance_eval()
Here is an example:
class MyClass
end
obj = MyClass.new
obj.instance_eval do
def hello
"hello"
end
end
obj.hello
# => "hello"
obj.methods.grep "hello"
# => ["hello"]
MyClass.instance_methods.grep "hello"
# => []
MyClass's instance…
Rambo
- 1,834
- 2
- 13
- 10
1
vote
1 answer
Ruby/Rails: class_eval doesn't want to evaluate this code
To generate mocks for Omniauth, I Added this method to config/environments/development.rb
def provides_mocks_for(*providers)
providers.each do |provider|
class_eval %Q{
OmniAuth.config.add_mock(provider, {
:uid =>…
Laura
- 4,199
- 6
- 23
- 24
1
vote
1 answer
Ruby instance_exec / instance_eval with arguments
I'm trying to dynamically call a method given in a string using parameters given in the same string, I'm getting stuck on supplying the parameters though...
I currently have:
query = Query.new
while true
input = gets.split(%r{[/[[:blank:]]/,]})
…
Ozymandias
- 521
- 2
- 16
1
vote
4 answers
Passing around procs between different objects
I'm trying to make the following work but I'm obviously missing something:
class Person
def fetch
puts 'Fetch it boy!'
end
def action(data)
data.call
end
end
class Animal
def play
Person.new.action(proc { fetch })
…
stratis
- 7,750
- 13
- 53
- 94
1
vote
1 answer
Re-using Ruby DSL in a REPL or irb?
I have developed a simple DSL for tasks on a UniVerse database in jruby. It looks something like this
support = {
:host => 'localhost',
:account => 'SUPPORT'
}
uni_task support do
connect
exec "LIST FILE A1"
…
Richard Blackman
- 157
- 9
1
vote
2 answers
Ruby DSL - invoking user-provided methods within block context
A user of my Ruby DSL wishes to be able to add additional methods and invoke them within the context of an arbitrary block, for example:
def do_something
override 'flags', 'ABC'
end
project('XXX') do
configuration('debug') do
…
user1282993
1
vote
2 answers
How do I refactor code that uses `instance_exec` several times?
I'm working on a class that generates a PDF using Prawn gem. I have some similar methods. All of them start with the same line. Here is the code:
module PDFGenerator
class MatchTeamInfo
include Prawn::View
def initialize(match)
…
luuchorocha
- 99
- 8
1
vote
4 answers
Shortest code for getting all K-item combinations of N-item array, where K <= N
What is the shortest way of getting all K-item combinations of an N-item array where K <= N? I managed to write down the one below :
> [1,2,3].instance_eval "(1..size).flat_map {|i| self.combination(i).to_a }"
=> [[1], [2], [3], [1, 2], [1, 3],…
boggy
- 192
- 2
- 4
1
vote
1 answer
instance_eval's behaviour inside a instance method
Below is my snippet which i tried,
class Person
def test(arg)
self.class.instance_eval do
define_method(arg) {puts "this is a class method"}
end
end
end
irb(main):005:0> Person.new.test("foo")
=>…
Kranthi
- 1,377
- 1
- 17
- 34
1
vote
0 answers
instance_eval with custom definee context
Im trying to create DSL customization for already existing lib and i have some misunderstanding about Ruby block contexts.
Suppose we have a block saved as proc
some_block = Proc.new do
def testing; end
puts self.inspect
if self.kind_of?…
Bombazook
- 495
- 4
- 14
1
vote
2 answers
How to pass a method to instance_eval?
I want to call instance_eval on this class:
class A
attr_reader :att
end
passing this method b:
class B
def b(*args)
att
end
end
but this is happening:
a = A.new
bb = B.new
a.instance_eval(&bb.method(:b)) # NameError: undefined local…
michelpm
- 1,795
- 2
- 18
- 31
1
vote
2 answers
ruby metaprogramming - yield block not working in dynamically added method
I'm working on extending the NotAMock framework for stubbing methods in rspec, and getting the stubs to yield to a methods block.
The code in this Gist works perfectly when I code it on my own (which is done-up to resemble how NotAMock stubs…
Derick Bailey
- 72,004
- 22
- 206
- 219
1
vote
1 answer
Why does the second 'p arg' report the Foo instance?
class Foo
def with_yield
yield(self)
end
def with_instance_eval(&block)
instance_eval(&block)
end
end
f = Foo.new
f.with_yield do |arg|
p self
# => main
p arg
# => #
end
f.with_instance_eval do |arg|
p…
uzo
- 2,821
- 2
- 25
- 26