I've been struggling with something for a while and was hoping someone who
knows more about me than this would be able to help. I have this gist: https://gist.github.com/kddeisz/d975ef9a5e45a88bacb03e9f2c1fcf67. I'm
attempting to build in generic callbacks that I can port into a number of
our gems here (this is not an invitation for a discussion on the merits of
callbacks).
irb(main)> a.call { puts "hello" }
yielding
LocalJumpError: no block given (yield)
from (irb):13:in `block in irb_binding'
from (irb):15
from /usr/local/google/home/mdemello/.rbenv/versions/2.3.1/bin/irb:11:in
`<main>'
i.e. the block passed to Proc#call does not get passed to the lambda itself.
martin
···
On Wed, Sep 21, 2016 at 11:42 AM, Kevin Deisz <kevin.deisz@gmail.com> wrote:
Hi everyone,
I've been struggling with something for a while and was hoping someone who
knows more about me than this would be able to help. I have this gist: https://gist.github.com/kddeisz/d975ef9a5e45a88bacb03e9f2c1fcf67\. I'm
attempting to build in generic callbacks that I can port into a number of
our gems here (this is not an invitation for a discussion on the merits of
callbacks).
No matter how much I mess with it I can't get it working. The thing is, I
know this is a solvable problem because Rails does this in this file: https://github.com/rails/rails/blame/master/activesupport/lib/active_
support/callbacks.rb, so there has to be a way. Unfortunately, I can't
seem to replicate their approach.
I've got them working nicely for before and after callbacks. My issue
comes with around callbacks.
> # still working
> chain.around { |target, &block| puts 'abefore'; block.call; puts 'aafter' }
> # boom - in `block in <main>': no block given (yield) (LocalJumpError)
> chain.around { puts 'aabefore'; yield; puts 'aaafter' }
Both codes pass the block "{...}" to the method, "chain.around".
In the working case, the block accept parameter "block" as
a Proc object, then call it in it as "block.call".
In the later case, the block tries to call a block given to the block, Since it's not given, ruby showed the message, 'no block given'.
We can use yield in a method to call a bock given to the method.
I think I did something like this a long time ago. You'll probably
find it still in the archives. Actually it is so long ago, I don't
remember the details but I do remember that there was before, after
and around code.
Kind regards
robert
···
On Wed, Sep 21, 2016 at 8:42 PM, Kevin Deisz <kevin.deisz@gmail.com> wrote:
I've been struggling with something for a while and was hoping someone who
knows more about me than this would be able to help. I have this gist: https://gist.github.com/kddeisz/d975ef9a5e45a88bacb03e9f2c1fcf67\. I'm
attempting to build in generic callbacks that I can port into a number of
our gems here (this is not an invitation for a discussion on the merits of
callbacks).
irb(main)> a.call { puts "hello" }
yielding
LocalJumpError: no block given (yield)
from (irb):13:in `block in irb_binding'
from (irb):15
from /usr/local/google/home/mdemello/.rbenv/versions/2.3.1/bin/irb:11:in `<main>'
i.e. the block passed to Proc#call does not get passed to the lambda itself.
