4 ms·

Ruby Lazy Enumerators

141 points by vinnyglennon 7y ago

deleted 7y ago
[deleted]
mberning 7y ago
Very cool. Does anybody know when this was added? I tried looking in the ruby doc but didn't see. That is one nice thing about javadocs in comparison. They usually say “since 1.6” or whatever.
- tomstuart 7y ago
  Lazy enumerators were added in Ruby 2.0 back in 2013: https://www.ruby-lang.org/en/news/2013/02/24/ruby-2-0-0-p0-is-released/ https://www.ruby-lang.org/en/news/2013/02/24/ruby-2-0-0-p0-i...
  - mberning 7y ago
    Thanks. I have not had occasion to use them so was curious if they were a newer or just less known feature.
    - actsasbuffoon 7y ago
      I’ve used them quite a bit since they were introduced. Still, the plural of anecdote isn’t data, so I couldn’t tell you how widespread their usage is.
bonzini 7y ago
The equivalent of these is one of the things I was most happy about when I was working on GNU Smalltalk (I first added them to version 3.1 in 2008). Smalltalk already had iterators (which you created from collections with "readStream" and turned back into an array with "contents"), but no ability to filter, map or fold them. It is really, really useful.
andruby 7y ago
Good to know: the lazy block is executed in a fiber, and fibers don’t share Thread.current. It took me hours to debug why Rails I18n.locale was not honored inside the block.
- why-el 7y ago
  Can you elaborate? What were you doing to the locale? Changing it?
  - nurettin 7y ago
    Perhaps gp means that the i18n data was initialized as thread-local, so it was missing in other threads.
  - andruby 7y ago
    Rails uses I18n.locale as a "global variable" to store the locale of the request. Behind the scenes this is stored in Thread.current[]. So if you have a request that sets the locale to non-default one and you perform some work inside a lazy block, I18n.locale will return an incorrect value inside that block.
filleduchaos 7y ago
A bit of a tangent: Ruby remains the most _pleasant_ programming language I've ever used, and I've come to the conclusion that it's in no small part due to blocks (and to a lesser extent due to the ease of metaprogramming, which ironically is also my biggest headache concerning Ruby).
- nightfly 7y ago
  Having to work on Puppet custom facts and functions I don't ever really feel like I've got a good understanding of what's going on under the covers with Ruby's meta-programming. And having blocks being a distinctly different thing from lambdas (and seemingly different from every other data type in the language) just makes it more confusing. Plus having blocks being passed as something that's not really a parameter(?) is just an extra complexity that wasn't really needed. Ruby was the first non-PHP programming language I learned, and I used to love writing scripts in it, that I now write in Python instead, but the complexities outlined above kept me from ever wanting to write any complicated/large projects in it.
  - vinceguidry 7y ago
    Recommend the now out-of-print book Metaprogramming Ruby to grant insight into the hows and whys of metaprogramming. Also serves as a decent intro to Ruby for intermediate coders. Criminal that you have to buy it on the secondary market now.
  - actsasbuffoon 7y ago
    Blocks are just a convenient way to create and pass a proc. They aren’t a special data type. Lambdas and procs are similar. The only real differences are that lambdas check to see if they have the correct number of arguments, and returning inside a lambda returns from the enclosing scope.
- mberning 7y ago
  I like do describe it as ergonomics. It doesn’t really matter what I am doing, I generally enjoy doing it in Ruby. I also enjoy teaching using it. Students seem to pick up concepts very fast.
viyider491 7y ago
FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER

141 points by vinnyglennon 7y ago

deleted 7y ago

[deleted]

Very cool. Does anybody know when this was added? I tried looking in the ruby doc but didn't see. That is one nice thing about javadocs in comparison. They usually say “since 1.6” or whatever.

tomstuart 7y ago
Lazy enumerators were added in Ruby 2.0 back in 2013: https://www.ruby-lang.org/en/news/2013/02/24/ruby-2-0-0-p0-is-released/ https://www.ruby-lang.org/en/news/2013/02/24/ruby-2-0-0-p0-i...
- mberning 7y ago
  Thanks. I have not had occasion to use them so was curious if they were a newer or just less known feature.
  - actsasbuffoon 7y ago
    I’ve used them quite a bit since they were introduced. Still, the plural of anecdote isn’t data, so I couldn’t tell you how widespread their usage is.

bonzini 7y ago

The equivalent of these is one of the things I was most happy about when I was working on GNU Smalltalk (I first added them to version 3.1 in 2008). Smalltalk already had iterators (which you created from collections with "readStream" and turned back into an array with "contents"), but no ability to filter, map or fold them. It is really, really useful.

andruby 7y ago

Good to know: the lazy block is executed in a fiber, and fibers don’t share Thread.current. It took me hours to debug why Rails I18n.locale was not honored inside the block.

why-el 7y ago
Can you elaborate? What were you doing to the locale? Changing it?
- nurettin 7y ago
  Perhaps gp means that the i18n data was initialized as thread-local, so it was missing in other threads.
- andruby 7y ago
  Rails uses I18n.locale as a "global variable" to store the locale of the request. Behind the scenes this is stored in Thread.current[]. So if you have a request that sets the locale to non-default one and you perform some work inside a lazy block, I18n.locale will return an incorrect value inside that block.

filleduchaos 7y ago

A bit of a tangent: Ruby remains the most _pleasant_ programming language I've ever used, and I've come to the conclusion that it's in no small part due to blocks (and to a lesser extent due to the ease of metaprogramming, which ironically is also my biggest headache concerning Ruby).

nightfly 7y ago
Having to work on Puppet custom facts and functions I don't ever really feel like I've got a good understanding of what's going on under the covers with Ruby's meta-programming. And having blocks being a distinctly different thing from lambdas (and seemingly different from every other data type in the language) just makes it more confusing. Plus having blocks being passed as something that's not really a parameter(?) is just an extra complexity that wasn't really needed. Ruby was the first non-PHP programming language I learned, and I used to love writing scripts in it, that I now write in Python instead, but the complexities outlined above kept me from ever wanting to write any complicated/large projects in it.
- vinceguidry 7y ago
  Recommend the now out-of-print book Metaprogramming Ruby to grant insight into the hows and whys of metaprogramming. Also serves as a decent intro to Ruby for intermediate coders. Criminal that you have to buy it on the secondary market now.
- actsasbuffoon 7y ago
  Blocks are just a convenient way to create and pass a proc. They aren’t a special data type. Lambdas and procs are similar. The only real differences are that lambdas check to see if they have the correct number of arguments, and returning inside a lambda returns from the enclosing scope.
mberning 7y ago
I like do describe it as ergonomics. It doesn’t really matter what I am doing, I generally enjoy doing it in Ruby. I also enjoy teaching using it. Students seem to pick up concepts very fast.

viyider491 7y ago

FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER FREE SPINS 1coinmaster.com COIN MASTER