One of the things that a lot of people are exited about in Emacs 26 is the introduction of basic threading. Another, less mentioned, feature is generators. The excellent Chris Wellons has a must-read post that talks about both of these innovations. <\/p>\n
He first considers generators, which he describes as mostly modeled after Python generators and, to a lesser extent, JavaScript generators. Generators return an iterator object that performs a calculation but can stop in middle of the operation to return a value. When it’s called again, it produces the next value and stops again. Python users will be familiar with the idea. <\/p>\n
In Elisp, the generators are implemented as closures. Wellons describes how they work and some of the gotchas involved but if you’ve ever implemented a counter function that return the next sequential integer each time it’s called, you’ll be familiar with the concept. <\/p>\n
Next Wellons talks about the threading implementation. He says that they’re basically pthreads and that they should be considered a first step in bringing threads to Emacs. Again, he discusses some of the things that can go wrong. <\/p>\n
Finally, being Wellons, he wrote an implementation of generators using threads. It was just a proof-of-concept implementation meant to give him some experience in using the new facilities. You can take a look at the code<\/a> on GitHub if you’re interested. <\/p>\n As always with Wellons’ posts, I learned some new things by reading it. If you do any Elisp at all, you should take a look. <\/p>\n","protected":false},"excerpt":{"rendered":" One of the things that a lot of people are exited about in Emacs 26 is the introduction of basic threading. Another, less mentioned, feature is generators. The excellent Chris Wellons has a must-read post that talks about both of … Continue reading