logoalt Hacker News

sourdecortoday at 12:41 AM3 repliesview on HN

Could someone compare this to ST in Idris?


Replies

throwaway17_17today at 3:09 AM

If you are asking in the context of Idris 2.0 (the current version), ST is not really related.

However, if you mean ST in Idris 1.0, there is a definite correlation. The mechanism that ST used for enabling local mutations was very similar to the mechanism that the typestate pattern in Rust is using. ST was a framework for formalizing State Machines in dependent types which is the mechanism TFA is analyzing.

vatsachaktoday at 2:19 AM

This is not really ST. This is analogous to eating at an old school restaurant.

You can't just walk in to the food service counter and say "give me a burger"; you need to first get a ticket from the cashier proving that you've ordered a burger and then provide that ticket to the guy at the counter.

That's literally the type state pattern

nvadertoday at 1:45 AM

Yes, I believe it should be possible for someone to do that.