#14107: Implement Semigroup and Monoid instances for the ST monad -------------------------------------+------------------------------------- Reporter: plato | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Core Libraries | Version: 8.2.1 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by plato): I dug into the source code and have two questions: 1. Adding the `Monoid` and `Semigroup` instances was simple enough, but I noticed some instances have a `since` annotation. Should I add one, too? If so, which version should I add? 2. I tested this by recompiling ghc, running `ghc-stage2` interactively and typing `:info ST`, which printed the correct instances. I also ran `./validate`. Are there any other tests I shall perform for this kind of feature? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14107#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler