#11671: Allow labels starting with uppercase with OverloadedLabels -------------------------------------+------------------------------------- Reporter: inaki | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1-rc1 (Parser) | Resolution: | Keywords: ORF 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 dwincort): Just to bump this, I also have a use case for labels starting with uppercase letters. Specifically, in the same way that overloaded labels have been used for record field selectors (lenses), my group is trying to use ones that start with uppercase letters for constructor selectors (prisms). Although the ability to use them in patterns would be great, this is truly a separate issue, and we have uses for just the prisms (for example, as handlers in the foldl package [https://hackage.haskell.org/package/foldl]). Right now, we have a hack where overloaded labels starting with `_` are treated as prisms, and we write, e.g., `#_Foo` to get the prism for the constructor `Foo`. Not only is this ugly, but it means that any record fields starting with `_` are turned into prisms instead of lenses. Having labels that can start with uppercase letters would fix this. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11671#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler