My _very_ naive question is whether Template Haskell should have all the features of the latest language? Perhaps it could instead be limited to a simpler subset so that it could become a bolt-on to the rest of the compiler and it could be compiled and implemented independently using an older compiler and libraries.
Howard > On Oct 17, 2023, at 9:54 AM, Viktor Dukhovni <ietf-d...@dukhovni.org> wrote: > > On Tue, Oct 17, 2023 at 04:54:41PM +0100, Adam Gundry wrote: > >> Thanks for starting this discussion, it would be good to see progress in >> this direction. As it happens I was discussing this question with Ben and >> Matt over dinner last night, and unfortunately they explained to me that it >> is more difficult than I naively hoped, even once wired-in and known-key >> things are moved to ghc-internal. >> >> The difficulty is that, as a normal Haskell library, ghc itself will be >> compiled against a particular version of base. Then when Template Haskell is >> used (with the internal interpreter), code will be dynamically loaded into a >> process that already has symbols for ghc's version of base, which means it >> is not safe for the code to depend on a different version of base. This is >> rather like the situation with TH and cross-compilers. > > To avoid that problem, GHC's own dependency on "base" could be indirect > via a shared object with versioned symbol names and a version-specific > SONAME (possibly even a private to GHC SONAME and private symbol version > names). Say "libbase.so.4.19.1". > > The dependency on "base" in the TemplatHaskell generated code would then > also need to be dynamic, allowing the two versions of base to coexist > without conflict, both in turn depdent on a common version of the GHC > internal libraries. > > This would of course somewhat complicate binary distributions, but that > should be manageable. Perhaps there are less invasive (more clever) > solutions? > > -- > Viktor > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs