#10871: Implement "fat" interface files which can be directly compiled without source -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Resolution: | Keywords: backpack 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 simonmar): I completely agree that we shouldn't save source files and try to replay compilation from there - indeed I'm suggesting that we shouldn't record/replay anything at all, and just start from the cabal source packages each time we need to compile or typecheck. Maybe a simple example will help focus this discussion. Imagine we have packages A and B, where A has a B-shaped hole. We can do {{{ cabal install A }}} which just typechecks A, and we can do {{{ cabal install A B }}} which compiles A and B. Now, "cabal install A B" must work and produce the same results regardless of whether we previously did "cabal install A", because cabal is just a function from source packages to compiled packages. So the only thing we can do in response to "cabal install A" is to cache something that might be useful later, which is what the fat interface files are: they let us avoid some of the work that we will need to do in a future "cabal install A B" for any B. Since we have to support "cabal install A B" without a previous "cabal install A", there's no new functionality in saving fat interfaces. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10871#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler