#11049: Allow CallStacks to be hidden or cut -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #11035 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This is a spin off of #11035. I’d like to see a way for a function `foo` * use another function `bar` with a `(?_::CallStack)` constraint so that `bar` will _not_ print a call stack, and * use another function `bar` with a `(?_::CallStack)` constraint so that if `bar` prints a call stack, it will stop at the call to `foo`. This might be possible to implement with a special `rootCallStack :: CallStack` which is a value such that {{{ x `pushCallStack` rootCallStack = rootCallStack }}} but {{{ rootCallStack `pushCallStack` x = rootCallStack “:” x }}} as before and a call stack that consists of only a rootCallStack causes no stack trace to be printed. The use case is to provide the user of a library less cluttered call stacks that do not expose unhelpful details and allow her to quickly spot the relevant information. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11049 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler