#8113: Cannot override ghci builtin commands with :def[!] -------------------------------------+------------------------------------- Reporter: duncan | Owner: Type: bug | Status: closed Priority: normal | Milestone: 7.8.1 Component: GHCi | Version: 7.6.3 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: Other | Difficulty: Easy (less than 1 Test Case: | hour) ghci/scripts/T8113 | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------- Comment (by rwbarton): I suppose what I specifically want to happen when I enter a `:command` is an algorithm like this. If the name I entered is an exact match for a macro or built-in, use that name. Otherwise, try to complete the name to the name of a ''built-in'' in the traditional way. If this succeeds, use the resulting name. Otherwise, try to complete the name to the name of a macro, and use the resulting name if that succeeds, otherwise give up. In all cases where we got a name, use the ''macro'' of that name if there is one, and otherwise use the built-in. (Obviously, for `::command`, ignore macros entirely.) In other words, built-ins should take precedence over macros for the purpose of name ''completion'', but macros should take precedence over built-ins for the purpose of name ''lookup''. This is backwards- compatible from the perspective of the user who is not aware of the change—`:t` will always mean `:type`, as long as the user has no macro named `:t`, just like in previous versions of ghci—while still allowing the aware user to redefine exactly what `:type` means. And it's flexible enough in that if the user really wants `:t` to complete to some other macro `:test` that they've written, they can always define another macro `:t` to expand to `:test`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8113#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler