Re: [Haskell-cafe] [] == []

10 Mar 2015


      On Tue, Mar 10, 2015 at 6:54 PM, Brandon Allbery 
wrote:
...
On Tue, Mar 10, 2015 at 9:18 AM, Rustom Mody 
wrote:
...
On Tue, Mar 10, 2015 at 2:03 PM, Brandon Allbery 
wrote:
...
On Mon, Mar 9, 2015 at 10:33 PM, Rustom Mody 
wrote:
...
1. Which instance of == is being used?
2. Is there some option controlling this behavior?
The instance being used is (), and it's controlled by
-XExtendedDefaultRules.
https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/interactive-...
Thats what I first thought
Tried starting ghci with  -XNoExtendedDefaultRules
but it does not turn it off
Looks like -X only affects compiler flags:
Prelude> :showi language
    base language is: Haskell2010
    with the following modifiers:
      -XNoMonomorphismRestriction
      -XNoDatatypeContexts
      -XNondecreasingIndentation
      -XExtendedDefaultRules
Probably need to use :seti inside of ghci, or in a .ghci / ghci.ini file.
Ok that did it -- Thanks Brandon.

Also thanks Taylor for the exact pointer to the divergence between ghc and
ghci semantics