[Haskell-cafe] Identity of indiscernibles (Was: Alternative name for return)

Jerzy Karczmarczuk jerzy.karczmarczuk at unicaen.fr
Thu Aug 8 11:38:08 CEST 2013

Tom Ellis:
> If I were writing a Haskell compiler I could certainly define 'IO' to be a
> datatype that would allow me to compare 'putStr "c"' to itself.  The
> comparison could not be of operational equivalence, but it would still be
> possible to compare values in IO in a reasonable sense.

Would you add to all this:
getLine == getLine

Good luck!

I suspect that you would have to establish also the equality relation 
between functions and between infinite streams.
And you would end as Giordano Bruno and Jeanne d'Arc. But for different 

Jerzy Karczmarczuk

More information about the Haskell-Cafe mailing list