[Haskell-cafe] Interesting feature

[Jules Bean]

fero wrote:
> Hi I have read in one tutorial (I can't find it again, but it was probably
> either one on ibm, gentle introduction or yaht), that it is possible to
> define relationships between free variables and the same program can be used
> to calculate either first variable when second is set or second when first
> is set. I have understood this as if I set first free variable, run program
> and write name of second variable and I get result, and vice versa. I don't
> know if I understood it well. It looks really interesting but I can't figure
> out how to do it. Is this really possible? (I doubt.) If yes show example
> please. 

See also metafont, which defines equational relationships between 
variables and solves.

Jules