"interact" behaves oddly if used interactively

[Christian Maeder]

I wrote:
>>"main=interact id" basically echoes every line of my input, whereas
>>"main=interact show" correctly waits for EOF before 
>>outputting something.

The unix "cat" and "sort" behave in a similar way ("sort" obviuously has 
to wait for the last line.)

Still I would regard it to be more "pure" (or "abstract") if my input 
would always be mapped to visibly separate output.

Christian