"interact" behaves oddly if used interactively

[S.J.Thompson]

Bruce,

All this discussion of 'interact' makes me feel quite nostalgic.  In
the late 80s(!) I did some work on this, since Miranda's only IO was in
the form of interact. Understanding the interleaving behaviour is
problematic, and hand-coded solutions proved to be difficult. I came up
with a way of analysing these programs, and proved some elementary
properties. The paper also contains a set of combinators for writing
interactive programs, which prefigure the monadic interaction
combinators. The paper is at:

  http://www.cs.kent.ac.uk/~sjt/Pubs/yoptrace.ps

Best regards,

Simon Thompson