This directory contains an implementation of generic IO streams in Mercury.
The streams interface uses type classes, so that users can define their
own stream types and can write generic code that will work on any
appropriate stream.

To build this library you need mvar.m and semaphore.m from the
extras/concurrency directory.  (The Mmakefile rules should copy these
here automatically.)

The following files implement the stream interfaces at various levels

    stream.m
        The pure high-level interface.  This is the interface external
        code should use to the stream library.  The file also contains
        examples of extending any stream with infinite putback and/or
        line numbering.

    lowlevel.m
        A pure low-level interface.  This interface is more useful for
        using the foreign language binding to define a new stream
        type.  This file also provides implementations of read/write one
        char which can be used in instance declarations for the
        highlevel stream typeclasses.  This allows an implementor to do
        the minimum amount of work to achieve an instance of the
        highlevel stream type class.
         
    impure.m
        An impure low-level interface, which provides the same
        functionality as lowlevel.m except the interface methods are
        impure.
