----------------------------------------------------------------------
mk_istream                                                       (Lib)
----------------------------------------------------------------------
mk_istream : ('a -> 'a) -> 'a -> ('a -> 'b) -> ('a,'b) istream

SYNOPSIS
Create a stream.

KEYWORDS
stream, imperative.

DESCRIBE
An application {mk_istream trans init proj} creates an imperative
stream of elements. The stream is generated by applying {trans} to
the state. The first element in the stream state is {init}.
The value of the state is obtained by applying {proj}.

FAILURE
If an application of {trans} or {proj} fails when applied to the state.

EXAMPLE
The following creates a stream of distinct strings.

   - mk_istream (fn x => x+1) 0 (concat "gsym" o int_to_string);
   > val it = <istream> : (int, string) istream




COMMENTS
It is aesthetically unpleasant that the underlying implementation
type is visible.

See any book on ML programming to see how functional streams are built.

SEEALSO
Lib.next, Lib.state, Lib.reset.

----------------------------------------------------------------------