EXTENS.TXT

This is file extens.txt for Moscow SML 1.02 (11 September 1994)

Extensions
==========

    * Strings can be compared with `<', `>', `<=', `>='.

    * `std_err' is a stream corresponding to `stderr' in C. All
      output to std_err is flushed immediately.

    * The `use' command enables a file containing declarations
      and expressions to be read as if its contents was entered
      from the console. Syntactically ,`use' is a top-level
      "declaration" of the form:

          use "filename";

      A file loaded by means of a `use' command may, in turn,
      contain `use' commands.


Non-standard primitives
=======================

quit : unit -> unit

    Evaluating `quit()' quits Moscow SML immediately.

system : string -> int

    `system "xxx"' causes the command xxx to be executed by the
    operating system.

    If a non-zero integer is returned, this must indicate that
    the operating system has failed to execute the command.
    But, under MS DOS, the integer returned always equals to
    zero...

    The primitive `system' will work only if the corresponding
    primitive has been added to the Caml Light run-time system.

print : 'a -> 'a

    `print' is a polymorphic function provided as a quick
    debugging aid. This is an identity function, which as a
    side-effect prints its argument exactly as it would be
    printed at top-level.

    The effect of `print' is different from that in
    SML/NJ `print' when the argument is a string (but similar
    to that of Edinburgh ML).  A function similar to SML/NJ `print'
    for printing strings can be defined as follows:

          fun show t = output(std_out, t)

printDepth : int ref

    This variable determines the depth (in terms of nested 
    constructors, records, tuples, and lists) to which values 
    are printed by the top-level value printer and the function 
    `print'. The components of the value whose depth is greater 
    than `printDepth' are printed as `#'.

    The initial value of `printDepth' is 20. This value can be 
    changed by the user's program at any moment.

printLength : int ref

    This variable determines the way in which list values are 
    printed by the top-level value printer and the function 
    `print'. If the length of a list is greater than 
    `printLength', only the first `printLength' elements are 
    printed, whereas the remaining elements are printed as 
    `...'.

    The initial value of `printLength' is 200. This value 
    can be changed by the user's program at any moment.

makestring : 'a -> string

    `makestring' is an overloaded function whose argument must
    be resolved as either `int', `real', or `string'. It
    returns a string what `print' would produce on the screen.

flush_out : outstream -> unit

    `flush_out' ensures that the consumer associated with an
    outstream has received all of the characters that have been
    written to that stream.

can_input : instream * int -> bool

    `can_input' takes an instream and a number and determines
    whether or not that many characters may be read from that
    stream without blocking.  NOTE: In future releases, the type
    of can_input may change to instream -> int (as in SML/NJ).

input_line : instream -> string

    `input_line' returns a string consisting of the characters
    from an instream up through, and including, the next
    end-of-line character. If the end-of-stream is reached
    without reaching an end-of-line character, all remaining
    characters from the stream (without an end-of-line
    character!) are returned.

open_append : string -> outstream

    Files may be open for output while preserving
    their contents by using `open_append'. Subsequent output to
    the outstream returned by `open_append' is appended to the
    contents of the specified file.

Loading files from the command line
===================================

Entering

  mosml.exe filename1 ... filenameN

is equivalent to entering

  mosml.exe

and, when Moscow SML have started, entering

  use "filename1"; ... use "filenameN";