OS/2 Professional/OS2PRO194.ISO/os2/prgramer/sml/sml.inf

OS/2 Help File | 1993-08-09 | 15KB | 358 lines

ΓòÉΓòÉΓòÉ 1. What is SML for PM? ΓòÉΓòÉΓòÉ

 This package contains two programs for using the functional language Standard
ML.


ΓòÉΓòÉΓòÉ 1.1. Programs, copyright and other stuff ΓòÉΓòÉΓòÉ

All programs are based on the Edinburgh Implementation of Standard ML
(v4.1.02). sml.exe is therefore (c) by Edinburgh University.

The OS/2 2.0 port of sml.exe and all other programs are written by Felix von
Normann The programs may be copied und used for free (for personal usage).
Since the programs are free, there are no warranties for any damages caused
directly or indirectly by them. All software is supplied AS IS.

This is a very early program version, so there are probably a lot of bugs. If
there is somebody interested in a 2nd version, please let me know bugs and
errors. I will try to fix them in the next release.

All comments are very welcome. The author can be reached at:
[e-mail]; Felix von Normann, Innstrasse 82, D-94036
Passau


ΓòÉΓòÉΓòÉ 1.2. programs contained in this package ΓòÉΓòÉΓòÉ

 1. readme - You should already have read this

 2. sml.exe - the OS/2 2.0 port of Edinburgh SML version 4.1.02

 3. smlpm.exe - A PM-Shell for SML. (needs sml.exe)

 4. sml.exp - An import file necessary for sml.exe (all versions)

 5. smlref.inf - A small SML reference in german (use view.exe)

 6. sml.inf - This document

 7. qref.txt - Used for online help

 8. *.ml - some samples

 9. (The DOS-port is not discussed in this manual)


ΓòÉΓòÉΓòÉ 1.3. SML - 2 versions ΓòÉΓòÉΓòÉ

 1. sml.exe - the OS/2 2.0 port of Edinburgh SML version 4.1.02

    This program is almost left in it's original version (except changing the
    float div 0.0 and garbage collection). This Program can be used either via
    stdin/stdout or by piping a file into it. It is intended to be used for
    large projects and small experiments. sml.exe is necessary for smlpm.exe

 2. smlpm.exe - A PM-Shell for SML.

    This program provides a real PM-Interface for SML including an editor. This
    program is intended to be used for small and medium programs, experiments
    and testing. Since it uses the graphics mode it is slower than than sml.exe
    but I hope it is easier to use.


ΓòÉΓòÉΓòÉ 2. Quick Start ΓòÉΓòÉΓòÉ

You can simply start the programs by:

sml.exe: sml (This starts sml.exe with a minimal heap and a default import file
"sml.exp").

smlpm: smlpm (This starts the PM-program which works interactive). You can type
in the functions on the last line only.


ΓòÉΓòÉΓòÉ 3. User's Guide ΓòÉΓòÉΓòÉ


ΓòÉΓòÉΓòÉ 3.1. sml.exe ΓòÉΓòÉΓòÉ

This section describes the usages of sml.exe


ΓòÉΓòÉΓòÉ 3.1.1. Getting started ΓòÉΓòÉΓòÉ

The syntax is: sml [-a] [-h size] [-q] [impFile]

-a means to use ANSI-sequences. SML output and user input are displayed in
different colors.

-h specifies the size of heap used for Standard ML.

-q starts ML in quiet mode

An import file can be given != sml.exp.

Example: sml -a -h 4000 smlexp.exp starts sml in ANSI-mode, with a heap of
almost 4MB. SML uses smlexp.exp as the import file.


ΓòÉΓòÉΓòÉ 3.1.2. Small expressions ΓòÉΓòÉΓòÉ

It is easy to type in small expressions. The last one can be recalled by
pressing F3.


ΓòÉΓòÉΓòÉ 3.1.3. Editing ΓòÉΓòÉΓòÉ

For larger functions the ML-commandline is not comfortable enough. There are
three possibilities to make the work easier:

 1. For OS/2 windowed shells you can use the OS/2's cut and paste features.

 2. You can use your favorite text editor. Save the file and type use file.ml.
    use (string->unit) is a standard function of ML. SML loads the file and
    evaluates the expressions.

 3. Put a small editor (must be VIO) (e.g. t.exe, supplied by IBM) into the
    PATH. Load edit.ml by typing use edit.ml This file defines 2 functions:
    edit (string->unit) invokes the texteditor, run (string->(unit*unit))
    invokes first the editor and then loads the program. If your editor is not
    t.exe you simply have to change edit.ml


ΓòÉΓòÉΓòÉ 3.2. smlpm.exe ΓòÉΓòÉΓòÉ

This section describes the features of smlpm


ΓòÉΓòÉΓòÉ 3.2.1. Getting started ΓòÉΓòÉΓòÉ

smlpm does not need any parameter. All settings are changed interactive.


ΓòÉΓòÉΓòÉ 3.2.2. If you need help ΓòÉΓòÉΓòÉ

There are 3 help textes available:

 1. Help/Infos... or view sml.inf displays this text about how to use smlpm.

 2. Help/Reference... or view smlref.inf shows a small reference af the
    languages.

 3. Help/Quick reference opens a window with a small help text (qref.txt).

In Addition there is a context help. Press F2 near or on a keyword (e.g.
abstype). Immediately a help screen will pop up.


ΓòÉΓòÉΓòÉ 3.2.3. Typing small expressions ΓòÉΓòÉΓòÉ

If you just want to type in a small expression, it is the best to type it in
directly in the main window. To avoid problems it is allowed to type in only in
the last line. Move the cursor to the bottom and type in: val x=5; As soon as
you press Enter, ML answeres your input.

You can recall the last line by typing F3.


ΓòÉΓòÉΓòÉ 3.2.4. Using the main window. ΓòÉΓòÉΓòÉ

The main window is intended to be used for small functions and experiments. See
the chapter about small functions.

To avoid problems all lines except the last one are read-only. To type text
always move to the last line

You can import a file by choosing File/Import. This simulates typing use ...

The Edit menu works exactly like e.exe. You can cut and paste text from the
window.

If you want to change the font select Options/Change font

Since smlpm actually loads sml.exe to eval your expressions you can give the
path and name of sml.exe and the import file in the options menu. You can also
change the heap size whichs defaults to 4000 KB.

It is possible to save the ML dialog by selecting File/save transcript.

You can restart sml.exe (the child process of smlpm.exe) by choosing
File/ReStart. This is important if you change options or if sml.exe stopped its
job.

All options are saved. So they are available the next time the program is
started. Be careful to leave the program via File/Quit.


ΓòÉΓòÉΓòÉ 3.2.5. Using the editor ΓòÉΓòÉΓòÉ

For larger functions you can start as many editors as you want by selecting
Tools/Editor.

Type in the whole funtion(s). That can be several lines. By pressing Alt-V (or
selecting eval) all text is copied into the main window and sent to sml.exe. By
pressing Alt-U (or selecting use) all text is saved in a temporary file and
loaded by the use-funtion

You can make full use of all edit capabilities include undo, cut, paste, ...

When all functions are working save the file by selecting file/save(as). The
default name is noname.ml. The actual name is displayed on the title bar.

Be careful with menu option clear. The text is cleared without explicitly
asking for permission.

By closing the main window ALL editor windows are closed without saving.


ΓòÉΓòÉΓòÉ 3.2.6. Keyboard shortcuts and syntax expansion ΓòÉΓòÉΓòÉ

Keyboard shortcuts:
Alt-V: Evaluate expression (edit window)
Alt-U: Evaluate expression using temporary file
Alt-B: abstype
Alt-D: datatype
Alt-A: andalso
Alt-C: case
Alt-X: exception
Alt-H: handle
Alt-I: if
Alt-L: local
Alt-N: nonfix
Alt-O: orelse
Alt-R: raise
Alt-T: then
Alt-V: val (main window)
Alt-w: while
Alt--: =>

Syntax expansion:
Ctrl-a: abstype
Ctrl-d: datatype
Ctrl-c: case of
Ctrl-i: if then else
Ctrl-l: local
Ctrl-v: let

This is specific to the german keyboard layout! These keyboard macros are
available in both, main and aditor windows.


ΓòÉΓòÉΓòÉ 4. Technical information ΓòÉΓòÉΓòÉ

This chapter describes some technical information


ΓòÉΓòÉΓòÉ 4.1. Why OS/2 2.0? ΓòÉΓòÉΓòÉ

OS/2 2.0 is a modern operation system. It allows SML to use 32 Bit and Flat
memory. Because I did not want change the SML sources more than necessary
sml.exe is started as a child process. stdin and stdout are piped into
smlpm.exe. The operating system must offer a lot of functions for IPC. I
believe this is an impossible task with Windows. SML needs a lot of processor
time. This makes it necessary to divide the work into several tasks. With
smlpm.exe there are at least 4 threads running. Because of the usage of
multithreading sml does not slow down the system dramatically.

Another reason for using OS/2 2.0 was its clear and easy to use API. In fact,
programming OS/2-PM is easier than programming windows.


ΓòÉΓòÉΓòÉ 4.2. Why not Windows? ΓòÉΓòÉΓòÉ

Porting SML to 16-Bit Windows is almost impossible. There must be made a lot of
changes in the original source files which I tried to avoid.

Of course it allmost impossible but not really impossible to port SML for
windows. It's a question af tools and I already had a windows 3.1 version (but
I did not like it because I cannot use my german keyboard). But because Win16
is sometimes annoying and all other time frustrating I do not want to spend any
more time on it.

Windows lacks the features of multithreading, interprocess communication, it
has a bad API and even worst memory management.


ΓòÉΓòÉΓòÉ 4.3. Why not NT? ΓòÉΓòÉΓòÉ

When this program was written NT was still beta. It has inherited some problems
from Windows (e.g. API). It does use a lot of resources (I do not want to give
away 10 MB of my RAM for the OS).


ΓòÉΓòÉΓòÉ 4.4. Implementation ΓòÉΓòÉΓòÉ

sml.exe was written in C (about 6000 LOC), pmsml.exe was written in C++ (about
1500 LOC short), but it is not programmed truely object-oriented. I did not use
any class-library, so it is written in low-level OS/2.

In this release smlpm starts sml.exe as a child process. It redirects the
stdout into its own window an sends all keystrokes to sml.exe. Of course this
way is unusual and can cause problems. The reason why I decided to work like
this is that I did not want to change the Edinburgh source code. That has has a
number of advantages: no additional bugs to sml.exe, easy to upgrade fam.exe,
easy to port to a different language, separate GUI-code and language code, and
some other. Since OS/2 is a true multitasking operating system, this solution
should work stable.

The main window uses an special kind of MLE (multi-line-entry field) that is
"inherited" from a normal MLE. MLE are not intended to be used interactive so
some problems my arise because of this. Why use a MLE? Because they are a
ready-to-use editor. The alternative would be to write the own epm. This would
take months. In addition, writing an editor for a complex GUI like PM (or even
Windows) is not an easy task. I bet the first release of an editor would be
very buggy. So why not reuse well-tested code? I hope this solution will not
cause many problems.

A MLE should be use with less then 16K, but I tried it with large files -
without difficulties.


ΓòÉΓòÉΓòÉ 5. trouble shooting ΓòÉΓòÉΓòÉ

This section describes some common problems


ΓòÉΓòÉΓòÉ 5.1. There is nothing happen! ΓòÉΓòÉΓòÉ

Ensure that sml.exe is in the path, or change the option-settings


ΓòÉΓòÉΓòÉ 5.2. SML is starting, but nothing happens! ΓòÉΓòÉΓòÉ

Ensure that sml.exp is in the path, or change the option-settings


ΓòÉΓòÉΓòÉ 5.3. I cannot type in anything ΓòÉΓòÉΓòÉ

The main window accepts input only if the cursor is in the last line. Scroll
down to the last line.


ΓòÉΓòÉΓòÉ 5.4. The window is blinking (flickering)! ΓòÉΓòÉΓòÉ

Thats not my fault. e.exe behaves the same way. Try to make the window as small
as possible.


ΓòÉΓòÉΓòÉ 5.5. The editor is slow. ΓòÉΓòÉΓòÉ

There is much overhead when doing graphics. Try to minimize the overhead by
making the window as small as possible.


ΓòÉΓòÉΓòÉ 5.6. SML quits work. ΓòÉΓòÉΓòÉ

Simply choose menu "File/ReStart". All definitions must be typed in from the
beginning.


ΓòÉΓòÉΓòÉ 5.7. General problems. Wrong output. ΓòÉΓòÉΓòÉ

The sml-interpreter is started as a child process. It is very difficult to
decides for smlpm.exe that sml.exe has done all work and is ready to accept
more input. I used semaphores to do this but I know there are still a lot of
problems left. If eval is not functioning the correct way try to select the use
option. I know there are a lot of bugs left and I work on them.