This document describes the use of sml-mode to support SML
programming, specifically on the host turing.cs.hmc.edu.
Overview
let, case, datatype, and so
forth.
SML-mode setup
To set-up sml-mode on Turing, you should just add
this single line to your .emacs file:
(load "/usr/local/sml/sml-mode/sml-mode-setup")
Your .emacs file should reside in your home directory. If you
already have a .emacs, just add the above line to the end
of that file. If you don't have a .emacs, simply create
it, making the above line the sole contents.
Note: CS-131 users should use: (load "/cs/cs131/sml-mode/sml-mode-setup-cs131") instead.
Sending code to SML
Emacs has the ability to communicate with other programs, displaying the results in a standard buffer. SML-mode uses this capability to communicate with a SML process so that you can send sections of code to the SML process. The SML process will compile the code, just as it normally would, and display the output.
To send the entire buffer to SML, you can use the
(sml-save-buffer-use-file) command, bound to "C-c
C-u" by default. As the function name implies, this will save your
buffer and then use the SML "use" command to read in the file.
If you are working on a particular function, you can have SML compile that
function by using the (sml-send-function) command, bound to
"C-c C-c" by default. Note that this command requires the
function be terminated by a trailing semicolon; otherwise, you will have to
change to the SML inferior process and enter a semicolon manually.
You can also define arbitrary regions of code to send to SML, using
(sml-send-region), on "C-c C-r". Note that
(sml-save-buffer-use-file) and
(sml-send-function) are logically just special cases of
(sml-send-region). You should be aware that they are
implemented slightly differently, though.
To define a region in Emacs, first move the cursor (also called the
point) to the beginning (or the end) of the region, and execute
the function (set-mark-command), bound to
"M-SPC" or "C-x SPC". (The "M-" means "meta";
if you don't have a meta key on your keyboard, you can use the escape
key instead.) This operation is called "setting the mark". It
fixes one end of the region, so that the region is now defined as all
the text between the "mark" and the "point". So, move the point to the
other end of the region and execute (sml-send-region), and
all the text between the point and the mark will be sent to the SML
process.
Finding errors
You may have noticed that it is often the case that you will get an
error when you compile some code in SML. SML-mode makes your
life easier by allowing you to jump straight to where the error(s)
occured. The function is called (sml-next-error) and it is
bound to "C-c '" (that's a single quote) by default.
So, to use this feature, send some code to the
inferior SML process, using any of the functions described above.
When a compile error occurs, simply execute
(sml-next-error) and Emacs will parse the SML compiler
output and move your cursor directly to the location of the compile
error. When you are done, execute (sml-next-error) again,
and sml-mode will jump to the next error.
Note: This feature doesn't appear to work with
(sml-send-function); I'd recommend using
(sml-send-region) instead.
Interacting with the SML process
If you would like to interact directly with the SML process, instead of
just sending code to it, use (sml-pop-to-shell), bound to
"C-c C-s" by default. Executing this command will place you
in an Emacs buffer which is connected directly to the SML process. You
can move around the buffer as you would any Emacs buffer, but if you
press return, the text you have typed will be sent to the SML
process.
In addition, all the normal Emacs shell commands are available. If you
don't know what those are, this is not the place to describe them all,
but you should at least know about
(comint-previous-prompt), bound to "M-p". This
will revisit the last thing you entered, allowing you to edit it if
you'd like, and enter return to send it to SML again.
If you do all your interaction with SML within this inferior shell, it will be trivial for you to obtain copies of sessions; simply cut and paste from this buffer.
If you are not already an Emacs guru, you may not be familiar with
working with multiple windows within Emacs. To switch between windows,
use (other-window), bound to "C-x o". To remove
the current window from the display (thereby reducing the number of
windows displayed by one), use (delete-window), bound to
"C-x 0" (that's a zero).
Automatic indentation
Since sml-mode knows the standard SML coding style, it should
automatically take care of indentation for you, as long as you're even
vaguely following the standard style. There are also two commands to
recalculate indentation. The first operates only on the current line:
(sml-indent-line) bound to TAB by default. The
second operates on a region: (sml-indent-region), bound to
"C-c TAB" by default. For a discussion of defining a region, see
the section on sending arbitrary regions of text to
SML.
Typing shortcuts
To make the programmer's life easier, sml-mode provides some shortcuts for commonly used constructs.
A variety of special constructs are available via the command
(sml-region), bound to "C-c RET". The constructs
available include:
To use this feature, run the (sml-region) command. Emacs will
ask you (in the minibuffer), for the "region to insert". For a complete
list of possibilities, hit TAB at this point. Enter enough
characters to uniquely identify the construct and press return.
In situations where a pipe character is appropriate (either in function
definitions or cases, sml-mode can automatically
insert it for you. For instance, say you were writing a function and
had gotten as far as:
fun length nil count = count
Now, if on a line after this, you were to execute
(sml-electric-pipe), your code would now look like:
fun length nil count = count | length
freeing you from typing the "| function_name" every time.
Similarly, if you are coding a case statement,
(sml-electric-pipe) will insert both the pipe character and
the "=>" construct for you.
(sml-electric-pipe) is bound to "M-|" by
default.
Getting help
As with all Emacs modes, sml-mode provides some limited on-line documentation. If you forget what commands or available or the keys they are bound to by default, type "M-h m" (remember that this is equivalent to "ESC h m").
There is no further documentation available besides this document and the source code to sml-mode.
Customization
Since sml-mode is written in Emacs-Lisp, it is rather customizable.
There are also a number of features I haven't mentioned. The full source is
also available, so you can hack on it to your heart's content. However, I'm
not going to engage in a full discussion of elisp programming here. My
advice would be to read the source code ("sml-mode.el") for
more details. The various variables that you can change are documented
there.
hodas@cs.hmc.edu on Sun, Feb 22, 1998 at 2:11:57 PM.
© copyright 1996 Joshua S. Hodas. All rights reserved.