sml-mode.texi

\input texinfo @c -*-texinfo-*-

@comment "@(#)$Name$:$Id$"

@comment Documentation for the GNU Emacs SML mode.
@comment Copyright (C) 1997-1999 Matthew J.@: Morley

@comment This file is part of the sml-mode distribution.

@comment sml-mode is free software; you can redistribute it and/or modify
@comment it under the terms of the GNU General Public License as published by
@comment the Free Software Foundation; either version 3 of the License,
@comment or (at your option) any later version.

@comment sml-mode is distributed in the hope that it will be useful,
@comment but WITHOUT ANY WARRANTY; without even the implied warranty of
@comment MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
@comment GNU General Public License for more details.

@comment You should have received a copy of the GNU General Public License
@comment along with sml-mode; see the file COPYING.  If not, write to
@comment the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

@setfilename sml-mode.info
@settitle SML mode - The Emacs SML editing mode
@dircategory Emacs
@direntry
* sml:(sml-mode).	Emacs mode for editing SML
@end direntry
@setchapternewpage on

@titlepage
@sp 5
@center @titlefont{Editing and Running Standard ML}
@center @titlefont{under GNU Emacs}
@sp 5
@center {SML mode, Version $Name$}
@center {August 1999}
@sp 2
@author Authors: Matthew J.@: Morley and Stefan Monnier

@page
@vskip 0pt plus 1filll
Copyright @copyright{} (Anon) 

@sp 1
@noindent
GNU General Public License as published by the Free Software Foundation;
either version 3, or (at your option) any later version.

@sp 1
@noindent
SML mode is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.

@sp 1
@noindent
You should have received a copy of the GNU General Public License along
with GNU Emacs; see the file COPYING. If not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

@end titlepage

@setchapternewpage off
@headings double

@c ============================================================ TOP NODE

@node Top, Copying, (dir), (dir)

@ifinfo
@chapter SML Mode Info

@c == Top, Copying, (dir), (dir) =======================================

@noindent
You are looking at the top node of the Info tree documenting
@sc{sml-mode} (Version $Name$). Not all functions are documented here, but
those that aren't you probably won't miss. All commands and settable
variables have built-in documentation, as per usual Emacs conventions.
@end ifinfo

@menu
* Copying::             You can copy SML mode
* Introduction::        Setting things up
* SML Mode::            Editing SML source
* Interaction Mode::    Running ML processes
* Configuration::       Menus, highlighting, setting defaults

Indexes
* Command Index::       Commands you can invoke
* Variable Index::      Variables you can set
* Key Index::           Default keybindings

Introduction
* Contributors::        Who did what
* Getting Started::     What to tell Emacs
* Getting Help::        How Emacs can help

SML Mode
* Basics::              On entering SML mode
* Indentation::         Prettying SML text
* Magic Insertion::     Templates and electric keys
* SML Mode Defaults::   Variables controlling indentation

Interaction Mode
* Running ML::          Commands to run the ML compiler in a buffer
* ML Interaction::      Sending program fragments to the compiler
* Tracking Errors::     Finding reported syntax errors
* Process Defaults::    Setting defaults for process interaction

Configuration
* Hooks::               Creating hooks
* Key Bindings::        Binding commands to keys
* Highlighting::        Syntax colouring
* Advanced Topics::     You may need to speak Emacs Lisp
@end menu


@c ============================================================= COPYING

@node Copying, Introduction, Top, Top

@ifinfo
@chapter Copying

@c == Copying, Introduction, Top, Top ==================================

@noindent
You can freely copy, modify and redistribute SML mode because it's
made available under the liberal terms of the GNU General Public
License.

GNU General Public License as published by the Free Software Foundation;
either version 3, or (at your option) any later version.

SML mode is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.

You should have received a copy of the GNU General Public License along
with GNU Emacs; see the file COPYING. If not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

@end ifinfo




@c ======================================================== INTRODUCTION

@node Introduction, SML Mode, Copying, Top

@chapter Introduction

@c == Introduction, SML Mode, Copying, Top =============================


@noindent
SML mode is a major mode for Emacs for editing Standard ML. It has
some novel bugs, and some nice features:

@itemize @bullet
@item
Automatic indentation of sml code---a number of variables to customise
the indentation.
@item
Easy insertion for commonly used templates like let, local, signature,
and structure declarations, with minibuffer prompting for types and
expressions.
@item
Magic pipe insertion: @code{|} automatically determines if it is used
in a case or fun construct, and indents the next line as appropriate, 
inserting @code{=>} or the name of the function.
@item
Inferior shell for running ML. There's no need to leave Emacs, just keep
on editing while the compiler runs in another window.
@item
Automatic ``use file'' in the inferior shell---you can send files,
buffers, or regions of code to the ML subprocess.
@item
Menus, and syntax and keyword highlighting supported for Emacs 19 and
derivatives.
@item
Parsing errors from the inferior shell, and repositioning the
source with next-error---just like in c-mode.
@item
SML mode can be easily configured to work with a number of Standard
ML compilers, and other SML based tools.
@end itemize

@menu
* Contributors::        Who did what
* Getting Started::     What to tell Emacs
* Getting Help::        How Emacs can help
@end menu



@c ======================================================== CONTRIBUTORS

@node Contributors, Getting Started, Introduction, Introduction

@section Contributors to the SML mode
@cindex Contributors
@cindex Authors

Contributions to the package are welcome.  I have limited time to work
on this project, but I will gladly add any code that you contribute to
me to this package.

Although the history of sml-mode is obscure, it seems that
the following persons have made contributions to sml-mode:

@itemize @bullet
@item
Lars Bo Nielsen wrote the original version of the code, providing the
sml editing mode and the inferior-sml support.

@item
Olin Shivers (@samp{shivers@@ai.mit.edu}) hacked the inferior-sml support
to use comint and call the whole thing ml-mode.

@item
Steven Gilmore supposedly provided some early attempt at menubar support.

@item
Matthew J. Morley (@samp{matthew@@verisity.com}) was maintainer for
a long time (until version 3.4) and provided many additions and fixes in
all areas.

@item
Frederick Knabe (@samp{knabe@@ecrc.de}) provided the original code for
font-lock and hilite support as well as for proper handling of nested
comments and of all the string escape sequences.

@item
Matthias Blume (@samp{blume@@kurims.kyoto-u.ac.jp}) provided a sml-make
which was replaced by sml-compile.

@item
Monnier Stefan (@samp{monnier@@iro.umontreal.ca}) completely reworked the
indentation engine as well as most of the rest of the code and is
the current maintainer since after version 3.4.

@end itemize


@c ===================================================== GETTING STARTED

@node Getting Started, Getting Help, Contributors, Introduction

@section Getting started

@c == Getting Started, Getting Help, Contributors, Introduction ========


@noindent
With luck your system administrator will have installed SML mode
somewhere convenient, so it will just magically all work---you can
skip the rest of this getting started section. Otherwise you will need
to tell Emacs where to find all the SML mode @file{.el} files, and
when to use them. The where is addressed by locating the Lisp code on
your Emacs Lisp load path---you may have to create a directory for this,
say @file{/home/mjm/elisp}, and then insert the following lines in your
@file{/home/mjm/.emacs} file:

@lisp
(add-to-list 'load-path "/home/mjm/elisp")
(autoload 'sml-mode "sml-mode" "Major mode for editing SML." t)
(autoload 'run-sml "sml-proc" "Run an inferior SML process." t)
@end lisp

@noindent
The first line adjusts Emacs' internal search path so it can locate the
Lisp source you have copied to that directory; the second and third
lines tell Emacs to load the code automatically when it is needed. You
can then switch any Emacs buffer into SML mode by entering the command

@example
M-x sml-mode
@end example

@noindent
It is usually more convenient to have Emacs automatically place the
buffer in SML mode whenever you visit a file containing ML
programs. The simplest way of achieving this is to put something like

@lisp
(add-to-list 'auto-mode-alist '("\\.\\(sml\\|sig\\)\\'" . sml-mode))
@end lisp

@noindent
also in your @file{.emacs} file. Subsequently (after a restart), any
files with these extensions will be placed in SML mode buffers when
you visit them.


You may want to pre-compile the @file{sml-*.el} files (@kbd{M-x
byte-compile-file}) for greater speed---byte compiled code loads and
runs somewhat faster.


@c ======================================================== GETTING HELP

@node Getting Help, , Getting Started, Introduction

@section Help!

@c == Getting Help, , Getting Started, Introduction ====================


@noindent
You're reading it. Apart from the on-line info tree (@kbd{C-h i} is the
Emacs key to enter the @code{info} system---you should follow the brief
tutorial if this is unfamiliar), there are further details on specific
commands in their documentation strings. Only the most useful
SML mode commands are documented in the info tree: to find out more
use Emacs' help facilities.

Briefly, to get help on a specific function use @kbd{C-h f} and enter
the command name. All (almost all, then) SML mode commands begin
with @code{sml-}, so if you type this and press @key{TAB} (for
completion) you will get a list of all commands. Another way is to use
@kbd{C-h a} and enter the string @code{sml}. This is command apropos; it
will list all commands with that sub-string in their names, and any key
binding they may have in the current buffer. Command apropos gives a
one-line synopsis of what each command does.

Some commands are also variables---such things are allowed in Lisp, if
not in ML! @xref{Command Index}, for a list of (info) documented
functions. @xref{Variable Index}, for a list of user settable variables
to control the behaviour of SML mode.

Before accessing this information on-line from within Emacs you may have
to set the variable @code{sml-mode-info}. Put in your @file{.emacs} file
something like:

@vindex sml-mode-info
@findex sml-mode-info
@kindex @kbd{C-c C-i}
@lisp
(setq sml-mode-info "/home/mjm/info/sml-mode.info")
@end lisp

@noindent
When different from the default this variable should be a string giving
the absolute name of the @file{.info} file. Then @kbd{C-c C-i} in
SML mode (i.e., the command @kbd{M-x sml-mode-info}) will bring up
the manual. This help is also accessible from the menu. (Resetting this
variable will not be necessary if your site administrator has been kind
enough to install SML mode and its attendant documentation in the
Emacs hierarchy.)


@c ============================================================ SML MODE

@node SML Mode, Interaction Mode, Introduction, Top

@chapter Editing with SML Mode

@c == SML Mode, Interaction Mode, Introduction, Top ====================


@noindent
Now SML mode provides just a few additional editing commands. Most of
the work has gone into implementing the indentation algorithm which, if
you think about it, has to be complicated for a language like
ML. @xref{SML Mode Defaults,,Indentation Defaults}, for details on how
to control some of the behaviour of the indentation algorithm. Principal
goodies are the `electric pipe' feature, and the ability to insert
common SML forms (macros or templates).

@menu
* Basics::              On entering SML mode
* Indentation::         Prettying SML text
* Magic Insertion::     Templates and electric keys
* SML Mode Defaults::   Variables controlling indentation
@end menu


@c ============================================================== BASICS

@node Basics, Indentation, SML Mode, SML Mode

@section On entering SML mode

@c == Basics, Indentation, SML Mode, SML Mode ==========================

@noindent


@deffn Command sml-mode
This switches a buffer into SML mode. This is a @emph{major mode} in
Emacs. To get out of SML mode the buffer's major mode must be set to
something else, like @t{text-mode}. @xref{Getting Started}, for details
on how to set this up automatically when visiting an SML file.
@end deffn

Emacs is all hooks of course. A hook is a variable: if the variable is
non-nil it binds a list of Emacs Lisp functions to be run in some order
(usually left to right). You can customise SML mode with these
hooks:


@defvr Hook sml-mode-hook
Default: @code{nil}

This is run every time a new SML mode buffer is created (or if you
type @kbd{M-x sml-mode}). This is one place to put your preferred key
bindings. @xref{Configuration}, for some examples.
@end defvr


@c ========================================================= INDENTATION

@node Indentation, Magic Insertion, Basics, SML Mode

@section Automatic indentation

@c == Indentation, Magic Insertion, Basics, SML Mode ===================


@noindent
ML is a complicated language to parse, let alone compile. The
indentation algorithm is a little wooden (for some tastes), and the best
advice is not to fight it! There are several variables that can be
adjusted to control the indentation algorithm (@pxref{SML Mode
Defaults,,Customising SML Mode}, below).


@deffn Command indent-for-tab-command
Key: @key{TAB}
@kindex @key{TAB}

This command indents the current line. If you set the indentation of the
previous line by hand, @code{indent-for-tab-command} will indent relative to
this setting.
@end deffn


@deffn Command indent-region
Key: @kbd{C-M-\}
@kindex @kbd{C-M-\}

Indent the current region. Be patient if the region is large (like the
whole buffer).
@end deffn


@deffn Command sml-back-to-outer-indent
Key: @kbd{M-@key{TAB}}
@kindex @kbd{M-@key{TAB}}

Unindents the line to the next outer level of indentation.
@end deffn



Further indentation commands that Emacs provides (generically, for all
modes) that you may like to recall:

@itemize @minus
@item
@kbd{M-x newline-and-indent}

On @key{LFD} by default.
@kindex @key{LFD}
Insert a newline, then indent according to the major mode. @xref{Program
Indent,,Indentation for Programs,emacs,The Emacs Editor Manual}, for
details.

@item
@kbd{M-x indent-rigidly}

On @kbd{C-x @key{TAB}} by default.
@kindex @kbd{C-x @key{TAB}}
Moves all lines in the region right by its argument (left, for negative
arguments). @xref{Indentation,,,emacs,The Emacs Editor Manual}.

@item
@kbd{M-x indent-for-comment} 

On @kbd{M-;} by default.
@kindex @kbd{M-;}
Indent this line's comment to comment column, or insert an empty
comment. @xref{Comment Commands,,,emacs,The Emacs Editor
Manual}.

@item
@kbd{M-x indent-new-comment-line}

On @kbd{M-@key{LFD}} by default.
@kindex @kbd{M-@key{LFD}}
Break line at point and indent, continuing comment if within one.
@xref{Multi-Line Comments,,,emacs,The Emacs Editor Manual}.
@end itemize

@kindex @kbd{C-x ;}
As with other language modes, @kbd{M-;} gives you a comment at the end
of the current line. The column where the comment starts is determined
by the variable @code{comment-column}---default is 40, but it can be
changed with @code{set-comment-column} (on @kbd{C-x ;} by default).


@c ===================================================== MAGIC INSERTION

@node Magic Insertion, SML Mode Defaults, Indentation, SML Mode

@section Electric features

@c == Magic Insertion, SML Mode Defaults, Indentation, SML Mode ========


@noindent
Electric keys are generally pretty irritating, so those provided by
SML mode are fairly muted. The only truly electric key is @kbd{;},
and this has to be enabled to take effect.


@deffn Command sml-electric-pipe
Key: @kbd{M-|}
@kindex @kbd{M-|}

When the point is in a `case' statement this opens a new line, indents
and inserts @code{| =>} leaving point just before the double arrow; if
the enclosing construct is a `fun' declaration, the newline is indented
and the function name copied at the appropriate column. Generally, try
it whenever a @code{|} is wanted---you'll like it!
@end deffn

@deffn Command sml-electric-space
Key: @kbd{M-SPC}
@kindex @kbd{M-SPC}

When the point is after a keyword like `let', this inserts the
corresponding predefined skeleton if one exists.  Else it just inserts a
space.  Another way to insert those skeletons is to use
@code{sml-insert-form}, described below.
@end deffn

@deffn Command sml-electric-semi
Key: @kbd{;}
@kindex @kbd{;}

Just inserts a semi-colon, usually. The behaviour of this command is
governed by the variable @code{sml-electric-semi-mode}.
@end deffn


@defvr Variable sml-electric-semi-mode
Default: @code{nil}

If this variable is @code{nil}, @code{sml-electric-semi} just inserts a
semi-colon, otherwise it inserts a semi-colon and a newline, and indents
the newline for SML.
@end defvr


@deffn Command sml-insert-form
Key: @kbd{C-c @key{RET}}
@kindex @kbd{C-c @key{RET}}

Interactive short-cut to insert common ML forms (a.k.a.@: macros, or
templates). Recognised forms are `let', `local', `case', `abstype',
`datatype', `signature', `structure', and `functor'. Except for `let'
and `local', these will prompt for appropriate parameters like functor
name and signature, etc.. This command prompts in the mini-buffer, with
completion.

By default @kbd{C-c @key{RET}} will insert at point, with the
indentation of the current column; if you give a prefix argument (i.e.,
@kbd{C-u C-c @key{RET}}) the command will insert a newline first,
indent, and then insert the template.
@end deffn

@code{sml-insert-form} is also extensible: see @ref{Configuration} for
further details.



@c ======================================================= MODE DEFAULTS

@node SML Mode Defaults, , Magic Insertion, SML Mode

@section Indentation defaults

@c == SML Mode Defaults, , Magic Insertion, SML Mode ===================


@noindent
Several variables try to control the indentation algorithm and other
features of SML mode.  Most of them are still in flux so they are not
described here yet.
If the default values are not acceptable you can set these variables
permanently in your @file{.emacs} file. @xref{Configuration}, for
details and examples.


@defvr Variable sml-indent-level
@findex sml-indent-level
Default: @code{4}

This variable controls the block indentation level.
@end defvr

@c end vtable


@c ========================================================= INTERACTION

@node Interaction Mode, Configuration, SML Mode, Top

@chapter Running ML under Emacs

@c == Interaction Mode, Configuration, SML Mode, Top ===================


@noindent
The most useful feature of SML mode is that it provides a convenient
interface to the compiler. How serious users of ML put up with a
teletype interface to the compiler is beyond me@.@.@. but perhaps there
are other interfaces to compilers that require one to part with serious
money. Such remarks can quickly become dated---in this case, let's hope
so!

Anyway, SML mode provides an interaction mode,
@code{inferior-sml-mode}, where the compiler runs in a separate buffer
in a window or frame of its own. You can use this buffer just like a
terminal, but it's usually more convenient to mark some text in the
SML mode buffer and have Emacs communicate with the sub-process. The
features discussed below are syntax-independent, so they should work
with a wide range of ML-like tools and compilers. @xref{Process
Defaults}, for some hints.

@findex inferior-sml-mode
@code{inferior-sml-mode} is a specialisation of the @file{comint}
package that comes with Emacs and XEmacs.


@menu
* Running ML::          Commands to run the ML compiler in a buffer
* ML Interaction::      Sending program fragments to the compiler
* Tracking Errors::     Finding reported syntax errors
* Process Defaults::    Setting defaults for process interaction
@end menu



@c ========================================================== RUNNING ML

@node Running ML, ML Interaction, Interaction Mode, Interaction Mode

@section Starting the compiler

@c == Running ML, ML Interaction, Interaction Mode, Interaction Mode ==

@noindent
Start your favourite ML compiler with the command

@example
@kbd{M-x run-sml}
@end example

@noindent
This creates a process interaction buffer that inherits some key
bindings from SML mode and from @file{comint} (@pxref{Shell Mode, ,
, emacs, The Emacs Editor Manual}). Starting the ML compiler adds some
functions to SML mode buffers so that program text can be
communicated between editor and compiler (@pxref{ML Interaction}).

The name of the ML compiler is the first thing you should know how to
specify:


@defvar sml-program-name
Default: @code{"sml"}

The program to run as ML. You might need to specify the full path name
of the program.
@end defvar


@defvar sml-default-arg
Default: @code{""}

Useful for Poly/ML users who may supply a database file, or others who
have wrappers for setting various options around the command to run the
compiler. Moscow ML people might set this to @code{"-P full"}, etc..
@end defvar

The variable @code{sml-program-name} is a string holding the name
of the program @emph{as you would type it at the shell}. You 
can always choose a program different to the default by invoking

@example
@kbd{C-u M-x run-sml}
@end example

@noindent
With the prefix argument Emacs will prompt for the command name and any
command line arguments to pass to the compiler. Thereafter Emacs will
use this new name as the default, but for a permanent change you should
set this in your @file{.emacs} with, e.g.:

@lisp
(setq sml-program-name "nj-sml")
@end lisp


@deffn Command run-sml
Launches ML as an inferior process in another buffer; if an ML process
already exists, just switch to the process buffer. A prefix argument
allows you to edit the command line to specify the program, and any
command line options.
@end deffn


@defvr Hook inferior-sml-mode-hook
Default: @code{nil}

@kbd{M-x run-sml} runs @code{comint-mode-hook} and
@code{inferior-sml-mode-hook} hooks in that order, but @emph{after} the
compiler is started. Use @code{inferior-sml-mode-hook} to set any
@code{comint} buffer-local configurations for SML mode you like.
@end defvr


@deffn Command switch-to-sml
Key: @kbd{C-c C-s}
@kindex @kbd{C-c C-s}

Switch from the SML buffer to the interaction buffer. By default point
will be placed at the end of the process buffer, but a prefix argument
will leave point wherever it was before. If you try @kbd{C-c C-s} before
an ML process has been started, you'll just get an error message to the
effect that there's no current process buffer.
@end deffn


@deffn Command sml-cd
When started, the ML compiler's default working directory is the
current buffer's default directory. This command allows the working
directory to be changed, if the compiler can do this. The variable
@code{sml-cd-command} specifies the compiler command to invoke
(@pxref{Process Defaults}).
@end deffn


@c ======================================================== SENDING TEXT

@node ML Interaction, Tracking Errors, Running ML, Interaction Mode

@section Speaking to the compiler

@c == ML Interaction, Tracking Errors, Running ML, Interaction Mode ====


@noindent
Several commands are defined for sending program fragments to the
running compiler. Each of the following commands takes a prefix argument
that will switch the input focus to the process buffer afterwards
(leaving point at the end of the buffer):


@deffn Command sml-load-file
Key: @kbd{C-c C-l}
@kindex @kbd{C-c C-l}

Send a `use file' command to the current ML process. The variable
@code{sml-use-command} is used to define the correct template for the
command to invoke (@pxref{Process Defaults}). The default file is the
file associated with the current buffer, or the last file loaded if you
are in the interaction buffer.
@end deffn



@deffn Command sml-send-region
@findex sml-send-region-and-go
Key: @kbd{C-c C-r}
@kindex @kbd{C-c C-r}

Send the current region of text in the SML buffer.
@code{sml-send-region-and-go} is a similar command for you to bind in
SML mode if you wish: it'll send the region and then switch-to-sml.
@end deffn

@c @deffn Command sml-send-function
@c @findex sml-send-function-and-go

@c Send the enclosing `function' definition. Contrary to the suggestive
@c name, this command @emph{does not} try to determine the extent of the
@c function definition because that is too difficult with ML. Instead
@c this just sends the enclosing @emph{paragraph} (delimited by blank
@c lines or form-feed characters).
@c @end deffn

@deffn Command sml-send-buffer
Key: @kbd{C-c C-b}
@kindex @kbd{C-c C-b}

Send the contents of the current buffer to ML.
@end deffn

@c ===================================================== TRACKING ERRORS

@node Tracking Errors, Process Defaults, ML Interaction, Interaction Mode

@section Finding errors

@c == Tracking Errors, Process Defaults, ML Interaction, Interaction Mode


@noindent
SML mode provides one customisable function for locating the source
position of errors reported by the compiler. This should work whether
you type @code{use "puzzle.sml";} into the interaction buffer, or use
one of the mechanisms provided for sending programs directly to the
compiler---@pxref{ML Interaction}.


@deffn Command next-error
@findex next-error
Key: @kbd{C-x`}
@kindex @kbd{C-x`}

Jump to the source location of the next error reported by the compiler.
All the usual error-navigation commands are available, see
@pxref{Compilation Mode, , , emacs, The Emacs Editor Manual}.
@end deffn


@c ==================================================== PROCESS DEFAULTS

@node Process Defaults, , Tracking Errors, Interaction Mode

@section Process defaults

@c == Process Defaults, , Tracking Errors, Interaction Mode ============

@noindent
The process interaction code is independent of the compiler used,
deliberately, so SML mode will work with a variety of ML compilers
and ML-based tools. There are therefore a number of variables that may
need to be set correctly before SML mode can speak to the compiler.
Things are by default set up for Standard ML of New Jersey, but
switching to a new system is quite easy.



@defvar sml-use-command
Default: @code{"use \"%s\""}

Use file command template. Emacs will replace the @code{%s} with a file
name. Note that Emacs requires double quote characters inside strings
to be quoted with a backslash.
@end defvar


@defvar sml-cd-command
Default: @code{"OS.FileSys.chDir \"%s\""}

Compiler command to change the working directory. Not all ML systems
support this feature (well, Edinburgh (core) ML didn't), but they
should.
@end defvar


@defvar sml-prompt-regexp
Default: @code{"^[-=>#] *"}

Matches the ML compiler's prompt: @file{comint} uses this for various
purposes.
@end defvar


To customise error reportage for different ML compilers you need to set
two further variables before @code{next-error} can be useful:


@defvar sml-error-regexp-alist

Alist that specifies how to match errors in compiler output.
Each elt has the form (REGEXP FILE-IDX LINE-IDX [COLUMN-IDX FILE-FORMAT...])
If REGEXP matches, the FILE-IDX'th subexpression gives the file name, and
the LINE-IDX'th subexpression gives the line number.  If COLUMN-IDX is
given, the COLUMN-IDX'th subexpression gives the column number on that line.
If any FILE-FORMAT is given, each is a format string to produce a file name to
try; %s in the string is replaced by the text matching the FILE-IDX'th
subexpression.
@end defvar


@c A typical way of (re)setting these variables correctly is to put
@c something in your @file{.emacs} file that resembles

@c @example
@c (setq sml-use-command "PolyML.use \"%s\"")
@c (setq sml-prompt-regexp "^[>#] *")
@c @end example

@c ======================================================= CONFIGURATION

@node Configuration, , Interaction Mode, Top

@chapter Configuration Summary

@c @footnote{@url{http://www.ahl.co.uk/}}
@c @footnote{@url{http://www.dina.kvl.dk/~sestoft/mosml.html}}

@noindent
This (sort of pedagogic) section gives more information on how to
configure SML mode: menus, key bindings, hooks and highlighting are
discussed, along with a few other random topics.

@menu
* Hooks::               Creating them
* Key Bindings::        Binding commands to keys
* Highlighting::        Syntax colouring
* Advanced Topics::     You may need to speak Emacs Lisp
@end menu


@c =============================================================== HOOKS

@node Hooks, Key Bindings, Configuration, Configuration

@section Hooks

@c == Hooks, Key Bindings, Configuration, Configuration ================


@noindent
One way to set SML mode variables (@pxref{SML Mode
Defaults,,Indentation Defaults}), and other defaults, is through the
@code{sml-mode-hook} in your @file{.emacs}. A simple example:

@lisp
(defun my-sml-mode-hook () "Local defaults for SML mode"
  (setq sml-indent-level 2)        ; conserve on horizontal space
  (setq words-include-escape t)    ; \ loses word break status
  (setq indent-tabs-mode nil))     ; never ever indent with tabs
(add-hook 'sml-mode-hook 'my-sml-mode-hook)
@end lisp
@noindent
The body of @code{my-sml-mode-hook} is a sequence of assignments. In this
case it is not really necessary to set @code{sml-indent-level} in a hook
because this variable is global (most SML mode variables are). With
similar effect:

@lisp
(setq sml-indent-level 2)
@end lisp
@noindent
anywhere in your @file{.emacs} file. The variable @code{indent-tabs-mode} is
automatically made local to the current buffer whenever it is set
explicitly, so it @emph{must} be set in a hook if you always want
SML mode to behave like this.

Another hook is @code{inferior-sml-mode-hook}. This can be used to
control the behaviour of the interaction buffer through various
variables meaningful to @file{comint}-based packages:

@lisp
(defun my-inf-sml-mode-hook () "Local defaults for inferior SML mode"
  (add-hook 'comint-output-filter-functions 'comint-truncate-buffer)
  (setq      comint-scroll-show-maximum-output t)
  (setq      comint-input-autoexpand nil))
(add-hook 'inferior-sml-mode-hook 'my-inf-sml-mode-hook)
@end lisp
@noindent
Again, the body is a sequence of assignments. Unless you run several ML
compilers simultaneously under one Emacs, this hook will normally only
get run once. You might want to look up the documentation (@kbd{C-h v}
and @kbd{C-h f}) for these buffer-local @code{comint} things.


@c ======================================================== Key Bindings

@node Key Bindings, Highlighting, Hooks, Configuration

@section Key bindings

@noindent
Customisation (in Emacs) usually entails putting favourite commands on
easily remembered keys. Two `keymaps' are defined in SML mode: one
is effective in program text buffers (@code{sml-mode-map}) and the other
is effective in interaction buffers (@code{inferior-sml-mode-map}).
The initial design ensures that (many of) the default key bindings from
the former keymap will also be available in the latter (e.g.,
@kbd{C-c`}).

Type @kbd{C-h m} in an SML mode buffer to find the default key
bindings (and similarly in an ML interaction buffer), and use the hooks
provided to install your preferred key bindings. Given that the keymaps
are global (variables):

@lisp
(defun my-sml-mode-hook () "Global defaults for SML mode"
  (define-key sml-mode-map "\C-cd" 'sml-cd))
(add-hook 'sml-mode-hook 'my-sml-mode-hook)
@end lisp
@noindent
This has the effect of binding @code{sml-cd} to the key @kbd{C-c d}.
If you want the same behaviour from @kbd{C-c d} in the ML buffer:

@lisp
(defun my-inf-sml-mode-hook () "Global defaults for inferior SML mode"
  (define-key inferior-sml-mode-map "\C-cd" 'sml-cd)
  ;; NB. for SML/NJ '96
  (setq sml-cd-command "OS.FileSys.chDir \"%s\""))
(add-hook 'inferior-sml-mode-hook 'my-inf-sml-mode-hook)
@end lisp

There is nothing to stop you rebuilding the entire keymap for
SML mode and the ML interaction buffer in your @file{.emacs} of
course: SML mode won't define @code{sml-mode-map} or
@code{inferior-sml-mode-map} if you have already done so. 


@c ======================================================== Highlighting

@node Highlighting, Advanced Topics, Key Bindings, Configuration

@section Syntax colouring


@noindent
Highlighting is very handy for picking out keywords in the program text,
spotting misspelled kewyords, and, if you have Emacs' @file{ps-print}
package installed (you usually do these days), obtaining pretty, even
colourful code listings---quite properly for your colourful ML programs.

The indentation scheme (strangely enough) also relies on the
highlighting code to properly handle nested comments, which is yet
another reason to turn on highlighting.  To turn on highlighting,
use either of:

@lisp
M-x font-lock-mode
(add-hook 'sml-mode-hook 'turn-on-font-lock)
(global-font-lock-mode 1)
@end lisp

The first will turn it on in the current buffer.
The second will turn it on in all sml-mode buffers.
The last will turn it on everywhere.
This is valid for Emacs but maybe not for XEmacs.  Check font-lock
documentation if you encounter problems.

@c ===================================================== ADVANCED TOPICS

@node Advanced Topics, , Highlighting, Configuration

@section Advanced Topics

@flushright
@emph{These forms are bloody useless; can't we have better ones?}
@end flushright

@sp 1
@noindent
You can indeed. @code{sml-insert-form} is extensible so all you need to
do is create the macros yourself. Define a @emph{keybord macro}
(@kbd{C-x (} <something> @kbd{C-x )}) and give it a suitable name:
@code{sml-addto-forms-alist} prompts for a name, say @code{NAME}, and
binds the macro @code{sml-form-NAME}. Thereafter @kbd{C-c @key{RET}
NAME} will insert the macro at point, and @kbd{C-u C-c @key{RET} NAME}
will insert the macro after a @code{newline-and-indent}. If you want to
keep your macros from one editing session to the next, go to your
@file{.emacs} file and call @code{insert-kbd-macro}; you'll need
to add @code{NAME} to @code{sml-forms-alist} permanently yourself:

@lisp
(defun my-sml-mode-hook () "Global defaults for SML mode"
  ;; whatever else you do
  (add-to-list 'sml-forms-alist '("NAME" . FUNCTION)))
@end lisp

If you want to create templates like `case' that prompt for parameters
you'll have to do some Lisp programming. The @code{skeleton} package is
a good stating point.  Better yet, you can reuse the wrappers used by
sml-mode itself in your sml-mode-hook:

@lisp
(add-hook 'sml-mode-hook
  (lambda ()
    (sml-def-skeleton "case" "Case expr: "
      str " of" \n _ " => ")))
@end lisp

This will redefine `case' in order to leave the `of' on the first line.
See the documentation of @code{skeleton-insert} to get a better
understanding of how this works.

@sp 1
@flushright
@emph{I hate that indentation algorithm; can't I tweak it?}
@end flushright

@sp 1
@noindent
Ah, yes, of course, but this manual will not tell you how.


@sp 1
@flushright
@emph{Can SML mode handle more than one compiler running at once?}
@end flushright

Sure, just rename the @samp{*sml*} buffer and then use @code{run-sml}
as usual.

@sp 1
@flushright
@emph{What needs to be done to support other ML compilers?}
@end flushright

@sp 1
@noindent
Not much really.  Just add the right regular expressions to
@code{sml-error-regexp-alist} and that should be all.


@c ======================================================= COMMAND INDEX

@headings singleafter

@node Command Index, Variable Index, , Top

@unnumbered Command Index

@printindex fn

@c ====================================================== VARIABLE INDEX

@c node Variable Index, , Command Index, Top
@node Variable Index, Key Index, Command Index, Top

@unnumbered Variable Index

@c == Variable Index, Key Index, Command Index, Top ====================

@printindex vr

@c =========================================================== KEY INDEX

@node Key Index, , Variable Index, Top

@unnumbered Key Index

@c == Key Index, , Variable Index, Top =================================

@printindex ky

@contents
@bye