Unfortunately, UNIX® systems do not come with the
kind of everything-you-ever-wanted-and-lots-more-you-did-not-in-one-gigantic-package
integrated development environments that other systems have. However, it is
possible to set up your own environment. It may not be as pretty, and it may not be quite
as integrated, but you can set it up the way you want it. And it is free. And you have
the source to it.
The key to it all is Emacs. Now there are some people who loathe it, but many who love
it. If you are one of the former, I am afraid this section will hold little of interest
to you. Also, you will need a fair amount of memory to run it--I would recommend 8MB in
text mode and 16MB in X as the bare minimum to get reasonable performance.
Emacs is basically a highly customizable editor--indeed, it has been customized to the
point where it is more like an operating system than an editor! Many developers and
sysadmins do in fact spend practically all their time working inside Emacs, leaving it
only to log out.
It is impossible even to summarize everything Emacs can do here, but here are some of
the features of interest to developers:
-
Very powerful editor, allowing search-and-replace on both strings and regular
expressions (patterns), jumping to start/end of block expression, etc, etc.
-
Pull-down menus and online help.
-
Language-dependent syntax highlighting and indentation.
-
Completely customizable.
-
You can compile and debug programs within Emacs.
-
On a compilation error, you can jump to the offending line of source code.
-
Friendly-ish front-end to the info program used for reading
GNU hypertext documentation, including the documentation on Emacs itself.
-
Friendly front-end to gdb, allowing you to look at the source
code as you step through your program.
-
You can read Usenet news and mail while your program is compiling.
And doubtless many more that I have overlooked.
Emacs can be installed on FreeBSD using the Emacs port.
Once it is installed, start it up and do C-h t to read an
Emacs tutorial--that means hold down the control key, press h, let go of the control key, and then press t. (Alternatively, you can you use the mouse to select from the
menu).
Although Emacs does have menus, it is well worth learning the key bindings, as it is
much quicker when you are editing something to press a couple of keys than to try to find
the mouse and then click on the right place. And, when you are talking to seasoned Emacs
users, you will find they often casually throw around expressions like ``M-x replace-s RET foo RET bar RET'' so it is useful to know what
they mean. And in any case, Emacs has far too many useful functions for them to all fit
on the menu bars.
Fortunately, it is quite easy to pick up the key-bindings, as they are displayed next
to the menu item. My advice is to use the menu item for, say, opening a file until you
understand how it works and feel confident with it, then try doing C-x C-f. When you are
happy with that, move on to another menu command.
If you can not remember what a particular combination of keys does, select from the menu
and type it in--Emacs will tell you what it does. You can also use the menu item to find out all the commands which
contain a particular word in them, with the key binding next to it.
By the way, the expression above means hold down the Meta
key, press x, release the Meta
key, type replace-s (short for replace-string--another feature of Emacs is that you can abbreviate
commands), press the return key, type foo (the string you want replaced), press the return key, type bar (the string you want to replace foo with) and press return again. Emacs
will then do the search-and-replace operation you have just requested.
If you are wondering what on earth the Meta key is, it is
a special key that many UNIX workstations have.
Unfortunately, PC's do not have one, so it is usually the alt key
(or if you are unlucky, the escape key).
Oh, and to get out of Emacs, do C-x C-c (that means hold down
the control key, press x, press
c and release the control key).
If you have any unsaved files open, Emacs will ask you if you want to save them. (Ignore
the bit in the documentation where it says C-z is the usual way
to leave Emacs--that leaves Emacs hanging around in the background, and is only really
useful if you are on a system which does not have virtual terminals).
Emacs does many wonderful things; some of them are built in, some of them need to be
configured.
Instead of using a proprietary macro language for configuration, Emacs uses a version
of Lisp specially adapted for editors, known as Emacs Lisp. Working with Emacs Lisp can
be quite helpful if you want to go on and learn something like Common Lisp. Emacs Lisp
has many features of Common Lisp, although it is considerably smaller (and thus easier to
master).
The best way to learn Emacs Lisp is to download the Emacs
Tutorial
However, there is no need to actually know any Lisp to get started with configuring
Emacs, as I have included a sample .emacs file, which should be
enough to get you started. Just copy it into your home directory and restart Emacs if it
is already running; it will read the commands from the file and (hopefully) give you a
useful basic setup.
Now, this is all very well if you only want to program in the languages already
catered for in the .emacs file (C, C++, Perl, Lisp and Scheme),
but what happens if a new language called ``whizbang'' comes out, full of exciting
features?
The first thing to do is find out if whizbang comes with any files that tell Emacs
about the language. These usually end in .el, short for ``Emacs
Lisp''. For example, if whizbang is a FreeBSD port, we can locate these files by
doing
% find /usr/ports/lang/whizbang -name "*.el" -print
and install them by copying them into the Emacs site Lisp directory. On FreeBSD
2.1.0-RELEASE, this is /usr/local/share/emacs/site-lisp.
So for example, if the output from the find command was
/usr/ports/lang/whizbang/work/misc/whizbang.el
we would do
# cp /usr/ports/lang/whizbang/work/misc/whizbang.el /usr/local/share/emacs/site-lisp
Next, we need to decide what extension whizbang source files have. Let's say for the
sake of argument that they all end in .wiz. We need to add an
entry to our .emacs file to make sure Emacs will be able to use
the information in whizbang.el.
Find the auto-mode-alist entry in .emacs and add a line for whizbang, such as:
...
("\\.lsp$" . lisp-mode)
("\\.wiz$" . whizbang-mode)
("\\.scm$" . scheme-mode)
...
This means that Emacs will automatically go into whizbang-mode when you edit a file ending in .wiz.
Just below this, you will find the font-lock-auto-mode-list
entry. Add whizbang-mode to it like so:
;; Auto font lock mode
(defvar font-lock-auto-mode-list
(list 'c-mode 'c++-mode 'c++-c-mode 'emacs-lisp-mode 'whizbang-mode 'lisp-mode 'perl-mode 'scheme-mode)
"List of modes to always start in font-lock-mode")
This means that Emacs will always enable font-lock-mode
(ie syntax highlighting) when editing a .wiz file.
And that is all that is needed. If there is anything else you want done automatically
when you open up a .wiz file, you can add a whizbang-mode hook (see my-scheme-mode-hook for a simple example that adds auto-indent).
