I need to implement some new functions on an editor. I picked Emacs - although my main programming knowledge is in Java and C - and I want to add some functions and edit some existing functions of Emacs Editor. I looked at the source code of it and I'm a bit lost. I was wondering whether anyone can give me some advice about where to start and whether there are any tutorials that can help?
P.S. One specific question would be how one can start to write a new mode with all new features and behaviour? or how I can disable some basic functions like copy/paste?
Cheers
An Introduction to Programming in Emacs Lisp http://www.gnu.org/software/emacs/emacs-lisp-intro/ or type in emacs:
M-: (info "(eintr)Top") RET
Emacs Lisp Manual http://www.gnu.org/software/emacs/manual/elisp.html or type in emacs:
M-: (info "(elisp)Top") RET
There are some tutorials out there specifically geared towards writing a major mode.
emacs extension guide [pdf]
how to write a major mode...
Other than that, writing modes in Emacs is just writing Lisp functions.
One thing I will note is that what you're proposing to do here may be pointless; if you implement a permission system as a major mode, a user can simply switch modes to turn it off. That's fine if the point of this permission system is to avoid clobbering edits (in which case I assume your users will cooperate with your aims). If you're expecting your users to be adversarial, then Emacs is the wrong tool for this.
Here is the manual section on defining major and minor modes:
C-hig (elisp) Modes RET
It is often beneficial to derive a new mode from an existing one which provides similar basic functionality to what you need.
If there's nothing which matches closely enough, examining the source code for modes which provide some of the same behaviour would be the next best thing.
I note that 'deriving' a mode from nil seems to be the common way of creating a completely new major mode. That way you still get all the benefits of the define-derived-mode macro.
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I am about to learn Emacs, have been through the tutorial and borrowed the O'Reilly book on Emacs. But the question still is - how do you learn good Emacs workflow? I guess, you don't use Emacs as you'd use, for example, Vim.
This question seems revelant to mine:
- Where can I find a video of a professional using Emacs?
I can't believe nobody has mentioned this, but reading the info pages bundled with Emacs is a great way to learn about obscure features. Whenever you need a break from coding, hit M-x info and pick a random page to read. Your emacs ability will improve incredibly quickly.
It is also important to realize how emacs' self-documenting-ness helps you work. Say, for example, you are wondering how you can scale the font size. Instead of interrupting your flow and asking here, or on IRC, or Google, you can ask emacs! Just hit C-h a (M-x command-apropos) and type a search term, in our case scale. If there are matching functions, their names, keybindings, and documentation will appear. There are, and now you've just discovered text-scale-increase and text-scale-decrease.
There are other self-documentation functions that are good to learn C-h m will tell you what keybindings and commands are available in the current major and minor modes. This is a great way to discover features you didn't know existed.
Another way to "learn by osmosis" is to M-x customize-group for the modes you use regularly. (customize is the interactive configuration editor that almost all modes support.)
The final thing to do is to learn Emacs Lisp. It is nice to use existing tools, but sometimes you will need your own. If you try to avoid learning Lisp, you will always be stuck with things not quite working right, and that's a shame.
Emacs is a great environment for customizing itself. Emacs includes two Lisp manuals that are viewable via M-x info. It is self-documenting, so you can say C-h f or M-x describe-function to get the documentation for any function. You can even press TAB ENT to jump to the source code of that function, to see how it's implemented. This is great when you think "I wish I had something that worked like foo, but just slightly different." You can read how foo is implemented, make your change in the *scratch* buffer, and then see if you like the change. There is no edit/compile/test cycle. You press a key and your emacs session immediately has the feature you just wrote.
The more effort you put into learning emacs, the more emacs will do to make your work easier.
Once you mastered the basics (opening/closing files, navigating, basic editing) just use it. As with a lot of other tools, practise makes perfect...
I would, however, set some time aside to work on improving how you use the editor currently, but as part of your normal workflow as opposed to just going off on a tangent and learning things for the sake of it.
I find some useful resources are the EmacsWiki and the Planet Emacsen blog. I use both, mainly by using Planet Emacsen for "inspiration" and then wandering over to EmacsWiki and having a trawl on there for a specific topic. I found that unless you're having at least a vague idea what you're looking for, the available information is just going to swamp you instead of it actually being helpful.
Not to mention that there are a few very useful resources here on StackOverflow, for example this question here. Emacs is a very powerful tool that tends to be able to do a lot more than a single person needs, but in the end that allows you to pick and choose exactly those parts that you need.
My suggestion is just stop using anything but Emacs, when you come across a problem see if you can solve it in Emacs, and then fall back (if you don't have the time or it just won't work). As for work flow, it is pretty much the same as you would normally work. i.e. for a normal ide session you would open/edit a file as normal, then commit (in C-x v v) just as normal.
I agree with the other posters here, you just have to use it! Here's how I did it:
Once I got the very basics (can get between buffers, open/save files, etc), I printed out a reference card and kept it handy. This is a good one. Review it just so you know what is on it, then whenever you find yourself doing something repeatedly that is on the card, start using the shortcut! Before you know it you'll have memorized quite an arsenal of commands. But remember, probably no one uses everything that emacs can do.
When you eventually find yourself doing something repeatedly that doesn't have a shortcut, that's a good time to learn keyboard macros. Once you get them, you'll find uses for them everywhere! From there it's a short jump to writing elisp (if you're a programmer).
The great thing about emacs is that you don't need an "emacs workflow", emacs works around your workflow!
You don't need to learn emacs workflow. Once you complete the tutorial and master the essentials, you'll have to adopt some degree of monogamy and use nothing but Emacs. Eventually you will think of functionality that you really wished existed; most of the time somebody else will have as well and the solution is just one search away! Over time you just can't help but learn and eventually you'll pick up enough that you'll develop your own personal workflow.
If you're looking to accelerate the process, the Emacs wiki has a variety of tips but really the best way is just to do stuff with Emacs.
You could have a look at Bram Molenaar's talk about efficient textediting, http://video.google.com/videoplay?docid=2538831956647446078&ei=EqiGSau8KZ-QiQLi-Nn8Cg&q=bram+molenaar+editing
Although he's a vim guy (he wrote it), you might get some ideas about how best to go about becoming more proficient with your text editor that'll apply to emacs.
To be honest, all I do is learn the keybindings I need. I don't use emacs to its full potential, because I don't need its full potential. My suggestion is to just learn what you need, and don't worry about what you don't. Learn a new key binding everyday, and in about 300 years will you know them all ;)
I am using the emacs since the old Amiga days on all platforms i am currently working on.
The best way to use emacs is curiosity. I still use often apropos (C-h a) and M-x (for a long functionname instead of key-binding) to find a functionality.
a key-concept to "proper use" Emacs is, to learn the very easy elisp (a simple derivate of lisp) and write your own little helpers (own commenting style, underlining, templates) and to know where to look to change values (tab-size, compiler, email)
And the third thing: everything is in emacs: I use the dired (directory editor) for navigating through files. I use a lot of buffers for all textual files (with proper modes for each type of file (c, ruby, list, sql, latex, ...)) which are stored when quitting emacs and recovered when invoking. I start the compiler from emacs and use the jump-to-error-functionality.
Macros are a daily routine (scimming throu code and changing it on the way).
I like the picture-mode, which allows to type downward with replacing, which makes it easy to renumber block of constants (good old c #defines))
There is a hugh mountain to climb, but if you have reached the top, you can see the whole world down your feet, and never want to miss this experience again. I know, there are many good editors around (i work myself thru Eclipse)
As previously stated, the best advice is to use nothing but Emacs for the next year. Once you develop your finger memory, things get to be much easier.
How do you learn a "good workflow" for anything? By using it, getting to know it, making it yours. There is no "proper" use of Emacs.
As for getting to know it: ask Emacs -- use its help system. This can help too: http://www.emacswiki.org/emacs/EmacsNewbieWithIcicles
That's the power of Emacs, you use it the way you like. You just have to configure it before for your liking.
I am not particularly satisfied how the viper mode works in Emacs. I am trying to write my own viper mode. I do not have any good programming experience in Elisp except for the number of customizations I have done using the .emacs file.
I would like to know if I can change the key-bindings in Emacs temporarily and return them back to their original state as and when needed.
Well if I understand your question correctly one easy way to do this would be to create your own minor mode (in addition to your own specific mode I'd say), made only of your temporary key-bindings.
You give a name to that mode and then toggling all your temporary key-bindings on or off becomes as simple as calling your command:
M-x salsabear-minor-mode
You probably want to read scottfrazer's 45+ upvotes answer here on SO:
Globally override key binding in Emacs
where he explains how to create your own minor-mode containing your key-bindings.
Given that you explicitly only mention viper, it's probably worth asking whether you're aware of the other vi/vim-based libraries which exist? See the list under:
http://www.emacswiki.org/emacs/CategoryEmulation
I would suspect that re-inventing this particular wheel is probably not worthwhile.
I believe that Evil is the most active project, but if it doesn't work the way you want, your efforts might be better-spent enhancing that (if practical)?
I just started to use the tuareg mode in emacs for ocaml programming. So can someone tell me what are the main advantages of using it? Can someone suggest me any tutorial for that?
Tuareg-mode is good because it can parse code and calculate indentation & font-lock basing on this information. Plus it provides pretty good possibilities to interactive work with code.
Regarding tutorial - I don't think that such exists (although I planned to write it long time ago). All information for installation is in README file, and you can learn about available commands by visiting file with OCaml source code, and pressing C-h m to get description of mode, or by getting description of tuareg-mode function (if tuareg.el is loaded already).
Useful addition to these descriptions is Tuareg mode refcard that lists all (or almost) available commands.
Tuareg is really nice for:
Highlighting your code
Indenting your code correctly
Easily sending portions of code to a REPL
Easily compiling your code
Syntax highlight, indentation, as (almost) all language modes.
Compile or evaluate in a top level from a single buffer (you no longer need to open a ocaml toplevel in a command line to test some crap functions)
Caml-types minor mode : after a successful or partial compilation, you can easily point a variable and get the type the compiler inferred for it.
In visual studio it 's easier to push F12 button to jump to a declaration of a function or variable when editing C/C++ code.
Is there a short-cut key in emacs to do that?
Well, it's a bit more involved than that.
By default, Emacs doesn't "know" about function declarations for C or C++ code. First, obtain Exuberant Ctags. Then, use command etags (ctags for Emacs) on your source code. A file named TAGS will be generated.
Then, while editing your source code, when you want to jump to a declaration, press M-. (meta and dot, or alt and dot on modern keyboards). At first, Emacs will ask you for location of your tags file. Point it to the one you generated and afterwards navigation will be automatic.
I'd suggest reading Emacswiki article about tags for a better understanding of this functionality.
The newest version of Emacs (23.2) comes with CEDET integrated, which has more advanced features for C and C++ navigation, but it can be a bit difficult to set up right, so read more about it if you're interested.
M-. key will take you to the function definition emacs.
As others have said there is no built-in universal solution for this in emacs. That said, after having this functionality in IntelliJ I wanted it in emacs too so I made Dumb Jump.
Right now Dumb Jump has basic support for:
JavaScript
Emacs Lisp
Python
Go
PHP
Ruby
Faust
and more... (over 20 now)
It's available via MELPA and is actively being developed.
There are multiple ways to do this. As darioo mentioned, Ctags is one, but it goes to the definition by default (which might work for you). Looking further, though, you can see that prefixing M-.(ie, C-u M-.) will take you to the next tag match (which is often the declaration). There is also a --declarations option, but Exuberant Ctags doesn't seem to support it.
CEDET is another option, but in my experience, it's still not ready for production. Often times in C++ semantic-ia-fast-jump will go to forward declarations instead of the definition or the declaration.
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I am about to learn Emacs, have been through the tutorial and borrowed the O'Reilly book on Emacs. But the question still is - how do you learn good Emacs workflow? I guess, you don't use Emacs as you'd use, for example, Vim.
This question seems revelant to mine:
- Where can I find a video of a professional using Emacs?
I can't believe nobody has mentioned this, but reading the info pages bundled with Emacs is a great way to learn about obscure features. Whenever you need a break from coding, hit M-x info and pick a random page to read. Your emacs ability will improve incredibly quickly.
It is also important to realize how emacs' self-documenting-ness helps you work. Say, for example, you are wondering how you can scale the font size. Instead of interrupting your flow and asking here, or on IRC, or Google, you can ask emacs! Just hit C-h a (M-x command-apropos) and type a search term, in our case scale. If there are matching functions, their names, keybindings, and documentation will appear. There are, and now you've just discovered text-scale-increase and text-scale-decrease.
There are other self-documentation functions that are good to learn C-h m will tell you what keybindings and commands are available in the current major and minor modes. This is a great way to discover features you didn't know existed.
Another way to "learn by osmosis" is to M-x customize-group for the modes you use regularly. (customize is the interactive configuration editor that almost all modes support.)
The final thing to do is to learn Emacs Lisp. It is nice to use existing tools, but sometimes you will need your own. If you try to avoid learning Lisp, you will always be stuck with things not quite working right, and that's a shame.
Emacs is a great environment for customizing itself. Emacs includes two Lisp manuals that are viewable via M-x info. It is self-documenting, so you can say C-h f or M-x describe-function to get the documentation for any function. You can even press TAB ENT to jump to the source code of that function, to see how it's implemented. This is great when you think "I wish I had something that worked like foo, but just slightly different." You can read how foo is implemented, make your change in the *scratch* buffer, and then see if you like the change. There is no edit/compile/test cycle. You press a key and your emacs session immediately has the feature you just wrote.
The more effort you put into learning emacs, the more emacs will do to make your work easier.
Once you mastered the basics (opening/closing files, navigating, basic editing) just use it. As with a lot of other tools, practise makes perfect...
I would, however, set some time aside to work on improving how you use the editor currently, but as part of your normal workflow as opposed to just going off on a tangent and learning things for the sake of it.
I find some useful resources are the EmacsWiki and the Planet Emacsen blog. I use both, mainly by using Planet Emacsen for "inspiration" and then wandering over to EmacsWiki and having a trawl on there for a specific topic. I found that unless you're having at least a vague idea what you're looking for, the available information is just going to swamp you instead of it actually being helpful.
Not to mention that there are a few very useful resources here on StackOverflow, for example this question here. Emacs is a very powerful tool that tends to be able to do a lot more than a single person needs, but in the end that allows you to pick and choose exactly those parts that you need.
My suggestion is just stop using anything but Emacs, when you come across a problem see if you can solve it in Emacs, and then fall back (if you don't have the time or it just won't work). As for work flow, it is pretty much the same as you would normally work. i.e. for a normal ide session you would open/edit a file as normal, then commit (in C-x v v) just as normal.
I agree with the other posters here, you just have to use it! Here's how I did it:
Once I got the very basics (can get between buffers, open/save files, etc), I printed out a reference card and kept it handy. This is a good one. Review it just so you know what is on it, then whenever you find yourself doing something repeatedly that is on the card, start using the shortcut! Before you know it you'll have memorized quite an arsenal of commands. But remember, probably no one uses everything that emacs can do.
When you eventually find yourself doing something repeatedly that doesn't have a shortcut, that's a good time to learn keyboard macros. Once you get them, you'll find uses for them everywhere! From there it's a short jump to writing elisp (if you're a programmer).
The great thing about emacs is that you don't need an "emacs workflow", emacs works around your workflow!
You don't need to learn emacs workflow. Once you complete the tutorial and master the essentials, you'll have to adopt some degree of monogamy and use nothing but Emacs. Eventually you will think of functionality that you really wished existed; most of the time somebody else will have as well and the solution is just one search away! Over time you just can't help but learn and eventually you'll pick up enough that you'll develop your own personal workflow.
If you're looking to accelerate the process, the Emacs wiki has a variety of tips but really the best way is just to do stuff with Emacs.
You could have a look at Bram Molenaar's talk about efficient textediting, http://video.google.com/videoplay?docid=2538831956647446078&ei=EqiGSau8KZ-QiQLi-Nn8Cg&q=bram+molenaar+editing
Although he's a vim guy (he wrote it), you might get some ideas about how best to go about becoming more proficient with your text editor that'll apply to emacs.
To be honest, all I do is learn the keybindings I need. I don't use emacs to its full potential, because I don't need its full potential. My suggestion is to just learn what you need, and don't worry about what you don't. Learn a new key binding everyday, and in about 300 years will you know them all ;)
I am using the emacs since the old Amiga days on all platforms i am currently working on.
The best way to use emacs is curiosity. I still use often apropos (C-h a) and M-x (for a long functionname instead of key-binding) to find a functionality.
a key-concept to "proper use" Emacs is, to learn the very easy elisp (a simple derivate of lisp) and write your own little helpers (own commenting style, underlining, templates) and to know where to look to change values (tab-size, compiler, email)
And the third thing: everything is in emacs: I use the dired (directory editor) for navigating through files. I use a lot of buffers for all textual files (with proper modes for each type of file (c, ruby, list, sql, latex, ...)) which are stored when quitting emacs and recovered when invoking. I start the compiler from emacs and use the jump-to-error-functionality.
Macros are a daily routine (scimming throu code and changing it on the way).
I like the picture-mode, which allows to type downward with replacing, which makes it easy to renumber block of constants (good old c #defines))
There is a hugh mountain to climb, but if you have reached the top, you can see the whole world down your feet, and never want to miss this experience again. I know, there are many good editors around (i work myself thru Eclipse)
As previously stated, the best advice is to use nothing but Emacs for the next year. Once you develop your finger memory, things get to be much easier.
How do you learn a "good workflow" for anything? By using it, getting to know it, making it yours. There is no "proper" use of Emacs.
As for getting to know it: ask Emacs -- use its help system. This can help too: http://www.emacswiki.org/emacs/EmacsNewbieWithIcicles
That's the power of Emacs, you use it the way you like. You just have to configure it before for your liking.