Emacs and C++ - c++

Once again it is time to clean up my emacs setup. Before I go cleaning it up, are there any packages that you would recommend above and beyond c++-mode, cedet, ecb, speedbar etc. ? Especially stuff that's new in the last five years.

This could be helpful!

I use msf-abbrevs package for inserting code snippets as i type special code words - something like for, if, etc, but with highliting of positions, that should be filled out, and moving between them with TAB key

You might like some of the stuff I added for C programming including splint, cdecl, scons support in making projects and xcscope.
http://richardriley.net/default/projects/emacs/dotprogramming

Related

Change indentation with Emacs minor mode

I have a CS class that requires (or at least strongly suggests) 8 spaces for C++ indentation. I normally use 2, so this is quite different for me.
I have until recently been just toggling the indent code in my .emacs and running eval-buffer, but that seems like a poor solution with a programmable editor.
So I am wondering: how might I go about creating a minor Mode (or is there a better function for this?)? I'd like to be able to enable it with M-x comp-mode or something similar.
I have seen minor modes, but they seem to instead focus on key mappings. Perhaps I am looking at the wrong Emacs feature.
Perhaps I can extend the C++ mode to create a comp-mode with different indentation settings?
You could probably do this with a minor mode, but an easier solution is to use directory variables. Create a file called .dir-locals.el in the directory containing your coursework and put something like this in it:
((c++-mode . ((indent-tabs-mode . nil)
(c-basic-offset . 8))))

How can I highlight different types of file in dired mode in Emacs?

In a nutshell, I want to have different faces for some types of file in dired mode. I don't think it matters, but I am using Aquamacs.
The example I will use here is .tex files. If I can do it for .tex, then I can just apply the same structure to do create other faces for other types of files.
From what I understand, I have to create a variable, write a regular expression, then apply a hook. I read a bit about regex and so far I have
^(.+)\.tex$
I think my structure and regular expression are not really correct. I am not a programmer (though I have an interest on it), I have only been using Emacs for 2 weeks or so, so any help would be greatly appreciated.
What I need is at least the basic structure of what I have to do. I understand there may be modes already created that do something similar (such as maybe Wdired and Dired-X), and I would not complain if someone told me about them, but what I really want is to have an elisp code (either already written or that I can work on), as I plan on learning a bit of elisp to be able to write my own customisations and this would be a way to learn.
Thank you!
Since you want to learn how to do it, try checking out the extension dired+.el. This mode does a lot more than what you want, but it does add new faces. Specifically, look for the variable diredp-font-lock-keywords-1 and how it is used. That should get you going.
Other SO questions that seem relevant are:
Match regular expression as keyword in define-generic-mode
Highlighting correctly in an emacs major mode
A hello world example for a major mode in emacs?

How can I refactor C++ source code using emacs?

I'm interested mostly in C++ and method/class name/signature automatic changes.
In recent Emacs versions (24), Semantic is able to this.
Possibly activate semantic mode M-x semantic-mode RET.
Bring up the Symref buffer with C-c , g.
Press C-c C-e to open all references.
Rename with R.
If you can program in elisp, you can look to combination of cedet + srecode from CEDET libraries - it provide all instruments for this task - find callers of functions, get signature, etc. But you need to create refactory tool yourself, using these instruments
I do this a lot, so I'm axiously awaiting other replies too.
The only tricks I know are really basic. Here are my best friends in Emacs when refactoring code:
M-x query-replace
This allows you to do a global search and replace. You'll be doing this a ton when you move methods and commonly-accessed data to other classes or namespaces.
C-x 3
This gives you a display with two buffers side-by side. You can then proceed to load different files in them, and move your cursor from one to the other with C-x o. This is pretty basic stuff, but I mention it because of how powerful it makes the next one...
C-x (
(type any amount of stuff and/or emacs commands here)
C-x )
This is how you define a macro in emacs. Any time you find yourself needing to do the same thing over and over to a bunch of code (and it is too complex for query-replace), this is a lifesaver. If you mess up, you can hit C-g to stop the macro definition, and then undo (C-_) until you are back to where you started. The keys to invoke the macro are C-x e. If you want to do it a bunch of times, you can hit Esc and type in a number first. Eg: Esc 100 C-x e will try to invoke your macro 100 times.
(Note: On Windows you can get "Meta" by hitting the Esc key, or holding down Alt).
The current (2022) state of the art is, I would say, using emacs lsp-mode with a suitable language server.
With the clangd or ccls, which provide the "language server protocol" (lsp) and connect to lsp-mode, you can refactor names with:
M-x lsp-rename
To simplify this setup, I'd recommend using Spacemacs with c-c++ and lsp layers (and using clangd).
For somewhere in between refactoring tools and simple regex, since Emacs 22 you can embed arbitrary elisp expressions in your replacement text, which allows you to do incredibly powerful text manipulation. Steve Yegge wrote a good article on this a while ago.
A friend of mine was playing with xrefactory and said it worked pretty well. It isn't cheap though.
Build cscope symbols.
lookup the symbol you want to refactor.
get into the cscope window, and start a macro after placing cursor on first occurence
ret
c-f your symbol start
navigate to start of your symbol
modify the word
c-x o (back to cscope)
n (for next cscope symbol)
you have to just c-x c-e now
I totally agree that find-and-replace work fine. However , a really nice feature of cedet is 'semantic-symref-list'.
With the cursor on a method, run this command, and you will be presented with a buffer that lists all of the places in your code that reference this tag.
You can still use find-and-replace tricks, and this will confirm that you have changed all the references.
I've been using cquery for my C++ completion which uses Microsoft LSP for IDE <-> Tool communication. cquery server satisfies the requests of the LSP protocol using a clang backend.
lsp-emacs is the package that sits between emacs and the cquery backend (cquery-emacs) which exposes an lsp-rename function. As a completion system, cquery has been very reliable and fast by the way, highly recommended.
Give it a try, follow the getting-started guide on the cquery github:
https://github.com/cquery-project/cquery/wiki/Emacs
Once you've got cquery setup:
Hover your cursor over an identifier (class, var, whatever) you'd like to rename.
M-x lsp-rename
Enter the new name for the identifier.
Do C-x s (save some buffers), which will prompt you to save
all the buffers that were touched by the refactor.
You should probably go through all modified buffers and check what was done after refactoring with any tool/language.

C++ vim IDE. Things you'd need from it

I was going to create the C++ IDE Vim extendable plugin. It is not a problem to make one which will satisfy my own needs.
This plugin was going to work with workspaces, projects and its dependencies.
This is for unix like system with gcc as c++ compiler.
So my question is what is the most important things you'd need from an IDE? Please take in account that this is Vim, where almost all, almost, is possible.
Several questions:
How often do you manage different workspaces with projects inside them and their relationships between them? What is the most annoying things in this process.
Is is necessary to recreate "project" from the Makefile?
Thanks.
Reason to create this plugin:
With a bunch of plugins and self written ones we can simulate most of things. It is ok when we work on a one big "infinitive" project.
Good when we already have a makefile or jam file. Bad when we have to create our owns, mostly by copy and paste existing.
All ctags and cscope related things have to know about list of a real project files. And we create such ones. This <project#get_list_of_files()> and many similar could be a good project api function to cooperate with an existing and the future plugins.
Cooperation with an existing makefiles can help to find out the list of the real project files and the executable name.
With plugin system inside the plugin there can be different project templates.
Above are some reasons why I will start the job. I'd like to hear your one.
There are multiple problems. Most of them are already solved by independent and generic plugins.
Regarding the definition of what is a project.
Given a set of files in a same directory, each file can be the unique file of a project -- I always have a tests/ directory where I host pet projects, or where I test the behaviour of the compiler. On the opposite, the files from a set of directories can be part of a same and very big project.
In the end, what really defines a project is a (leaf) "makefile" -- And why restrict ourselves to makefiles, what about scons, autotools, ant, (b)jam, aap? And BTW, Sun-Makefiles or GNU-Makefiles ?
Moreover, I don't see any point in having vim know the exact files in the current project. And even so, the well known project.vim plugin already does the job. Personally I use a local_vimrc plugin (I'm maintaining one, and I've seen two others on SF). With this plugin, I just have to drop a _vimrc_local.vim file in a directory, and what is defined in it (:mappings, :functions, variables, :commands, :settings, ...) will apply to each file under the directory -- I work on a big project having a dozen of subcomponents, each component live in its own directory, has its own makefile (not even named Makefile, nor with a name of the directory)
Regarding C++ code understanding
Every time we want to do something complex (refactorings like rename-function, rename-variable, generate-switch-from-current-variable-which-is-an-enum, ...), we need vim to have an understanding of C++. Most of the existing plugins rely on ctags. Unfortunately, ctags comprehension of C++ is quite limited -- I have already written a few advanced things, but I'm often stopped by the poor information provided by ctags. cscope is no better. Eventually, I think we will have to integrate an advanced tool like elsa/pork/ionk/deshydrata/....
NB: That's where, now, I concentrate most of my efforts.
Regarding Doxygen
I don't known how difficult it is to jump to the doxygen definition associated to a current token. The first difficulty is to understand what the cursor is on (I guess omnicppcomplete has already done a lot of work in this direction). The second difficulty will be to understand how doxygen generate the page name for each symbol from the code.
Opening vim at the right line of code from a doxygen page should be simple with a greasemonkey plugin.
Regarding the debugger
There is the pyclewn project for those that run vim under linux, and with gdb as debugger. Unfortunately, it does not support other debuggers like dbx.
Responses to other requirements:
When I run or debug my compiled program, I'd like the option of having a dialog pop up which asks me for the command line parameters. It should remember the last 20 or so parameters I used for the project. I do not want to have to edit the project properties for this.
My BuildToolsWrapper plugin has a g:BTW_run_parameters option (easily overridden with project/local_vimrc solutions). Adding a mapping to ask the arguments to use is really simple. (see :h inputdialog())
work with source control system
There already exist several plugins addressing this issue. This has nothing to do with C++, and it must not be addressed by a C++ suite.
debugger
source code navigation tools (now I am using http://www.vim.org/scripts/script.php?script_id=1638 plugin and ctags)
compile lib/project/one source file from ide
navigation by files in project
work with source control system
easy acces to file changes history
rename file/variable/method functions
easy access to c++ help
easy change project settings (Makefiles, jam, etc)
fast autocomplette for paths/variables/methods/parameters
smart identation for new scopes (also it will be good thing if developer will have posibility to setup identation rules)
highlighting incorrect by code convenstion identation (tabs instead spaces, spaces after ";", spaces near "(" or ")", etc)
reformating selected block by convenstion
Things I'd like in an IDE that the ones I use don't provide:
When I run or debug my compiled program, I'd like the option of having a dialog pop up which asks me for the command line parameters. It should remember the last 20 or so parameters I used for the project. I do not want to have to edit the project properties for this.
A "Tools" menu that is configurable on a per-project basis
Ability to rejig the keyboard mappings for every possible command.
Ability to produce lists of project configurations in text form
Intelligent floating (not docked) windows for debugger etc. that pop up only when I need them, stay on top and then disappear when no longer needed.
Built-in code metrics analysis so I get a list of the most complex functions in the project and can click on them to jump to the code
Built-in support for Doxygen or similar so I can click in a Doxygen document and go directly to code. Sjould also reverse navigate from code to Doxygen.
No doubt someone will now say Eclipse can do this or that, but it's too slow and bloated for me.
Adding to Neil's answer:
integration with gdb as in emacs. I know of clewn, but I don't like that I have to restart vim to restart the debugger. With clewn, vim is integrated into the debugger, but not the other way around.
Not sure if you are developing on Windows, but if you are I suggest you check out Viemu. It is a pretty good VIM extension for Visual Studio. I really like Visual Studio as an IDE (although I still think VC6 is hard to beat), so a Vim extension for VS was perfect for me. Features that I would prefer worked better in a Vim IDE are:
The Macro Recording is a bit error prone, especially with indentation. I find I can easily and often record macros in Vim while I am editing code (eg. taking an enum defn from a header and cranking out a corresponding switch statement), but found that Viemu is a bit flakey in that deptartment.
The VIM code completion picks up words in the current buffer where Viemu hooks into the VS code completion stuff. This means if I have just created a method name and I want to ctrl ] to auto complete, Vim will pick it up, but Viemu won't.
For me, it's just down to the necessities
nice integration with ctags, so you can do jump to definition
intelligent completion, that also give you the function prototype
easy way to switch between code and headers
interactive debugging with breaakpoints, but maybe
maybe folding
extra bonus points for refactoring tools like rename or extract method
I'd say stay away from defining projects - just treat the entire file branch as part of the "project" and let users have a settings file to override that default
99% of the difference in speed I see between IDE and vim users is code lookup and navigation. You need to be able to grep your source tree for a phrase (or intelligently look for the right symbol using ctags), show all the hits, and switch to that file in like two or three keystrokes.
All the other crap like repository navigation or interactive debugging is nice, but there are other ways to solve those problems. I'd say drop the interactive debugging even. Just focus on what makes IDEs good editors - have a "big picture" view of your project, instead of single file.
In fact, are there any plugins for vim that already achieve this?

C++ Directory Restructuring

I have a source code of about 500 files in about 10 directories. I need to refactor the directory structure - this includes changing the directory hierarchy or renaming some directories.
I am using svn version control. There are two ways to refactor: one preserving svn history (using svn move command) and the other without preserving. I think refactoring preserving svn history is a lot easier using eclipse CDT and SVN plugin (visual studio does not fit at all for directory restructuring).
But right now since the code is not released, we have the option to not preserve history.
Still there remains the task of changing the include directives of header files wherever they are included. I am thinking of writing a small script using python - receives a map from current filename to new filename, and makes the rename wherever needed (using something like sed). Has anyone done this kind of directory refactoring? Do you know of good related tools?
If you're having to rewrite the #includes to do this, you did it wrong. Change all your #includes to use a very simple directory structure, at mot two levels deep and only using a second level to organize around architecture or OS dependencies (like sys/types.h).
Then change your make files to use -I include paths.
Voila. You'll never have to hack the code again for this, and compiles will blow up instantly if something goes wrong.
As far as the history part, I personally find it easier to make a clean start when doing this sort of thing; archive the old one, make a new repository v2, go from there. The counterargument is when there is a whole lot of history of changes, or lots of open issues against the existing code.
Oh, and you do have good tests, and you're not doing this with a release coming right up, right?
I would preserve the history, even if it takes a small amount of extra time. There's a lot of value in being able to read through commit logs and understand why function X is written in a weird way, or that this really is an off-by-one error because it was written by Oliver, who always gets that wrong.
The argument against preserving the history can be made for the following users:
your code might have embarrassing things, like profanity and fighting among developers
you don't care about the commit history of your code, because it's not going to change or be maintained in the future
I did some directory refactoring like this last year on our code base. If your code is reasonable structured at the beginning, you can do about 75-90% of the work using scripts written in your language of choice (I used Perl). In my case, we were moving from set of files all in one big directory, to a series of nested directories depending on namespaces. So, a file that declared the class protocols::serialization::SerializerBase was located in src/protocols/serialization/SerializerBase. The mapping from the old name to the new name was trivial, so that doing a find and replace on #includes in every source file in the tree was trivial, although it was a big change. There were a couple of weird edge cases that we had to fix by hand, but that seemed a lot better than either having to do everything by hand or having to write our own C++ parser.
Hacking up a shell script to do the svn moves is trivial. In tcsh it's foreach F ( $FILES ) ... end to adjust a set of files. Perl & Python offer better utility.
It really is worth saving the history. Especially when trying to track down some exotic bug. Those who do not learn from history are doomed to repeat it, or some such junk...
As for altering all the files... There was a similar question just the other day over at:
https://stackoverflow.com/questions/573430/
c-include-header-path-change-windows-to-linux/573531#573531