How to index C/C++ code using Emacs?
Is it possible to use Cscope db to browsing C/C++ code in emacs?
CEDET (built-in) does a good job for this.
Use http://alexott.net/en/writings/emacs-devenv/EmacsCedet.html
for an introduction to CEDET.
Use semantic-ia-fast-jump to go to definition of entity at point.
Use function-args or
helm-semantic
if you'd like to jump within a file with helm like so:
Related
I am trying to print the dependencies associated with a code, such as definitions related to functions or variables in a statement using Emacs, however I am not finding the functions necessary to do it. I have already been able to parse the code, now I just need the printing part, for which I have been looking into the srecode package without success.
It will be a necessary step to translate Java code into C or C++
What "code"? In what programming language? There are packages for different programming languages that could help. You need to be more specific.
to use emacs at this point perharps was a bad idea. I searched for code slicing and found some tools here: slicers. For the translation part I may use code from cogre-srecode.el from the cogre package of cedet and for it the manual of srecode is better
In Emacs, I can create functions in Lisp language and place them in .emacs file. Those function will become commands that can be called from the editor or bound to keys just like any other built-in command.
Is there a way to do that in VSCode?
Note: The custom commands need to be able to call other commands. Simply using a batch file and running it as a task will not work.
A few marketplace extensions may be of interest:
Script Commands by Marcel J. Kloubert
multi-command by ryuta46
However in general, you'll need to write an extension to do anything complex.
There's also a VS Code issue tracking support for built-in macros
There's Power Tools by e.GO:digital. It has support for custom commands and event triggers (ie. on file changed), among other things.
EMACS has the Meta . key binding for SLIME, which only works in a limited fashion for Common Lisp.
Is there a more general way to go to a function definition that works with Scheme? Perhaps something that searches through the sources like Cscope?
For Racket use racket-mode written by Greg Hendershott.
https://github.com/greghendershott/racket-mode
The documentation on racket-visit-definition to which M-. is bound.
Docs on racket-visit-documentation
Try Geiser. It's the equivalent of SLIME for Scheme. M-. is there as well.
You can generate the tags files yourself using etags (similar to ctags for vim). These should work in vanilla emacs (without slime):
etags *.scm
etags won't walk directories recursively. As far as solutions for this, this looked promising: How to use shell magic to create a recursive etags using GNU etags?
etag docs: https://www.gnu.org/software/emacs/manual/html_node/eintr/etags.html
I work on C++ projects, and I went through Alex Ott's guide to CEDET and other threads about tags in StackOverflow, but I am still confused about how Emacs interfaces with these different tag systems to facilitate autocompletion, the looking up of definitions, navigation of source code base or the previewing of doc-strings.
What is the difference (e.g. in terms of features) between etags, ebrowse, exuberant ctags, cscope, GNU Global and GTags? What do I need to do to use them in Emacs?
Do I need semantic/senator (CEDET) if I want to use tags to navigate/autocomplete symbols?
What does semantic bring to the table on top of these different tag utilities? How does it interface with these tools?
That's as a good question as I've recently read here, so I'll try explain the difference in more detail:
Point 1:
etags and ctags both generate an index (a.k.a. tag/TAGS) file of language objects found in source files that allows these items to be quickly and easily located by a text editor or other utility. A tag signifies a language object for which an index entry is available (or, alternatively, the index entry created for that object). The tags generated by ctags are richer in terms of metadata, but Emacs cannot interpret the additional data anyways, so you should consider them more or less the same (the main advantage of ctags would be its support for more languages). The primary use for the tags files is looking up class/method/function/constant/etc declaration/definitions.
cscope is much more powerful beast (at least as far as C/C++ and Java are concerned). While it operates on more or less the same principle (generating a file of useful metadata) it allows you do some fancier things like find all references to a symbol, see where a function is being invoked, etc (you can find definitions as well).
To sum it up:
ctags one allows you to navigate to symbol declaration/definitions (what some would call a one-way lookup). ctags is a general purpose tool useful for many languages.
On the other hand (as mentioned on the project's page) cscope allows you to:
Go to the declaration of a symbol
Show a selectable list of all references to a symbol
Search for any global definition
Functions called by a function
Functions calling a function
Search for a text string
Search for a regular expression pattern
Find a file
Find all files including a file
It should come as no surprise to anyone at this point, that when I deal with C/C++ projects I make heavy use of cscope and care very little about ctags. When dealing with other languages the situation would obviously be reversed.
Point 2.
To have intelligent autocompletion you need a true source code parser (like semantic), otherwise you won't know the types of the objects (for instance) in your applications and the methods that can be invoked on them. You can have an autocompletion based on many different sources, but to get the best results you'll ultimately need a parser. Same goes for syntax highlighting - currently syntax highlighting in Emacs major modes is based simply on regular expressions and that's very fragile and error prone. Hopefully with the inclusion of semantic in Emacs 23.2 (it used to be an external package before that) we'll start seeing more uses for it (like using it to analyse a buffer source code to properly highlight it)
Since Emacs 24.1 semantic is usable from the Emacs completion framework. The easiest way to test it is to open up a C source code file and typing M-TAB or C-M-i and watch as semantic automagically completes for you. For languages where semantic is not enabled by default, you can add it the following line to your major mode hook of choice:
(add-to-list 'completion-at-point-functions 'semantic-completion-at-point-function)
Point 3.
semantic brings true code awareness (for the few languages it currently supports) and closes the gap between IDEs and Emacs. It doesn't really interface with tools like etags and cscope, but it doesn't mean you cannot use them together.
Hopefully my explanations make sense and will be useful to you.
P.S. I'm not quite familiar with global and ebrowse, but if memory serves me they made use of etags.
I'll try to add some explanations to 1.
What is it?
Etags is a command to generate 'TAGS' file which is the tag file for Emacs. You can use the file with etags.el which is part of emacs package.
Ctags is a command to generate 'tags' file which is the tag file for vi. Universal Ctags, the successor of Exuberant Ctags, can generate 'TAGS' file by the -e option, supporting more than 41 programming languages.
Cscope is an all-in-one source code browsing tool for C language. It has own fine CUI (character user interface) and tag databases (cscope.in.out, cscope.out, cscope.po.out). You can use cscope from Emacs using xcscope.el which is part of cscope package.
GNU GLOBAL is a source code tagging system. Though it is similar to above tools, it differs from them at the point of that it is dependent from any editor, and it has no user interface except for command line. Gtags is a command to generate tag files for GLOBAL (GTAGS, GRTAGS, GPATH). You can use GLOBAL from emacs using gtags.el which is part of GLOBAL package. In addition to this, there are many elisp libraries for it (xgtags.el, ggtags.el, anything-gtags.el, helm-gtags.el, etc).
Comparison
Ctags and etags treat only definitions. Cscope and GNU GLOBAL treat not only definitions but also references.
Ctags and etags use a flat text tag file. Cscope and GNU GLOBAL use key-value tag databases.
Cscope and GNU GLOBAL have a grep like search engine and incremental updating facility of tag files.
Combination
You can combine Universal Ctags's rich language support and GNU GLOBAL's database facility by using ctags as a plug-in parser of GLOBAL.
Try the following: (requires GLOBAL-6.5.3+ and Universal Ctags respectively)
Building GNU GLOBAL:
$ ./configure --with-universal-ctags=/usr/local/bin/ctags
$ sudo make install
Usage:
$ export GTAGSCONF=/usr/local/share/gtags/gtags.conf
$ export GTAGSLABEL=new-ctags
$ gtags # invokes Universal Ctags internally
$ emacs -f gtags-mode # load gtags.el
(However, you cannot treat references by this method, because ctags don't treat references.)
You can also use cscope as a client of GNU GLOBAL. GLOBAL package includes a command named 'gtags-cscope' which is a port of cscope, that is, it is cscope itself except that it use GLOBAL as a search engine instead of cscope's one.
$ gtags-cscope # this is GLOBAL version of cscope
With the combinations, you can use cscope for 41 languages.
Good luck!
TAGS files contain definitions
A TAGS file contains a list of where functions and classes are defined. It is usually placed in the root of a project and looks like this:
^L
configure,3945
as_fn_success () { as_fn_return 0; }^?as_fn_success^A180,5465
as_fn_failure () { as_fn_return 1; }^?as_fn_failure^A181,5502
as_fn_ret_success () { return 0; }^?as_fn_ret_success^A182,5539
as_fn_ret_failure () { return 1; }^?as_fn_ret_failure^A183,5574
This enables Emacs to find definitions. Basic navigation is built-in with find-tag, but etags-select provides a nicer UI when there are multiple matches.
You can also uses TAGS files for code completion. For example, company's etags backend uses TAGS files.
TAGS files can be built by different tools
ctags (formerly known as 'universal ctags' or 'exuberant ctags') can generate TAGS files and supports the widest range of languages. It is actively maintained on github.
Emacs ships with two programs that generate TAGS files, called etags and ctags. Emacs' ctags is just etags with the same CLI interface as universal ctags. To avoid confusion, many distros rename these programs (e.g. ctags.emacs24 on Debian).
There are also language specific tools for generating TAGS files, such as jsctags and hasktags.
Other file formats
ebrowse is a C program shipped with Emacs. It indexes C/C++ code and generates a BROWSE file. ebrowse.el provides the usual find definition and completion. You can also open the BROWSE file directly in Emacs to get an overview of the classes/function defined a codebase.
GNU Global has its own database format, which consists of a GTAGS, GRTAGS and GPATH file. You can generate these files with the gtags command, which parses C/C++ code. For other languages, GNU Global can read files generated by universal ctags.
GNU Global also provides a CLI interface for asking more sophisticated questions, like 'where is this symbol mentioned?'. It ships with an Emacs package gtags.el, but ggtags.el is also popular for accessing GNU Global databases.
Cscope is similar in spirit to GNU Global: it parses C/C++ into its own database format. It can also answer questions like 'find all callers/callees of this funciton'.
See also this HN discussion comparing global and cscope.
Client/Server projects
rtags parses and indexes C/C++ using a persistent server. It uses the clang parser, so it handles C++ really well. It ships with an Emacs package to query the server.
google-gtags was a project where a large TAGS file would be stored on a server. When you queried the server, it would provide a subset of the TAGS file that was relevant to your search.
Semantic (CEDET)
Semantic is a built-in Emacs package that contains a parser for C/C++, so it can find definitions too. It can also import data from TAGS files, csope databases, and other sources. CEDET also includes IDE style functionality that uses this data, e.g. generating UML diagrams of class hierarchies.
[answer updated from shigio's]
I'll try to add some explanations to part 1 of the question.
What is it?
Etags generates a TAGS file which is the tag file format for Emacs. You can use an Etags file with etags.el which is part of Emacs.
Ctags is the generic term for anything that can generate a tags file, which is the native tag file format for Vi. Universal Ctags (aka UCtags, formerly Exuberant Ctags) can also generate Etags with the -e option.
Cscope is an all-in-one source code browsing tool for C (with lesser support for C++ and Java), with its own tag databases (cscope.in.out, cscope.out, cscope.po.out) and TUI. Cscope support is built-in to Vim; you can use Cscope from Emacs using the xcscope.el package. There are also Cscope-based GUIs.
GNU GLOBAL (aka Gtags) is yet another source code tagging system (with significant differences--see next section), in that it also generates tag files.
Comparison
Ctags and Etags treat only definitions (of, e.g., variables and functions). Cscope and Gtags also treat references.
Ctags and Etags tag files are flat. Cscope and Gtags tagfiles are more powerful key-value databases, which allows (e.g.) incremental update.
Cscope and Gtags have a grep-like search engine.
Ctags has built-in support for more languages and data formats: see the current-in-repository list of Universal Ctags parsers. UCtags also has documented how to develop your own parser.
Cscope and Gtags are editor-independent.
Gtags does not provide its own user interface, but can currently (Oct 2016) be used from commandline (CLI), Emacs and relatives, Vi and relatives, less (pager), Doxygen, and any web browser.
Gtags provides gtags.el via the GLOBAL package, but there are also many other elisp extensions, including xgtags.el, ggtags.el, anything-gtags.el, helm-gtags.el.
Combination
You can combine Universal Ctags' rich language support with Gtags' database facility and numerous extensions by using Ctags as a GLOBAL plug-in parser:
# build GNU GLOBAL
./configure --with-exuberant-ctags=/usr/local/bin/ctags
sudo make install
# use it
export GTAGSCONF=/usr/local/share/gtags/gtags.conf
export GTAGSLABEL=ctags
gtags # invokes Universal Ctags internally
emacs -f gtags-mode # load gtags.el
Note again that if you use Ctags as the parser for your Gtags, you lose the ability to treat references (e.g., variable usage, function calls) which Gtags would otherwise provide. Essentially, you trade off Gtags' reference tracking for Ctags' greater built-in language support.
You can also use Cscope as a client of Gtags: gtags-cscope.
Good luck!
I haven't actually checked, but according to CEDET manual (http://www.randomsample.de/cedetdocs/common/cedet/CScope.html):
semantic can use CScope as a back end for database searches. To enable it, use:
(semanticdb-enable-cscope-databases)
This will enable the use of cscope for all C and C++ buffers.
CScope will then be used for project-wide searches as a backup when pre-existing semantic database searches may not have parsed all your files.
I am switching to Emacs from TextMate. One feature of TextMate that I would really like to have in Emacs is the "Find in Project" search box that uses fuzzy matching. Emacs sort of has this with ido, but ido does not search recursively through child directories. It searches only within one directory.
Is there a way to give ido a root directory and to search everything under it?
Update:
The questions below pertain to find-file-in-project.el from Michał Marczyk's answer.
If anything in this message sounds obvious it's because I have used Emacs for less than one week. :-)
As I understand it, project-local-variables lets me define things in a .emacs-project file that I keep in my project root.
How do I point find-file-in-project to my project root?
I am not familiar with regex syntax in Emacs Lisp. The default value for ffip-regexp is:
".*\\.\\(rb\\|js\\|css\\|yml\\|yaml\\|rhtml\\|erb\\|html\\|el\\)"
I presume that I can just switch the extensions to the ones appropriate for my project.
Could you explain the ffip-find-options? From the file:
(defvar ffip-find-options
""
"Extra options to pass to `find' when using find-file-in-project.
Use this to exclude portions of your project: \"-not -regex \\".vendor.\\"\"")
What does this mean exactly and how do I use it to exclude files/directories?
Could you share an example .emacs-project file?
I use M-x rgrep for this. It automatically skips a lot of things you don't want, like .svn directories.
(Updated primarily in order to include actual setup instructions for use with the below mentioned find-file-in-project.el from the RINARI distribution. Original answer left intact; the new bits come after the second horizontal rule.)
Have a look at the TextMate page of the EmacsWiki. The most promising thing they mention is probably this Emacs Lisp script, which provides recursive search under a "project directory" guided by some variables. That file begins with an extensive comments section describing how to use it.
What makes it particularly promising is the following bit:
;; If `ido-mode' is enabled, the menu will use `ido-completing-read'
;; instead of `completing-read'.
Note I haven't used it myself... Though I may very well give it a try now that I've found it! :-)
HTH.
(BTW, that script is part of -- to quote the description from GitHub -- "Rinari Is Not A Rails IDE (it is an Emacs minor mode for Rails)". If you're doing any Rails development, you might want to check out the whole thing.)
Before proceeding any further, configure ido.el. Seriously, it's a must-have on its own and it will improve your experience with find-file-in-project. See this screencast by Stuart Halloway (which I've already mentioned in a comment on this answer) to learn why you need to use it. Also, Stu demonstrates how flexible ido is by emulating TextMate's project-scoped file-finding facility in his own way; if his function suits your needs, read no further.
Ok, so here's how to set up RINARI's find-file-in-project.el:
Obtain find-file-in-project.el and project-local-variables.el from the RINARI distribution and put someplace where Emacs can find them (which means in one of the directories in the load-path variable; you can use (add-to-list 'load-path "/path/to/some/directory") to add new directories to it).
Add (require 'find-file-in-project) to your .emacs file. Also add the following to have the C-x C-M-f sequence bring up the find-file-in-project prompt: (global-set-key (kbd "C-x C-M-f") 'find-file-in-project).
Create a file called .emacs-project in your projects root directory. At a minimum it should contain something like this: (setl ffip-regexp ".*\\.\\(clj\\|py\\)$"). This will make it so that only files whose names and in clj or py will be searched for; please adjust the regex to match your needs. (Note that this regular expression will be passed to the Unix find utility and should use find's preferred regular expression syntax. You still have to double every backslash in regexes as is usual in Emacs; whether you also have to put backslashes before parens / pipes (|) if you want to use their 'magic' regex meaning depends on your find's expectations. The example given above works for me on an Ubuntu box. Look up additional info on regexes in case of doubt.) (Note: this paragraph has been revised in the last edit to fix some confusion w.r.t. regular expression syntax.)
C-x C-M-f away.
There's a number of possible customisations; in particular, you can use (setl ffip-find-options "...") to pass additional options to the Unix find command, which is what find-file-in-project.el calls out to under the hood.
If things appear not to work, please check and double check your spelling -- I did something like (setl ffip-regex ...) once (note the lack of the final 'p' in the variable name) and were initially quite puzzled to discover that no files were being found.
Surprised nobody mentioned https://github.com/defunkt/textmate.el (now gotta make it work on Windows...)
eproject has eproject-grep, which does exactly what you want.
With the right project definition, it will only search project files; it will ignore version control, build artifacts, generated files, whatever. The only downside is that it requires a grep command on your system; this dependency will be eliminated soon.
You can get the effect you want by using GNU Global or IDUtils. They are not Emacs specific, but they has Emacs scripts that integrate that effect. (I don't know too much about them myself.)
You could also opt to use CEDET and the EDE project system. EDE is probably a bit heavy weight, but it has a way to just mark the top of a project. If you also keep GNU Global or IDUtils index files with your project, EDE can use it to find a file by name anywhere, or you can use `semantic-symref' to find references to symbols in your source files. CEDET is at http://cedet.sf.net
For pure, unadulterated speed, I highly recommend a combination of the command-line tool The Silver Searcher (a.k.a. 'ag') with ag.el. The ag-project interactive function will make an educated guess of your project root if you are using git, hg or svn and search the entire project.
FileCache may also be an option. However you would need to add your project directory manually with file-cache-add-directory-recursively.
See these links for info about how Icicles can help here:
find files anywhere, matching any parts of their name (including directory parts)
projects: create, organize, manage, search them
Icicles completion matching can be substring, regexp, fuzzy (various kinds), or combinations of these. You can also combine simple patterns, intersecting the matches or complementing (subtracting) a subset of them