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diff --git a/doc/easytags.txt b/doc/easytags.txt new file mode 100644 index 0000000..4523cca --- /dev/null +++ b/doc/easytags.txt @@ -0,0 +1,374 @@ +*easytags.txt* Automated tag generation and syntax highlighting in Vim + +Vim has long been my favorite text editor and combined with Exuberant Ctags +[1] it has the potential to provide most of what I expect from an integrated +development environment [2]. Exuberant Ctags is the latest incarnation of a +family of computer programs [3] that scan source code files to create an index +of identifiers (tags) and where they are defined. Vim uses this index (a +so-called tags file) to enable you to jump to the definition of any identifier +using the Control-] (see |CTRL-]|) mapping. + +When you're familiar with integrated development environments you may +recognize this feature as "Go-to definition". One advantage of the combination +of Vim and Exuberant Ctags over integrated development environments is that +Vim supports syntax highlighting for over 500 file types [4] (!) and Exuberant +Ctags can generate tags for over 40 file types [5] as well... + +There's just one problem: You have to manually keep your tags files up-to-date +and this turns out to be a royal pain in the ass! So I set out to write a Vim +plug-in that would do this boring work for me. When I finished the plug-in's +basic functionality (one automatic command and a call to |system()| later) I +became interested in dynamic syntax highlighting, so I added that as well to +see if it would work -- surprisingly well I'm happy to report! + +============================================================================== +Install & usage ~ + +Unzip the most recent ZIP archive [6] file inside your Vim profile directory +(usually this is '~/.vim' on UNIX and '%USERPROFILE%\vimfiles' on Windows), +restart Vim and execute the command ':helptags ~/.vim/doc' (use ':helptags +~\vimfiles\doc' instead on Windows). Now try it out: Edit any file type +supported by Exuberant Ctags and within ten seconds the plug-in should +create/update your tags file ('~/.vimtags' on UNIX, '~/_vimtags' on Windows) +with the tags defined in the file you just edited! This means that whatever +file you're editing in Vim (as long as it's on the local file system), tags +will always be available by the time you need them! + +Additionally if the file you just opened is a C, C++, Objective-C, Java, Lua, +Python, PHP or Vim source file you should also notice that the function and +type names defined in the file have been syntax highlighted. + +The 'easytags.vim' plug-in is intended to work automatically once it's +installed, but if you want to change how it works there are several options +you can change and commands you can execute from your own mappings and/or +automatic commands. These are all documented below. + +Note that if the plug-in warns you 'ctags' isn't installed you'll have to +download it from its homepage [1], or if you're running Debian/Ubuntu you can +install it by executing the following shell command: +> + $ sudo apt-get install exuberant-ctags + +------------------------------------------------------------------------------ +If you're using Windows ~ + +On Windows the |system()| function used by 'easytags.vim' causes a command +prompt window to pop up while Exuberant Ctags is executing. If this bothers +you then you can install my shell.vim [7] plug-in which includes a DLL [8] +that works around this issue. Once you've installed both plug-ins it should +work out of the box! Please let me know if this doesn't work for you. + +------------------------------------------------------------------------------ +The *:UpdateTags* command + +This command executes Exuberant Ctags [1] from inside Vim to update the global +tags file defined by |g:easytags_file|. When no arguments are given the tags for +the current file are updated, otherwise the arguments are passed on to +'ctags'. For example when you execute the Vim command ':UpdateTags -R ~/.vim' +(or ':UpdateTags -R ~\vimfiles' on Windows) the plug-in will execute 'ctags -R +~/.vim' for you (with some additional arguments, see the troubleshooting +section ":HighlightTags only works for the tags file created by |:UpdateTags|" +for more information). + +When you execute this command like |:UpdateTags|! (including the bang!) then all +tags whose files are missing will be filtered from the global tags file. + +Note that this command will be executed automatically every once in a while, +assuming you haven't changed |g:easytags_on_cursorhold|. + +------------------------------------------------------------------------------ +The *:HighlightTags* command + +When you execute this command while editing one of the supported file types +(see above) the relevant tags in the current file are highlighted. The tags to +highlight are gathered from all tags files known to Vim (through the |'tags'| +option). + +Note that this command will be executed automatically every once in a while, +assuming you haven't changed |g:easytags_on_cursorhold|. + +------------------------------------------------------------------------------ +The *g:easytags_cmd* option + +The plug-in will try to determine the location where Exuberant Ctags is +installed on its own but this might not always work because any given +executable named 'ctags' in your '$PATH' might not in fact be Exuberant Ctags +but some older, more primitive 'ctags' implementation which doesn't support +the same command line options and thus breaks the 'easytags.vim' plug-in. If +this is the case you can set the global variable |g:easytags_cmd| to the +location where you've installed Exuberant Ctags, e.g.: +> + :let g:easytags_cmd = '/usr/local/bin/ctags' + +------------------------------------------------------------------------------ +The *g:easytags_file* option + +As mentioned above the plug-in will store your tags in '~/.vimtags' on UNIX +and '~/_vimtags' on Windows. To change the location of this file, set the +global variable |g:easytags_file|, e.g.: +> + :let g:easytags_file = '~/.vim/tags' + +A leading '~' in the |g:easytags_file| variable is expanded to your current home +directory ('$HOME' on UNIX, '%USERPROFILE%' on Windows). + +------------------------------------------------------------------------------ +The *g:easytags_always_enabled* option + +By default the plug-in automatically generates and highlights tags when you +stop typing for a few seconds (this works using the |CursorHold| automatic +command). This means that when you edit a file, the dynamic highlighting won't +appear until you pause for a moment. If you don't like this you can configure +the plug-in to always enable dynamic highlighting: +> + :let g:easytags_always_enabled = 1 + +Be warned that after setting this option you'll probably notice why it's +disabled by default: Every time you edit a file in Vim, the plug-in will first +run Exuberant Ctags and then highlight the tags, and this slows Vim down quite +a lot. I have some ideas on how to improve this latency by running Exuberant +Ctags in the background so stay tuned! + +Note: If you change this option it won't apply until you restart Vim, so +you'll have to set this option in your |vimrc| script. + +------------------------------------------------------------------------------ +The *g:easytags_on_cursorhold* option + +As I explained above the plug-in by default doesn't update or highlight your +tags until you stop typing for a moment. The plug-in tries hard to do the +least amount of work possible in this break but it might still interrupt your +workflow. If it does you can disable the periodic update: +> + :let g:easytags_on_cursorhold = 0 + +Note: Like the |g:easytags_always_enabled| option, if you change this option it +won't apply until you restart Vim, so you'll have to set this option in your +|vimrc| script. + +------------------------------------------------------------------------------ +The *g:easytags_autorecurse* option + +When the |:UpdateTags| command is executed automatically or without arguments, +it defaults to updating just the tags for the current file. If you'd rather +have it recursively scan everything below the directory of the current file +then set this option to true (1): +> + :let g:easytags_autorecurse = 1 + +You have to explicitly enable this option because it should only be used while +navigating around small directory trees. Imagine always having this option +enabled and then having to edit a file in e.g. the root of your home +directory: The 'easytags.vim' plug-in would freeze Vim for a long time while +you'd have to wait for Exuberant Cags to scan thousands of files... + +Note that when you enable this option the 'easytags.vim' plug-in might ignore +other options like |g:easytags_resolve_links|. This is an implementation detail +which I intend to fix. + +------------------------------------------------------------------------------ +The *g:easytags_include_members* option + +Exuberant Ctags knows how to generate tags for struct/class members in C++ and +Java source code but doesn't do so by default because it can more than double +the size of your tags files, thus taking much longer to read/write the tags +file. When you enable the |g:easytags_include_members| option from your |vimrc| +script (before the 'easytags.vim' plug-in is loaded): +> + :let g:easytags_include_members = 1 + +Exuberant Ctags will be instructed to include struct/class members using the +'--extra=+q' command line argument and the 'easytags.vim' plug-in will +highlight them using the 'cMember' highlighting group. Because most color +schemes don't distinguish the Identifier and Type (see |group-name|) +highlighting groups all members will now probably look like type definitions. +You can change that by executing either of the following Vim commands (from +your vimrc script, a file type plug-in, etc.): +> + " If you like one of the existing styles you can link them: + highlight link cMember Special +> + " You can also define your own style if you want: + highlight cMember gui=italic + +------------------------------------------------------------------------------ +The *g:easytags_resolve_links* option + +UNIX has symbolic links [9] and hard links [10], both of which conflict with +the concept of having one unique location for every identifier. With regards +to hard links there's not much anyone can do, but because I use symbolic links +quite a lot I've added this option. It's disabled by default since it has a +small performance impact and might not do what unknowing users expect it to: +When you enable this option the plug-in will resolve symbolic links in +pathnames, which means your tags file will only contain entries with canonical +pathnames [11]. To enable this option (which I strongly suggest doing when you +run UNIX and use symbolic links) execute the following Vim command: +> + :let g:easytags_resolve_links = 1 + +------------------------------------------------------------------------------ +The *g:easytags_suppress_ctags_warning* option + +If this is set and not false, it will suppress the warning on startup if ctags +is not found or not recent enough. +> + :let g:easytags_suppress_ctags_warning = 1 + +------------------------------------------------------------------------------ +How to customize the highlighting colors? ~ + +The easytags plug-in defines new highlighting groups for dynamically +highlighted tags. These groups are linked to Vim's default groups so that +they're colored out of the box, but if you want you can change the styles. To +do so use a 'highlight' command such as the ones given a few paragraphs back. +Of course you'll need to change the group name. Here are the group names used +by the easytags plug-in: + + * Lua: 'luaFuncTag' + * C: 'cTypeTag', 'cEnumTag', 'cPreProcTag', 'cFunctionTag', 'cMemberTag' + * PHP: 'phpFunctionsTag', 'phpClassesTag' + * Vim: 'vimAutoGroupTag', 'vimCommandTag', 'vimFuncNameTag', + 'vimScriptFuncNameTag' + * Python: 'pythonFunctionTag', 'pythonMethodTag', 'pythonClassTag' + * Java: 'javaClassTag', 'javaMethodTag' + * C#: 'csClassOrStructTag', 'csMethodTag' + +As you can see each of these names ends in 'Tag' to avoid conflicts with the +syntax modes shipped with Vim. And about the singular/plural confusion: I've +tried to match the existing highlighting groups defined by popular syntax +modes (except of course for the 'Tag' suffix). + +============================================================================== +Troubleshooting ~ + +------------------------------------------------------------------------------ +:HighlightTags only works for the tags file created by :UpdateTags ~ + +If you want to create tags files and have their tags highlighted by the +'easytags.vim' plug-in then you'll have to create the tags file with certain +arguments to Exuberant Ctags: +> + $ ctags --fields=+l --c-kinds=+p --c++-kinds=+p ... + +The '--fields=+l' argument makes sure that Exuberant Ctags includes a +'language:...' property with each entry in the tags file. This is required by +the |:HighlightTags| command so it can filter tags by their file type. The other +two arguments make sure Exuberant Ctags generates tags for function prototypes +in C/C++ source code. + +If you have the |g:easytags_include_members| option enabled (its off by default) +then you'll also need to add the '--extra=+q' argument so that Exuberant Ctags +generates tags for structure/class members. + +------------------------------------------------------------------------------ +The plug-in complains that Exuberant Ctags isn't installed ~ + +After a Mac OS X user found out the hard way that the 'ctags' executable isn't +always Exuberant Ctags and we spend a few hours debugging the problem I added +proper version detection: The plug-in executes 'ctags --version' when Vim is +started to verify that Exuberant Ctags 5.5 or newer is installed. If it isn't +Vim will show the following message on startup: +> + easytags.vim: Plug-in not loaded because Exuberant Ctags isn't installed! + Please download & install Exuberant Ctags from http://ctags.sf.net + +If the installed Exuberant Ctags version is too old the plug-in will complain: +> + easytags.vim: Plug-in not loaded because Exuberant Ctags 5.5 + or newer is required while you have version %s installed! + +If you have the right version of Exuberant Ctags installed but the plug-in +still complains, try executing the following command from inside Vim: +> + :!which ctags + +If this doesn't print the location where you installed Exuberant Ctags it +means your system already had a 'ctags' executable but it isn't compatible +with Exuberant Ctags 5.5 and you'll need to set the |g:easytags_cmd| option (see +above) so the plug-in knows which 'ctags' to run. + +------------------------------------------------------------------------------ +Vim locks up while the plug-in is running ~ + +Once or twice now in several years I've experienced Exuberant Ctags getting +into an infinite loop when given garbage input. In my case this happened by +accident a few days ago :-|. Because my plug-in executes 'ctags' in the +foreground this will block Vim indefinitely! If this happens you might be able +to kill 'ctags' by pressing Control-C (see |CTRL-C|) but if that doesn't work +you can also kill it without stopping Vim using a task manager or the 'pkill' +command (available on most UNIX systems): +> + $ pkill -KILL ctags + +If Vim seems very slow and you suspect this plug-in might be the one to blame, +increase Vim's verbosity level: +> + :set vbs=1 + +Every time the plug-in executes it will time how long the execution takes and +add the results to Vim's message history, which you can view by executing the +|:messages| command. + +------------------------------------------------------------------------------ +Failed to highlight tags because pattern is too big! ~ + +If the 'easytags.vim' plug-in fails to highlight your tags and the error +message mentions that the pattern is too big, your tags file has grown too +large for Vim to be able to highlight all tagged identifiers! I've had this +happen to me with 50 KB patterns because I added most of the headers in +'/usr/include/' to my tags file. Internally Vim raises the error |E339|: Pattern +too long and unfortunately the only way to avoid this problem once it occurs +is to reduce the number of tagged identifiers... + +In my case the solution was to move most of the tags from '/usr/include/' over +to project specific tags files which are automatically loaded by Vim when I +edit files in different projects because I've set the |'tags'| option as +follows: +> + :set tags=./.tags;,~/.vimtags + +Once you've executed the above command, Vim will automatically look for a file +named '.tags' in the directory of the current file. Because of the ';' Vim +also recurses upwards so that you can nest files arbitrarily deep under your +project directories. + +------------------------------------------------------------------------------ +The plug-in doesn't seem to work in Cygwin [12] ~ + +If you want to use the plug-in with Vim under Cygwin, you need to have the +Cygwin version of Ctags installed instead of the Windows version (thanks to +Alex Zuroff for reporting this!). + +============================================================================== +Contact ~ + +If you have questions, bug reports, suggestions, etc. the author can be +contacted at peter@peterodding.com. The latest version is available at +http://peterodding.com/code/vim/easytags/ and http://github.com/xolox/vim-easytags. +If you like this plug-in please vote for it on Vim Online [13]. + +============================================================================== +License ~ + +This software is licensed under the MIT license [14]. +Copyright 2010 Peter Odding <peter@peterodding.com>. + +============================================================================== +References ~ + +[1] http://ctags.sourceforge.net/ +[2] http://en.wikipedia.org/wiki/Integrated_development_environment +[3] http://en.wikipedia.org/wiki/Ctags +[4] http://ftp.vim.org/vim/runtime/syntax/ +[5] http://ctags.sourceforge.net/languages.html +[6] http://peterodding.com/code/vim/downloads/easytags +[7] http://peterodding.com/code/vim/shell/ +[8] http://en.wikipedia.org/wiki/Dynamic-link_library +[9] http://en.wikipedia.org/wiki/Symbolic_link +[10] http://en.wikipedia.org/wiki/Hard_link +[11] http://en.wikipedia.org/wiki/Canonicalization +[12] http://en.wikipedia.org/wiki/Cygwin +[13] http://www.vim.org/scripts/script.php?script_id=3114 +[14] http://en.wikipedia.org/wiki/MIT_License + +vim: syntax=help nospell
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