The critical weakness of this option is that this option does not print the name of kind. Universal Ctags introduces --list-kinds-full because it considers that names are important. This option does not work with --machinable nor --with-list-header. Each kind of tag recorded in the tag file is represented by a one-letter flag, or a long-name flag.
The master parser controlling enablement of the kind. In other words, the namespace of kinds are separated by language. To emulate this behavior in Universal Ctags, a concept named master parser is introduced. If you swap the languages, you see the same result. Lists the names of the languages understood by ctags, and then exits. Each language listed is disabled if followed by [disabled]. To list the file extensions or file name patterns individually, use --list-map-extensions or --list-map-patterns option.
Prints statistics about the source files read and the tag file written during the current invocation of ctags. This option is no by default. The extra value prints parser specific statistics for parsers gathering such information.
If a language was identified, the file is opened and then the appropriate language parser is called to operate on the currently open file. The parser parses through the file and adds an entry to the tag file for each language object it is written to handle. This implementation of ctags imposes no formatting requirements on C code as do legacy implementations. Older implementations of ctags tended to rely upon certain formatting assumptions in order to help it resolve coding dilemmas caused by preprocessor conditionals.
In general, ctags tries to be smart about conditional preprocessor directives. If a preprocessor conditional is encountered within a statement which defines a tag, ctags follows only the first branch of that conditional except in the special case of if 0 , in which case it follows only the last branch.
The reason for this is that failing to pursue only one branch can result in ambiguous syntax, as in the following example:. Both branches cannot be followed, or braces become unbalanced and ctags would be unable to make sense of the syntax. After creating or appending to the tag file, it is sorted by the tag name, removing identical tag lines. Unless the --language-force option is specified, the language of each source file is automatically selected based upon a mapping of file names to languages.
If the name of a file is not mapped to a language, ctags tries to heuristically guess the language for the file by inspecting its content. All files that have no file name mapping and no guessed parser are ignored. This permits running ctags on all files in either a single directory e. An extension may be mapped to multiple parsers.
For example,. These mappings can cause issues. Some of the heuristics are applied whether --guess-language-eagerly is given or not. If ctags cannot select a parser from the mapping of file names, various heuristic tests are conducted to determine the language:.
The first line of the file is checked to see if the file is a! If ctags finds no such parser, ctags looks for the name in alias lists.
For example, consider if the first line is! An exception is env. To display the list of aliases, use --list-aliases option. The Emacs editor has multiple editing modes specialized for programming languages. Emacs can recognize a marker called modeline in a file and utilize the marker for the mode selection. This heuristic test does the same as what Emacs does. Emacs editor recognizes another marker at the end of file as a mode specifier. Like the modeline of the Emacs editor, Vim editor has the same concept.
Looking into the file contents is a more expensive operation than file name matching. So ctags runs the testings in limited conditions. The other heuristic tests are enabled only when -G option is given. The --print-language option can be used just to print the results of parser selections for given files instead of generating a tags file. NONE means that ctags does not select any parser for the file.
This section describes the tag file format briefly. See tags 5 and ctags-client-tools 7 for more details. When not running in etags mode, each entry in the tag file consists of a separate line, each looking like this, called regular tags , in the most general case:.
Tag file format 2 see --format extends the EX command to include the extension fields embedded in an EX comment immediately appended to the EX command, which leaves it backward-compatible with original vi 1 implementations. A few special tags, called pseudo tags , are written into the tag file for internal purposes. See also tags 5 and ctags-client-tools 7 for more details of the pseudo tags. These tags are composed in such a way that they always sort to the top of the file.
Therefore, the first two characters of these tags are used a magic number to detect a tag file for purposes of determining whether a valid tag file is being overwritten rather than a source file.
Note that the name of each source file will be recorded in the tag file exactly as it appears on the command line. Therefore, if the path you specified on the command line was relative to the current directory, then it will be recorded in that same manner in the tag file.
A tag is an index for a language object. The concept of a tag and related items in Exuberant Ctags are refined and extended in Universal Ctags. A tag is categorized into definition tags or reference tags. In general, Exuberant Ctags only tags definitions of language objects: places where newly named language objects are introduced.
Universal Ctags, on the other hand, can also tag references of language objects: places where named language objects are used.
However, support for generating reference tags is new and limited to specific areas of specific languages in the current version. Extension fields are tab-separated key-value pairs appended to the end of the EX command as a comment, as described above. These key value pairs appear in the general form key:value. In addition, information on the scope of the tag definition may be available, with the key portion equal to some language-dependent construct name and its value the name declared for that construct in the program.
This scope entry indicates the scope in which the tag was found. For example, a tag generated for a C structure member would have a scope looking like struct:myStruct. The essential fields are name , input , pattern , and line. Kinds used and defined are very different between parsers. For example, C language defines macro , function , variable , typedef , etc. Its value is either one of the corresponding one-letter flags or a long-name flag. It is permitted and is, in fact, the default for the key portion of this field to be omitted.
The optional behaviors are controlled with the --fields option as follows. Role is a newly introduced concept in Universal Ctags. Role is a concept associated with reference tags, and is not implemented widely yet. For such reference kinds, a roles field can be added to distinguish the role of the reference kind.
In other words, the kind field identifies the what of the language object, whereas the roles field identifies the how of a referenced language object. Roles are only used with specific kinds. For a definition tag, this field takes def as a value. For example, Baz is tagged as a reference tag with kind package and with role imported with the following code. Generally, ctags tags only language objects appearing in source files, as is.
In other words, a value for a name: field should be found on the source file associated with the name:. An extra type tag extra is for tagging a language object with a processed name, or for tagging something not associated with a language object. A typical extra tag is qualified , which tags a language object with a class-qualified or scope-qualified name.
Inquire the output of ctags --list-extras for the list of extras. Include an entry for the language object that has no name like lambda function. This extra has no one-letter flag and is enabled by default. The extra tag is useful as a placeholder to fill scope fields for language objects defined in a language object with no name. For overcoming the trouble, ctags generates an anonymous extra tag for the struct and fills the scope fields with the name of the extra tag.
Indicates whether tags scoped only for a single file i. However, in 6. About C language, this looks good idea for me if I can ignore the existing kinds in C parser. C parser already defines parameter kind and local kind. We can extend the field to support the scope classes, global, file, local, and parameter. I have to think about this idea more. As the name implies, ctags might be designed for C language originally.
Skip to content. Star 4. New issue. Jump to bottom. Labels Documentation Incompatibilities Main part. Milestone M2 for 6. Copy link. Regards, Gur The text was updated successfully, but these errors were encountered:. Thank you for reporting this. I didn't test parameter ordering issues. Does the following produce the same results? Providing the two way to control the same thing in Universal-ctags internal can cause a trouble.
Some pros and cons I can think of from the top of my head: Incompatibility might push users away higher entry barrier, feeling that Universal-CTags is buggy, etc.
Incompatibility allows to fix some existing issues consistency issues, usability issues, etc. Incompatibility with a de facto open standard fights competition and innovation unless the de-facto standard is itself blocking innovation In the end, I would think it boils down to 2 things: how important is compatibility, and how problematic it is.
As the result of 3 years efforts, the options are simplified as follows: kinds related options, fields related options, extras related options, roles related options, and params related options. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow.
Learn more. Asked 9 years, 11 months ago. Active 9 years, 11 months ago. Viewed 4k times. The second way: Use nm command, like: nm builtsource. Improve this question. Twd Twd 41 1 1 silver badge 3 3 bronze badges. However sedding for 'const' won't get you anywhere near ignoring const global, it can be a non-const pointer to const or even a name like 'constant'.
Sure, I agree about sedding regular expression, it was a sort of naive solution. Eclipse CDT has a decent parser but it isn't designed to work standalone for reasons which elude me. Collectives on Stack Overflow.
Learn more. Asked 9 years, 3 months ago. Active 1 year, 4 months ago. Viewed 25k times. Improve this question.
Wilfred Hughes Judging by the trunk , the GTags project you linked to is quite dead. If someone's talking about gtags , they're probably referring to GNU Global.
Add Universal Ctags -- the maintained fork of Exuberant Ctags -- to the mix : ggtags is the Emacs package for this. Add a comment. Active Oldest Votes. 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. Point 2. 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.
Hopefully my explanations make sense and will be useful to you. Improve this answer. Bozhidar Batsov Bozhidar Batsov This is great. Do you know how can I use cscope in Emacs?
I read about xcscope. Also, which. That's what I use. One more question: How does semantic compare with cscope? In terms of navigating through the source code, does semantic provide any functionality that cscope doesn't? Do you use both? I don't believe GNU Global use etags, btw. IIRC it maintains and queries a 'proper' database rather than scanning a flat text file , which has numerous performance benefits both for querying and especially for updating the tags.
BozhidarBatsov When you said For languages where semantic is not enabled by default, you can add the following line to your major mode hook of choice What does that code snippet exactly do? Show 1 more comment.
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