CTAGS(7)

NAME
ctags - Incompatibilities between Universal-ctags and Exuberant-ctags

SYNOPSIS
ctags [options] [file(s)]
etags [options] [file(s)]

DESCRIPTION

This page describes major incompatible changes introduced to Universal-ctags forked from Exuberant-ctags.

INCOMPATIBILITIES IN COMMAND LINE INTERFACE

  The order of application of patterns and extensions in --langmap

When applying mappings for a name of given source file, Exuberant-ctags tests file name patterns AFTER file extensions (e-map-order). Universal-ctags does this differently; it tests file name patterns BEFORE file extensions (u-map-order).

This incompatible change is introduced to deal with the following situation:

•   "build.xml" as a source file,

•   The "Ant" parser declares it handles a file name pattern "build.xml", and

•   The "XML" parser declares it handles a file extension "xml".

    Which parser should be used for parsing "build.xml"? The assumption of Universal-ctags is the user may want to use the "Ant" parser; the file name pattern it declares is more specific than the file extension that the "XML" parser declares. However, e-map-order chooses the "XML" parser.

    So Universal-ctags uses the u-map-order even though it introduces an incompatibility.

    --list-map-extensions=language and --list-map-patterns=language options are helpful to verify and the file extensions and the file name patterns of given language.

  Unexpected synchronization between --file-scope option and F/fileScope extra

Universal-ctags introduces "F/fileScope" extra as the alternative to --file-scope option.

Providing the two way to control the same thing in Universal-ctags internal can cause a trouble.

A user, expecting "--file-scope=yes" is enabled by default, gives "--extras=q". The intention of the user may be just enabling "q/qualified". However, "--extras=q" is evaluated as "disabling all extras including F/fileScope, then enabling only q/qualified". Unexpectedly the command line becomes as if "--file-scope=no" is set.

In this case, the user should set "--extras=+q" instead of "--extras=q".

  Obsoleting --<LANG>-kinds option

Some options have <LANG> as parameterized parts in their name like --foo-<LANG>=... or --<LANG>-foo=.... The most of all such options in Exuberant-ctags have the former form, --foo-<LANG>=.... The exception is --<LANG>-kinds.

Universal-ctags uses the former form for all <LANG> parameterized option. Use --kinds-<LANG> instead of --<LANG>-kinds in Universal-ctags. --<LANG>-kinds still works but it will be removed in the future.

The former form may be friendly to shell completion engines.

  Disallowing to define a kind with file as name

The kind name "file" is reserved. Using it as part of kind spec in --regex-<LANG> option is now disallowed.

INCOMPATIBILITIES IN TAGS FILE FORMAT

OPTION FILES LOADING AT STARTING UP TIME (PRELOAD FILES)

File paths for preload files are changed. Universal-ctags doesn't load "~/.ctags" at starting up time. See "FILES" section of ctags(1).

KIND LETTERS AND NAMES

A kind letter "F" and a kind name "file" are reserved in the main part. A parser cannot have a kind conflicting with these reserved ones. Some incompatible changes are introduced to follow the above rule.

•   Cobol's "file" kind is renamed to "fileDesc" because the kind name "file" is reserved.

•   Ruby's "F" (singletonMethod) is changed to "S".

•   SQL's "F" (field) is changed to "E".