UCTAGS(7)

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

SYNOPSIS
uctags [options] [file(s)]
uetags [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".

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).