Re: From etags to ctags?

[John Yates]

On Wed, Jun 4, 2014 at 3:40 PM, Stefan Monnier <address@hidden> wrote:

> For instance Edward Bishop's vtags fork?

I know nothing about it.  If we can get its copyright cleared, then it'd
probably be a good starting point (we'd probably want to try and
integrate it more with the current tags functionality).

My reason for using vtags has never been the additional annotations.  They just turned out to be an unexpected extra.  The important thing about vtags is that it assumes a binary searchable external tags file and offers other UI improvements.  Definitely a source of idea.

/john

;; Added tags (as opposed to TAGS) functionality.

;; The code now has the ability to parse vi-style

;; tags tables generated by Exuberant Ctags.

;; By introduction of vtags-get-tagfile-header and struct tagfileinfo, we have tried

;; to make the higher-level functions tag-type agnostic and non-buffer-centric. 

;; Many functions that used to assume that the TAGS file is in

;; the current buffer now take a tagfileinfo, or tfi, parameter. 

;;

;; Changed the behavior of vtags-find for multiple matches. Previously the user

;; could iterate through the matches one at a time. Now the user

;; is presented with all the matches at once in a buffer, similar 

;; to the way that completions, list-tags, or tags-apropos are handled.

;; Removed next-p in vtags-find-internal, etc. Now vtags-find-internal searches all tag files.

;;

;; Deprecated the tag ring in favor of placeholders.

;; Placeholders navigation is more natural, allowing forward and back, 

;; similar to the way debuggers allow programmers to navigate up and down 

;; a call stack, or to the way browsers allow history navigation.

;;

;; Ripped out cached completions, i.e. tags-completion-table.

;; These are not useful since they take forever to compute without a prefix

;; (and people almost never use completion without a prefix).

;;

;; Eliminated tags-file-name. Users should use vtags-table-list instead.

;; There were too many global variables tracking

;; the same or overlapping functionality.

;;

;; Eliminated select-tags-table and all other references to tags-table-set-list.

;; There may be some merit to allowing the user to select a set of tags tables

;; from a list of sets, but it seems to me that the previous implementation

;; was too complicated, too rigid, and too poorly documented, and too implicitly

;; entangled with the rest of the tags functionality to be easily salvageable.

;; See Design Notes below.

;;

;; Eliminated `tags-table-computed-list'. There is no evidence that

;; this optimization was needed.  Let Emacs and the OS cache file stats

;; if needed.

;; 

;; Removed 'button and 'apropos dependency, using vtags-mode instead.

;; We don't need all the features of button and apropos, and removing

;; them makes the code more portable and independent.