view etc/ETAGS.EBNF @ 5043:d0c14ea98592

various frame-geometry fixes -------------------- ChangeLog entries follow: -------------------- src/ChangeLog addition: 2010-02-15 Ben Wing <ben@xemacs.org> * EmacsFrame.c: * EmacsFrame.c (EmacsFrameResize): * console-msw-impl.h: * console-msw-impl.h (struct mswindows_frame): * console-msw-impl.h (FRAME_MSWINDOWS_TARGET_RECT): * device-tty.c: * device-tty.c (tty_asynch_device_change): * event-msw.c: * event-msw.c (mswindows_wnd_proc): * faces.c (Fface_list): * faces.h: * frame-gtk.c: * frame-gtk.c (gtk_set_initial_frame_size): * frame-gtk.c (gtk_set_frame_size): * frame-msw.c: * frame-msw.c (mswindows_init_frame_1): * frame-msw.c (mswindows_set_frame_size): * frame-msw.c (mswindows_size_frame_internal): * frame-msw.c (msprinter_init_frame_3): * frame.c: * frame.c (enum): * frame.c (Fmake_frame): * frame.c (adjust_frame_size): * frame.c (store_minibuf_frame_prop): * frame.c (Fframe_property): * frame.c (Fframe_properties): * frame.c (Fframe_displayable_pixel_height): * frame.c (Fframe_displayable_pixel_width): * frame.c (internal_set_frame_size): * frame.c (Fset_frame_height): * frame.c (Fset_frame_pixel_height): * frame.c (Fset_frame_displayable_pixel_height): * frame.c (Fset_frame_width): * frame.c (Fset_frame_pixel_width): * frame.c (Fset_frame_displayable_pixel_width): * frame.c (Fset_frame_size): * frame.c (Fset_frame_pixel_size): * frame.c (Fset_frame_displayable_pixel_size): * frame.c (frame_conversion_internal_1): * frame.c (get_frame_displayable_pixel_size): * frame.c (change_frame_size_1): * frame.c (change_frame_size): * frame.c (generate_title_string): * frame.h: * gtk-xemacs.c: * gtk-xemacs.c (gtk_xemacs_size_request): * gtk-xemacs.c (gtk_xemacs_size_allocate): * gtk-xemacs.c (gtk_xemacs_paint): * gutter.c: * gutter.c (update_gutter_geometry): * redisplay.c (end_hold_frame_size_changes): * redisplay.c (redisplay_frame): * toolbar.c: * toolbar.c (update_frame_toolbars_geometry): * window.c: * window.c (frame_pixsize_valid_p): * window.c (check_frame_size): Various fixes to frame geometry to make it a bit easier to understand and fix some bugs. 1. IMPORTANT: Some renamings. Will need to be applied carefully to the carbon repository, in the following order: -- pixel_to_char_size -> pixel_to_frame_unit_size -- char_to_pixel_size -> frame_unit_to_pixel_size -- pixel_to_real_char_size -> pixel_to_char_size -- char_to_real_pixel_size -> char_to_pixel_size -- Reverse second and third arguments of change_frame_size() and change_frame_size_1() to try to make functions consistent in putting width before height. -- Eliminate old round_size_to_char, because it didn't really do anything differently from round_size_to_real_char() -- round_size_to_real_char -> round_size_to_char; any places that called the old round_size_to_char should just call the new one. 2. IMPORTANT FOR CARBON: The set_frame_size() method is now passed sizes in "frame units", like all other frame-sizing functions, rather than some hacked-up combination of char-cell units and total pixel size. This only affects window systems that use "pixelated geometry", and I'm not sure if Carbon is one of them. MS Windows is pixelated, X and GTK are not. For pixelated-geometry systems, the size in set_frame_size() is in displayable pixels rather than total pixels and needs to be converted appropriately; take a look at the changes made to mswindows_set_frame_size() method if necessary. 3. Add a big long comment in frame.c describing how frame geometry works. 4. Remove MS Windows-specific character height and width fields, duplicative and unused. 5. frame-displayable-pixel-* and set-frame-displayable-pixel-* didn't use to work on MS Windows, but they do now. 6. In general, clean up the handling of "pixelated geometry" so that fewer functions have to worry about this. This is really an abomination that should be removed entirely but that will have to happen later. Fix some buggy code in frame_conversion_internal() that happened to "work" because it was countered by oppositely buggy code in change_frame_size(). 7. Clean up some frame-size code in toolbar.c and use functions already provided in frame.c instead of rolling its own. 8. Fix check_frame_size() in window.c, which formerly didn't take pixelated geometry into account.
author Ben Wing <ben@xemacs.org>
date Mon, 15 Feb 2010 22:14:11 -0600
parents a827a51c3241
children 308d34e9f07d
line wrap: on
line source

-*- indented-text -*-

See the end of this file for copyright information.

This file contains two sections:

1) An EBNF (Extended Backus-Naur Form) description of the format of
    the tags file created by etags.c and interpreted by etags.el;
2) A discussion of tag names and implicit tag names.

====================== 1) EBNF tag file description =====================

Productions created from current behaviour to aid extensions
Francesco Potorti` <pot@gnu.org> 2002
----------------

FF ::= #x0c				   /* tag section starter */

LF ::= #x0a				   /* line terminator */

DEL ::= #x7f				   /* pattern terminator */

SOH ::= #x01				   /* name terminator */

regchar ::= [^#x0a#x0c#x7f]		   /* regular character */

regstring ::= { regchar }		   /* regular string */

unsint ::= [0-9] { [0-9] }		   /* non-negative integer */



tagfile ::= { tagsection }		   /* a tags file */

tagsection ::= FF LF ( includesec | regularsec ) LF

includesec ::= filename ",include" [ LF fileprop ]

regularsec ::= filename "," [ unsint ] [ LF fileprop ] { LF tag }

filename ::= regchar regstring		   /* a file name */

fileprop ::= "(" regstring ")"		   /* an elisp alist */

tag ::= directtag | patterntag

directtag ::= DEL realposition		   /* no pattern */

patterntag ::= pattern DEL [ tagname SOH ] position

pattern ::= regstring			   /* a tag pattern */

tagname ::= regchar regstring		   /* a tag name */

position ::= realposition | "," 	   /* charpos,linepos */

realposition ::= "," unsint | unsint "," | unsint "," unsint

==================== end of EBNF tag file description ====================



======================= 2) discussion of tag names =======================

- WHAT ARE TAG NAMES
Tag lines in a tags file are usually made from the above defined pattern
and by an optional tag name.  The pattern is a string that is searched
in the source file to find the tagged line.

- WHY TAG NAMES ARE GOOD
When a user looks for a tag, Emacs first compares the tag with the tag
names contained in the tags file.  If no match is found, Emacs compares
the tag with the patterns.  The tag name is then the preferred way to
look for tags in the tags file, because when the tag name is present
Emacs can find a tag faster and more accurately.  These tag names are
part of tag lines in the tags file, so we call them "explicit".

- WHY IMPLICIT TAG NAMES ARE EVEN BETTER
When a tag line has no name, but a name can be deduced from the pattern,
we say that the tag line has an implicit tag name.  Often tag names are
redundant; this happens when the name of a tag is an easily guessable
substring of the tag pattern.  We define a set of rules to decide
whether it is possible to deduce the tag name from the pattern, and make
an unnamed tag in those cases.  The name deduced from the pattern of an
unnamed tag is the implicit name of that tag.
  When the user looks for a tag, and Emacs finds no explicit tag names
that match it, Emacs then looks for an tag whose implicit tag name
matches the request.  etags.c uses implicit tag names when possible, in
order to reduce the size of the tags file.
  An implicit tag name is deduced from the pattern by discarding the
last character if it is one of ` \f\t\n\r()=,;', then taking all the
rightmost consecutive characters in the pattern which are not one of
those.

===================== end of discussion of tag names =====================

Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007
Free Software Foundation, Inc.

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