[binutils-gdb] gdb/doc: update syntax of -data-disassemble command arguments

[Andrew Burgess <aburgess@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=48883ade64759b72aa876d6255796c8e66429be8

commit 48883ade64759b72aa876d6255796c8e66429be8
Author: Andrew Burgess <aburgess@redhat.com>
Date:   Thu Jun 23 13:57:57 2022 +0100

    gdb/doc: update syntax of -data-disassemble command arguments
    
    The argument documentation for -data-disassemble looks like this:
    
       -data-disassemble
          [ -s @var{start-addr} -e @var{end-addr} ]
        | [ -a @var{addr} ]
        | [ -f @var{filename} -l @var{linenum} [ -n @var{lines} ] ]
        -- @var{mode}
    
    However, I believe, according to the 'Notation and Terminology'
    section, this means that the there are 3 optional location
    specification argument groups for the command, followed by a
    non-optional '-- mode'.
    
    However, this is not true, one of the location specifications must be
    given, i.e. we can't choose to give NO location specification, which
    is what the above implies.
    
    I propose that we change this to instead be:
    
       -data-disassemble
        ( -s @var{start-addr} -e @var{end-addr}
        | -a @var{addr}
        | -f @var{filename} -l @var{linenum} [ -n @var{lines} ] )
        -- @var{mode}
    
    By placing all the location specifications within '( ... )' we
    indication that these are a group, from which one of the options,
    separated by '|', must be selected.
    
    However, the 'Notation and Terminology' section only describes two
    uses for parenthesis: '( GROUP )*' and '( GROUP )+', in the first case
    GROUP is repeated zero or more times, and in the second GROUP is
    repeated 1 or more times.
    
    Neither of those exactly describe what I want, which is GROUP must
    appear exactly once.  I propose to extend 'Notation and Terminology'
    to include '( GROUP )' which means that GROUP should appear exactly
    once.
    
    This change is important because, in a later commit, I want to add
    additional optional arguments to the -data-disassemble command, and
    things start to get confusing with the original syntax.

Diff:
---
 gdb/doc/gdb.texinfo | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 596e5873558..afe29a9a025 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -29910,6 +29910,10 @@ may repeat zero or more times.
 @code{( @var{group} )+} means that @var{group} inside the parentheses
 may repeat one or more times.
 
+@item
+@code{( @var{group} )} means that @var{group} inside the parentheses
+occurs exactly once.
+
 @item
 @code{"@var{string}"} means a literal @var{string}.
 @end itemize
@@ -34580,9 +34584,9 @@ For details about what an addressable memory unit is,
 
 @smallexample
  -data-disassemble
-    [ -s @var{start-addr} -e @var{end-addr} ]
-  | [ -a @var{addr} ]
-  | [ -f @var{filename} -l @var{linenum} [ -n @var{lines} ] ]
+  ( -s @var{start-addr} -e @var{end-addr}
+  | -a @var{addr}
+  | -f @var{filename} -l @var{linenum} [ -n @var{lines} ] )
   -- @var{mode}
 @end smallexample