[PATCH v6 3/8] GDB: Add `NUMBER' completion to `set' integer commands

["Maciej W. Rozycki" <macro@embecosm.com>]

Fix a completion consistency issue with `set' commands accepting integer 
values and the special `unlimited' keyword:

(gdb) complete print -elements
print -elements NUMBER
print -elements unlimited
(gdb)

vs:

(gdb) complete set print elements
set print elements unlimited
(gdb)

(there is a space entered at the end of both commands, not shown here) 
which also means if you strike <Tab> with `set print elements ' input, 
it will, annoyingly, complete to `set print elements unlimited' right 
away rather than showing a choice between `NUMBER' and `unlimited'.

Add `NUMBER' then as an available completion for such `set' commands:

(gdb) complete set print elements
set print elements NUMBER
set print elements unlimited
(gdb)
  
Adjust the testsuite accordingly.  Also document the feature in the 
Completion section of the manual in addition to the Command Options 
section already there.
---
On Fri, 24 Jun 2022, Andrew Burgess wrote:

> > Add `NUMBER' then as an available completion for such `set' commands:
> >
> > (gdb) complete set print elements
> > set print elements NUMBER
> > set print elements unlimited
> > (gdb)
> >   
> > Adjust the testsuite accordingly.
> 
> I like this change, but I think we should add some documentation in
> `@node Completion` that describes this new behaviour. We should probably
> add a NEWS entry too.

 Thank you for your review.

 This is already documented in the Command Options section, but that's not 
necessarily the place one will look for it, so maybe it's worth repeating 
here as well indeed.  I have changed the wording slightly compared to the 
original.

 How about this version then?

  Maciej

Changes from v5:

- document the `NUMBER' completion in the Completion section of the manual
  for commands accepting keywords as well as numbers,

- document the addition of `NUMBER' completion for `set' commands in NEWS.

No change from v4.

New change in v4.
---
 gdb/NEWS                            |   12 ++++++++++++
 gdb/cli/cli-decode.c                |    2 ++
 gdb/doc/gdb.texinfo                 |   15 +++++++++++++++
 gdb/testsuite/gdb.base/settings.exp |    8 +++++++-
 4 files changed, 36 insertions(+), 1 deletion(-)

gdb-integer-complete-number.diff
Index: src/gdb/NEWS
===================================================================
--- src.orig/gdb/NEWS
+++ src/gdb/NEWS
@@ -27,6 +27,18 @@
   emit to indicate where a breakpoint should be placed to break in a function
   past its prologue.
 
+* Completion now also offers "NUMBER" for "set" commands that accept
+  a numeric argument and the "unlimited" keyword.  For example:
+
+   (gdb) set width <TAB>
+   NUMBER     unlimited
+
+  and consequently:
+
+   (gdb) complete set width
+   set width NUMBER
+   set width unlimited
+
 * New commands
 
 maintenance set ignore-prologue-end-flag on|off
Index: src/gdb/cli/cli-decode.c
===================================================================
--- src.orig/gdb/cli/cli-decode.c
+++ src/gdb/cli/cli-decode.c
@@ -989,6 +989,8 @@ integer_unlimited_completer (struct cmd_
       NULL,
     };
 
+  if (*text == '\0')
+    tracker.add_completion (make_unique_xstrdup ("NUMBER"));
   complete_on_enum (tracker, keywords, text, word);
 }
 
Index: src/gdb/doc/gdb.texinfo
===================================================================
--- src.orig/gdb/doc/gdb.texinfo
+++ src/gdb/doc/gdb.texinfo
@@ -1960,6 +1960,21 @@ After displaying the available possibili
 partial input (@samp{b make_} in the example) so you can finish the
 command.
 
+If the command you are trying to complete expects either a keyword or a
+number to follow, then @samp{NUMBER} will be shown among the available
+completions, for example:
+
+@smallexample
+(@value{GDBP}) print -elements @key{TAB}@key{TAB}
+NUMBER     unlimited
+(@value{GDBP}) print -elements@tie{}
+@end smallexample
+
+@noindent
+Here, the option expects a number (e.g., @code{100}), not literal
+@code{NUMBER}.  Such metasyntactical arguments are always presented in
+uppercase.
+
 If you just want to see the list of alternatives in the first place, you
 can press @kbd{M-?} rather than pressing @key{TAB} twice.  @kbd{M-?}
 means @kbd{@key{META} ?}.  You can type this either by holding down a
Index: src/gdb/testsuite/gdb.base/settings.exp
===================================================================
--- src.orig/gdb/testsuite/gdb.base/settings.exp
+++ src/gdb/testsuite/gdb.base/settings.exp
@@ -215,8 +215,14 @@ proc test-integer {variant} {
 	test_gdb_complete_none \
 	    "$set_cmd "
     } else {
+	test_gdb_complete_multiple "$set_cmd " "" "" {
+	    "NUMBER"
+	    "unlimited"
+	}
+	test_gdb_complete_none \
+	    "$set_cmd 1"
 	test_gdb_complete_unique \
-	    "$set_cmd " \
+	    "$set_cmd u" \
 	    "$set_cmd unlimited"
     }