[RFAv4,3/3] NEWS and documentation for default-args related concept and commands.
Commit Message
gdb/ChangeLog
YYYY-MM-DD Philippe Waroquiers <philippe.waroquiers@skynet.be>
* NEWS: Mention new default-args commands. Mention change
to the alias command.
gdb/doc/ChangeLog
YYYY-MM-DD Philippe Waroquiers <philippe.waroquiers@skynet.be>
* gdb.texinfo (Command default args): New node documenting
'set|show default-args' and 'set|show enable-default-args'.
(Aliases): Document the new 'DEFAULT-ARGS...' option.
---
gdb/NEWS | 27 ++++++++++
gdb/doc/gdb.texinfo | 126 +++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 152 insertions(+), 1 deletion(-)
Comments
> From: Philippe Waroquiers <philippe.waroquiers@skynet.be>
> Cc: Philippe Waroquiers <philippe.waroquiers@skynet.be>
> Date: Sat, 8 Feb 2020 15:09:13 +0100
>
> gdb/ChangeLog
> YYYY-MM-DD Philippe Waroquiers <philippe.waroquiers@skynet.be>
>
> * NEWS: Mention new default-args commands. Mention change
> to the alias command.
>
> gdb/doc/ChangeLog
> YYYY-MM-DD Philippe Waroquiers <philippe.waroquiers@skynet.be>
>
> * gdb.texinfo (Command default args): New node documenting
> 'set|show default-args' and 'set|show enable-default-args'.
> (Aliases): Document the new 'DEFAULT-ARGS...' option.
> ---
> gdb/NEWS | 27 ++++++++++
> gdb/doc/gdb.texinfo | 126 +++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 152 insertions(+), 1 deletion(-)
>
> diff --git a/gdb/NEWS b/gdb/NEWS
> index d4e2e70f38..a59f9573fd 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -23,6 +23,33 @@ show exec-file-mismatch -- Show exec-file-mismatch handling (ask|warn|off).
> whether to load the process executable file; if 'warn', just display
> a warning; if 'off', don't attempt to detect a mismatch.
>
> +set default-args COMMAND [DEFAULT-ARGS...]
> +show default-args [COMMAND]
> +set enable-default-args [on|off]
> +show enable-default-args
> + GDB can now automatically prepend default args to a command or alias.
Since we seem to be splitting hair now, at least in the documentation
parts: "prepending ... args to a command" doesn't sound right. You
actually prepend the default arguments to the command's list of
arguments, right?
> +You can tell @value{GDBN} to always add some default options or
> +arguments to a command.
Same issue here.
> +If you repetitively use the same arguments or options for a command,
^^^^^^^^^^^^
"repeatedly" sounds better here.
> +@smallexample
> +(@value{GDBP}) alias bt_ALL = backtrace -entry-values both -frame-arg all \
> +-past-main -past-entry -full
Suggest to indent the second line of the example, to make it more
evident that it's a continuation of the previous line.
> +This is also very useful to define an alias for a set of nested @code{with}
> +commands to have a particular combination of temporary settings. For example,
> +the below defines the alias @code{pp10} that pretty prints an expression
> +argument, with a maximum of 10 elements if the expression is a string or
> +an array:
> +@smallexample
> +(@value{GDBP}) alias pp10 = with print pretty -- with print elem 10 -- print
> +@end smallexample
I must admit I don't understand this particular feature. What does
"with" signify here, and what is the significance of the "--" parts?
IOW, it would help if you deconstructed this example some more,
showing what each part of it does.
> +This can be disabled using @code{set enable-default-args off}.
> +The default args of all commands are not cleared, but
"not cleared by @code{set enable-default-args off}" makes this
sentence more clear, IMO.
And one more question that popped up while reading this: when I invoke
a command that has some default args defined for it, what is recorded
in command history? the full command with the default args, or just
what I typed?
Thanks.
@@ -23,6 +23,33 @@ show exec-file-mismatch -- Show exec-file-mismatch handling (ask|warn|off).
whether to load the process executable file; if 'warn', just display
a warning; if 'off', don't attempt to detect a mismatch.
+set default-args COMMAND [DEFAULT-ARGS...]
+show default-args [COMMAND]
+set enable-default-args [on|off]
+show enable-default-args
+ GDB can now automatically prepend default args to a command or alias.
+ This allows to set default arguments or options for the GDB commands
+ or define easily more specialised aliases.
+ For example, 'set default-args backtrace -full -frame-arguments all'
+ ensures that backtrace will automatically use the options -full
+ -frame-arguments all, without having to retype them for each backtrace
+ command.
+
+* Changed commands
+
+alias [-a] [--] ALIAS = COMMAND [DEFAULT-ARGS...]
+ The alias command can now directly define default-args
+ to prepend to arguments provided by the user on the command line.
+ For example, to have a backtrace with full details, you can define an
+ alias 'bt_ALL' as 'alias bt_ALL = backtrace -entry-values both -frame-arg
+ all -past-main -past-entry -full'.
+ Alias default arguments can also use a set of nested 'with' commands,
+ e.g. 'alias pp10 = with print pretty -- with print elem 10 -- print'
+ defines the alias pp10 that will pretty print a maximum of 10 elements
+ of the given expression (if the expression is an array).
+ See 'set default-args COMMAND [DEFAULT-ARGS...]' for more
+ information about default args concept.
+
*** Changes in GDB 9
* 'thread-exited' event is now available in the annotations interface.
@@ -1577,6 +1577,7 @@ show you the alternatives available, if there is more than one possibility).
* Command Settings:: How to change default behavior of commands
* Completion:: Command completion
* Command Options:: Command options
+* Command default args:: Automatically prepend default arguments to commands and aliases
* Help:: How to ask @value{GDBN} for help
@end menu
@@ -1997,6 +1998,116 @@ uppercase.
(For more on using the @code{print} command, see @ref{Data, ,Examining
Data}.)
+@node Command default args
+@section Automatically prepend default arguments to commands and aliases
+
+You can tell @value{GDBN} to always add some default options or
+arguments to a command.
+
+@cindex command options, automatically prepend
+@cindex command, default arguments
+
+@table @code
+@kindex set default-args
+@item set default-args @var{command} [@var{default-args@dots{}}]
+
+If you repetitively use the same arguments or options for a command,
+you can tell @value{GDBN} to automatically prepend these arguments
+or options to the arguments you type explicitely.
+
+For example, if you always want to have the command @code{thread apply all}
+working on the threads in ascending order and to continue in case it
+encounters an error, you can tell @value{GDBN} to automatically preprend
+the @code{-ascending} and @code{-c} options by using:
+
+@smallexample
+(@value{GDBP}) set default-args thread apply all -ascending -c
+@end smallexample
+
+Once you have set these default args, any time you type
+the @code{thread apply all} followed by @code{some arguments},
+@value{GDBN} will execute @code{thread apply all -ascending -c some arguments}.
+
+As usual, unambiguous abbreviations can be used for @var{command}
+and @var{default-args}.
+
+Commands and their aliases do not share their default args.
+So, for example, you can configure the commands @code{bt}, @code{where},
+@code{backtrace} and @code{info stack} to output different levels
+of information and define a new alias @code{bt_ALL} showing all possible
+information using:
+@smallexample
+(@value{GDBP}) set default-args bt -entry-values no -frame-arguments none
+(@value{GDBP}) set default-args where -entry-values no -frame-argu scalars
+(@value{GDBP}) set default-args backtrace -entry-values no -frame-argu all
+(@value{GDBP}) set default-args info stack -entry-val both -fr all
+(@value{GDBP}) alias bt_ALL = backtrace
+(@value{GDBP}) set default-args bt_ALL -entry-values both -frame-arg all \
+-past-main -past-entry -full
+@end smallexample
+
+You can define an alias and specify its default args in one command using the shorter to type:
+@smallexample
+(@value{GDBP}) alias bt_ALL = backtrace -entry-values both -frame-arg all \
+-past-main -past-entry -full
+@end smallexample
+(For more on using the @code{alias} command, see @ref{Aliases}.)
+
+Default args are not limited to the arguments and options of @var{command},
+but can specify nested commands if @var{command} accepts such a nested command
+as argument.
+For example, the below defines @code{faalocalsoftype} that can be used to list
+the frames having locals of a certain type, together with the matching local
+vars:
+@smallexample
+(@value{GDBP}) alias faalocalsoftype = frame apply all info locals -q -t
+(@value{GDBP}) faalocalsoftype int
+#1 0x55554f5e in sleeper_or_burner (v=0xdf50) at sleepers.c:86
+i = 0
+ret = 21845
+@end smallexample
+
+This is also very useful to define an alias for a set of nested @code{with}
+commands to have a particular combination of temporary settings. For example,
+the below defines the alias @code{pp10} that pretty prints an expression
+argument, with a maximum of 10 elements if the expression is a string or
+an array:
+@smallexample
+(@value{GDBP}) alias pp10 = with print pretty -- with print elem 10 -- print
+@end smallexample
+
+
+Use @code{set default-args @var{command}} (without giving @var{default-args})
+to clear the default args of @var{command}.
+
+@item show default-args [@var{command}]
+
+Use @code{show default-args @var{command}} to show the current values of
+the default args for @var{command}. For example:
+@smallexample
+(@value{GDBP}) show default-args backtrace
+default-args backtrace = -entry-values no -frame-arguments all
+(@value{GDBP}) show default-args break
+default-args break = <no default args>
+@end smallexample
+
+To show all the commands and aliases that have some default args configured,
+use the command
+@code{show default-args} without giving a @var{command} argument.
+
+@item set enable-default-args @r{[}on|off@r{]}
+@itemx show enable-default-args
+By default, @value{GDBN} will use the configured default args.
+This can be disabled using @code{set enable-default-args off}.
+The default args of all commands are not cleared, but
+will not be used till you do @code{set enable-default-args on}.
+This can be useful in user defined commands to ensure only the specified
+set of options are used by a command launched by the user-defined command.
+You can also use this setting in the @code{with} command, to temporarily
+run a command without its possibly configured default args.
+
+@end table
+
@node Help
@section Getting Help
@cindex online documentation
@@ -27481,7 +27592,7 @@ You can define a new alias with the @samp{alias} command.
@table @code
@kindex alias
-@item alias [-a] [--] @var{ALIAS} = @var{COMMAND}
+@item alias [-a] [--] @var{ALIAS} = @var{COMMAND} [DEFAULT-ARGS...]
@end table
@@ -27499,6 +27610,19 @@ lists displayed by the @samp{help} command.
The @samp{--} option specifies the end of options,
and is useful when @var{ALIAS} begins with a dash.
+You can specify @var{default-args} for your alias.
+These @var{default-args} will be automatically added before the alias
+arguments typed explicitely on the command line.
+
+For example, the below defines an alias @code{btfullall} that shows all local
+variables and all frame arguments:
+@smallexample
+(@value{GDBP}) alias btfullall = backtrace -full -frame-arguments all
+@end smallexample
+
+For more information about @var{default-args}, see @ref{Command default args,
+,Automatically prepend default arguments to commands and aliases}
+
Here is a simple example showing how to make an abbreviation
of a command so that there is less to type.
Suppose you were tired of typing @samp{disas}, the current