Re: Python API: can I make new prefix Parameters?

Re: Python API: can I make new prefix Parameters?

[Evan Driscoll]

On Thu, Jul 23, 2015 at 6:03 AM, Armando Miraglia <arma2ff0@gmail.com> wrote:
> Hi all, hi Evan.

Hello; thanks for the response. I'll answer a little out of order.

> However, I am not
> complete sure what you need to achieve.
>
> Additionally, I think parameters are meant to work with commands like "set",
> "print" & co out of the box, but if you define your own commands, you can
> associate prefix to group of commands and whatever action to the command you
> want the to perform.

This is indeed what I want to do. I have prefix commands working (e.g.
I can make "foo bar baz on" and "foo bar baz off" work), but I figured
it would be nice for commands that are really just defining settings
to go through Parameters to get things like PARAM_ENUM checking and
registering both set/show implicitly. (I can define set and show
Commands explicitly it seems that would have the same interface to the
user as a Parameter.)


> I believe that the main reason for "print test-param" to work is that
> "print" is actually a command, not a parameter.

That was probably a bad choice of prefix to use; I think that's a red
herring, because there's also a "print" category of settings (e.g.
'set print object' or 'set print pretty'). For example, with the
Parameter below, I can do this:

(gdb) show history test-param
Test doc (show) one
(gdb) set history test-param three
Test doc (set)
(gdb) show history test-param
Test doc (show) three

but again, I can't figure out how to define my own equivalent to "history".

Here's that Parameter:
class TestParameter(gdb.Parameter):
    """The Parameter"""
    def __init__(self):
        super(TestParameter, self).__init__(
            "history test-param",
            gdb.COMMAND_DATA,
            gdb.PARAM_ENUM,
            ["one", "two", "three"])
        self.value = "one"
        self.set_doc = "Test doc (set)"
        self.show_doc = "Test doc (show)"

param = TestParameter()

Evan

Re: Python API: can I make new prefix Parameters?

[Armando Miraglia]

Sorry, I did not reply to the list as well, hence I am writing this again.

On Thu, Jul 23, 2015 at 4:26 PM, Evan Driscoll <evaned@gmail.com> wrote:
> On Thu, Jul 23, 2015 at 6:03 AM, Armando Miraglia <arma2ff0@gmail.com> wrote:
>> Hi all, hi Evan.
>
> Hello; thanks for the response. I'll answer a little out of order.
>
>> However, I am not
>> complete sure what you need to achieve.
>>
>> Additionally, I think parameters are meant to work with commands like "set",
>> "print" & co out of the box, but if you define your own commands, you can
>> associate prefix to group of commands and whatever action to the command you
>> want the to perform.
>
> This is indeed what I want to do. I have prefix commands working (e.g.
> I can make "foo bar baz on" and "foo bar baz off" work), but I figured
> it would be nice for commands that are really just defining settings
> to go through Parameters to get things like PARAM_ENUM checking and
> registering both set/show implicitly. (I can define set and show
> Commands explicitly it seems that would have the same interface to the
> user as a Parameter.)
>
>
>> I believe that the main reason for "print test-param" to work is that
>> "print" is actually a command, not a parameter.
>
> That was probably a bad choice of prefix to use; I think that's a red
> herring, because there's also a "print" category of settings (e.g.
> 'set print object' or 'set print pretty'). For example, with the
> Parameter below, I can do this:
>
> (gdb) show history test-param
> Test doc (show) one
> (gdb) set history test-param three
> Test doc (set)
> (gdb) show history test-param
> Test doc (show) three
>
> but again, I can't figure out how to define my own equivalent to "history".

Again, this is a command :)

try "help show" and "help show history" and you will see that history
is, in fact a command  with its own subcommands (expansion, filename,
save, size), and not a parameter. If you do the same with the
variations of "set print" you provided above,  you can see that "set
print" is also a command, namely print, in this case, is a sub command
of set. To have your own type of "set history" you should do something
like this:

class MyHistory(gdb.Command):
  def __init__(self):
    super(MyHistory, self).__init__("set myhistory", COMMAND_DATA)

  def invoke(self, arg, from_tty):
    # use arg to extract the parameter name and check
    # if it maches your TestParameter name for example, and
    # act on it accordingly. In can also simply use your command
    # as a proxy using parse_and_eval or execute, hence eventually
    # executing "set testparam" instead of "set myhistory testparam"
    pass

I hope this was helpful.

My 2 cents :)
Armando

Re: Python API: can I make new prefix Parameters?

[Evan Driscoll]

On Thu, Jul 23, 2015 at 10:55 AM, Armando Miraglia <arma2ff0@gmail.com> wrote:
> To have your own type of "set history" you should do something
> like this:
>
> class MyHistory(gdb.Command):
>   def __init__(self):
>     super(MyHistory, self).__init__("set myhistory", COMMAND_DATA)
>
>   def invoke(self, arg, from_tty):
>     # use arg to extract the parameter name and check
>     # if it maches your TestParameter name for example, and
>     # act on it accordingly. In can also simply use your command
>     # as a proxy using parse_and_eval or execute, hence eventually
>     # executing "set testparam" instead of "set myhistory testparam"
>     pass
>
> I hope this was helpful.

I appreciate your responses, but I feel we may be talking past each other. :-)

Let's see if I can describe this better. Forgetting about Python-level
Commands vs Parameters, what I want is, from the user's perspective,
for 'set my-category my-setting <arg>' and 'show my-category
my-setting' to work.

Now, I can achieve this in the following manner using gdb.Command:

1. Define a prefix command "set my-category"
2. Define a prefix command "show my-category"
3. Define a non-prefix command "set my-category my-setting"
4. Define a non-prefix command "show my-category my-setting"

But #3 especially is a bit annoying in comparison to using
gdb.Parameter, because I have to take care of a fair bit of stuff
myself. For example, with a Parameter I could use gdb.PARAM_ENUM and
that will automatically provide validation and completion for the set
of permissible values, but I'd have to do that myself if 'set
my-category my-setting <arg>' is a gdb.Command. I also have to define
twice as many Commands as I would if I could say "make a 'my-category'
prefix Parameter" then "make a 'my-category my-setting'" Parameter. So
I'm wondering if there's a better way to do it with gdb.Parameter.

Does that make it clearer what I'm trying to do?


Inspired by your previous email, I also tried the following hybrid approach:

import gdb
class SetPrefixCommand (gdb.Command):
    """Dummy"""
    def __init__(self):
        super(SetPrefixCommand, self).__init__(
            "set my-category",
            gdb.COMMAND_SUPPORT,
            gdb.COMPLETE_NONE,
            True)
SetPrefixCommand()

class ShowPrefixCommand (gdb.Command):
    """Dummy"""
    def __init__(self):
        super(ShowPrefixCommand, self).__init__(
            "show my-category",
            gdb.COMMAND_SUPPORT,
            gdb.COMPLETE_NONE,
            True)
ShowPrefixCommand()

class TestParameter(gdb.Parameter):
    """The Parameter"""
    def __init__(self):
        super(TestParameter, self).__init__(
            "test-category test-param",
            gdb.COMMAND_SUPPORT,
            gdb.PARAM_ENUM,
            ["one", "two", "three"])
        self.value = "one"
        self.set_doc = "Test doc (set)"
        self.show_doc = "Test doc (show)"
param = TestParameter()

but that still gives the same error:

(gdb) source ~/gdb/test_parameter.py
Traceback (most recent call last):
  File "~/gdb/test_parameter.py", line 72, in <module>
  File "~/gdb/test_parameter.py", line 67, in __init__
RuntimeError: Could not find command prefix test-category


Evan

Re: Python API: can I make new prefix Parameters?

[Evan Driscoll]

On Thu, Jul 23, 2015 at 11:09 AM, Evan Driscoll <evaned@gmail.com> wrote:

> but that still gives the same error:
>
> (gdb) source ~/gdb/test_parameter.py
> Traceback (most recent call last):
>   File "~/gdb/test_parameter.py", line 72, in <module>
>   File "~/gdb/test_parameter.py", line 67, in __init__
> RuntimeError: Could not find command prefix test-category

This is still true, by the way, if I fix 'test-category' by changing
it to 'my-category' in TestParameter.__init__. (That mostly just
showed up during my double check and transcription to the email.)

Evan

Re: Python API: can I make new prefix Parameters?

[Evan Driscoll]

On Thu, Jul 23, 2015 at 11:22 AM, Armando Miraglia <arma2ff0@gmail.com> wrote:
> Fixing what you just said, namely renaming "test-category" to "my-category"
> it worked for me:

Oh shoot, I see that now too. I was messing with some other stuff and
didn't completely put it back. I guess I *didn't* try exactly that
permuation before, or made some other similar error.

I think that this might suggest a documentation improvement; if people
are open to the idea, I can write up a proposed change later.

Anyway, thanks for your help!
Evan