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

[Evan Driscoll <evaned@gmail.com>]

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