Set variable in derived mode before running the parent mode function

Set variable in derived mode before running the parent mode function

[Philipp Stephani]

Hi,

I've defined a derived major mode of `python-mode' using
`define-derived-mode'.  However, some of the variables set by
`python-mode' are inappropriate for the derived mode; in particular, I'd
like to disable auto-guessing of the indentation by setting
`python-indent-guess-indent-offset' to nil.  However,
`define-derived-mode' has no customization point for running code before
the parent mode function.  What's the best way to solve this?  Using an
advice?  Or not using `define-derived-mode' in the first place?

Thanks,
Philipp

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Re: Set variable in derived mode before running the parent mode function

[Stefan Monnier]

> `python-mode' are inappropriate for the derived mode; in particular, I'd
> like to disable auto-guessing of the indentation by setting
> `python-indent-guess-indent-offset' to nil.  However,
> `define-derived-mode' has no customization point for running code before
> the parent mode function.  What's the best way to solve this?

Add the code *after* running python-mode?  After all, setting vars
before would be a waste since python-mode (like all other proper major
modes) begins by calling kill-all-local-variables (also known as
fundamental-mode).


        Stefan

Re: Set variable in derived mode before running the parent mode function

[Andreas Röhler]

Am 03.06.2015 um 03:10 schrieb Stefan Monnier:
>> `python-mode' are inappropriate for the derived mode; in particular, I'd
>> like to disable auto-guessing of the indentation by setting
>> `python-indent-guess-indent-offset' to nil.  However,
>> `define-derived-mode' has no customization point for running code before
>> the parent mode function.  What's the best way to solve this?
> Add the code *after* running python-mode?  After all, setting vars
> before would be a waste since python-mode (like all other proper major
> modes) begins by calling kill-all-local-variables (also known as
> fundamental-mode).
>
>

Can't see this in python.el. python-mode is a derived-mode from prog-mode.

Customizing python-indent-guess-indent-offset to nil should help already.

Andreas

Re: Set variable in derived mode before running the parent mode function

[Stefan Monnier]

>>> `python-mode' are inappropriate for the derived mode; in particular, I'd
>>> like to disable auto-guessing of the indentation by setting
>>> `python-indent-guess-indent-offset' to nil.  However,
>>> `define-derived-mode' has no customization point for running code before
>>> the parent mode function.  What's the best way to solve this?
>> Add the code *after* running python-mode?  After all, setting vars
>> before would be a waste since python-mode (like all other proper major
>> modes) begins by calling kill-all-local-variables (also known as
>> fundamental-mode).
> Can't see this in python.el. python-mode is a derived-mode from prog-mode.

Yup, it starts by calling prog-mode.  Since prog-mode is a proper major
mode it will start by running kill-all-local-variables and hence
python-mode does too.  Of course prog-mode itself is a derived mode so
it doesn't directly call kill-all-local-variables, but instead it calls
fundamental-mode, which itself calls kill-all-local-variables (the two
used to be aliases, but nowadays, fundamental-mode does a little bit
more than just running kill-all-local-variables).


        Stefan

Re: Set variable in derived mode before running the parent mode function

[Philipp Stephani]

Stefan Monnier <monnier@iro.umontreal.ca> schrieb am Mi., 3. Juni 2015 um
03:15 Uhr:

> > `python-mode' are inappropriate for the derived mode; in particular, I'd
> > like to disable auto-guessing of the indentation by setting
> > `python-indent-guess-indent-offset' to nil.  However,
> > `define-derived-mode' has no customization point for running code before
> > the parent mode function.  What's the best way to solve this?
>
> Add the code *after* running python-mode?  After all, setting vars
> before would be a waste since python-mode (like all other proper major
> modes) begins by calling kill-all-local-variables (also known as
> fundamental-mode).
>
>
>
You're right, that wouldn't work. The problem is that
python-indent-guess-indent-offset prints a message if it couldn't guess the
indentation; I'd like to suppress that message.

Re: Set variable in derived mode before running the parent mode function

[Philipp Stephani]

Andreas Röhler <andreas.roehler@easy-emacs.de> schrieb am Do., 4. Juni 2015
um 07:03 Uhr:

> Customizing python-indent-guess-indent-offset to nil should help already.
>

Yes, but it would apply to all Python files as well, not only to the
derived mode.

Re: Set variable in derived mode before running the parent mode function

[Andreas Röhler]

Am 06.06.2015 um 17:59 schrieb Philipp Stephani:
>
>
> Andreas Röhler <andreas.roehler@easy-emacs.de 
> <mailto:andreas.roehler@easy-emacs.de>> schrieb am Do., 4. Juni 2015 
> um 07:03 Uhr:
>
>     Customizing python-indent-guess-indent-offset to nil should help
>     already.
>
>
> Yes, but it would apply to all Python files as well, not only to the 
> derived mode.

Only the --derived-- python-mode asks for variable

python-indent-guess-indent-offset

and does (python-indent-guess-indent-offset) if t

Re: Set variable in derived mode before running the parent mode function

[Andreas Röhler]

Am 06.06.2015 um 17:58 schrieb Philipp Stephani:
> Stefan Monnier <monnier@iro.umontreal.ca> schrieb am Mi., 3. Juni 2015 um
> 03:15 Uhr:
>
>>> `python-mode' are inappropriate for the derived mode; in particular, I'd
>>> like to disable auto-guessing of the indentation by setting
>>> `python-indent-guess-indent-offset' to nil.  However,
>>> `define-derived-mode' has no customization point for running code before
>>> the parent mode function.  What's the best way to solve this?
>> Add the code *after* running python-mode?  After all, setting vars
>> before would be a waste since python-mode (like all other proper major
>> modes) begins by calling kill-all-local-variables (also known as
>> fundamental-mode).
>>
>>
>>
> You're right, that wouldn't work. The problem is that
> python-indent-guess-indent-offset prints a message if it couldn't guess the
> indentation; I'd like to suppress that message.


Disabling a message is another thing than disabling auto-guessing.

Look into python.el, definition of

python-indent-guess-indent-offset

Messaging is done from last line there. Put it at an extra line - i.e. a 
new line at the end of "(message
" sexp. Than comment out that line.

Re: Set variable in derived mode before running the parent mode function

[Philipp Stephani]

Andreas Röhler <andreas.roehler@easy-emacs.de> schrieb am So., 7. Juni 2015
um 13:52 Uhr:

>
> Am 06.06.2015 um 17:58 schrieb Philipp Stephani:
> > Stefan Monnier <monnier@iro.umontreal.ca> schrieb am Mi., 3. Juni 2015
> um
> > 03:15 Uhr:
> >
> >>> `python-mode' are inappropriate for the derived mode; in particular,
> I'd
> >>> like to disable auto-guessing of the indentation by setting
> >>> `python-indent-guess-indent-offset' to nil.  However,
> >>> `define-derived-mode' has no customization point for running code
> before
> >>> the parent mode function.  What's the best way to solve this?
> >> Add the code *after* running python-mode?  After all, setting vars
> >> before would be a waste since python-mode (like all other proper major
> >> modes) begins by calling kill-all-local-variables (also known as
> >> fundamental-mode).
> >>
> >>
> >>
> > You're right, that wouldn't work. The problem is that
> > python-indent-guess-indent-offset prints a message if it couldn't guess
> the
> > indentation; I'd like to suppress that message.
>
>
> Disabling a message is another thing than disabling auto-guessing.
>
> Look into python.el, definition of
>
> python-indent-guess-indent-offset
>
> Messaging is done from last line there. Put it at an extra line - i.e. a
> new line at the end of "(message
> " sexp. Than comment out that line.
>
>
Sure, but that would disable the message for all users. I could totally
live with that (Emacs is already too chatty), but Stefan would need to
agree that it's fine to remove the message entirely.

Re: Set variable in derived mode before running the parent mode function

[Stefan Monnier]

> live with that (Emacs is already too chatty), but Stefan would need to
> agree that it's fine to remove the message entirely.

I have no opinion on this.  You should talk the python.el's
maintainer instead.


        Stefan

Re: Set variable in derived mode before running the parent mode function

[Philipp Stephani]

Stefan Monnier <monnier@iro.umontreal.ca> schrieb am So., 21. Juni 2015 um
19:35 Uhr:

> > live with that (Emacs is already too chatty), but Stefan would need to
> > agree that it's fine to remove the message entirely.
>
> I have no opinion on this.  You should talk the python.el's
> maintainer instead.
>
>
Actually there's already a variable
`python-indent-guess-indent-offset-verbose' (introduced in commit
1d02107dab6f844a7c537bb5e98aff4e5f061246), which should resolve this issue.