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readline trick needed

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  readline trick needed Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-13 13:30 +0000
    Re: readline trick needed Etienne Robillard <animelovin@gmail.com> - 2012-10-13 09:44 -0400
    Re: readline trick needed Chris Angelico <rosuav@gmail.com> - 2012-10-14 00:47 +1100
    Re: readline trick needed Etienne Robillard <animelovin@gmail.com> - 2012-10-13 09:58 -0400
    Re: readline trick needed Roel Schroeven <roel@roelschroeven.net> - 2012-10-13 23:14 +0200
    Re: readline trick needed Chris Angelico <rosuav@gmail.com> - 2012-10-14 08:44 +1100
    Re: readline trick needed Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-10-13 23:13 +0100
    Re: readline trick needed Chris Angelico <rosuav@gmail.com> - 2012-10-14 09:41 +1100
    Re: readline trick needed Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-10-13 23:52 +0100
    Re: readline trick needed Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-10-14 01:32 +0100
    [on topic] Re: readline trick needed Peter Otten <__peter__@web.de> - 2012-10-16 10:30 +0200
      Re: [on topic] Re: readline trick needed Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-16 11:27 +0000
        Re: [on topic] Re: readline trick needed Robert Kern <robert.kern@gmail.com> - 2012-10-16 13:20 +0100
          Re: [on topic] Re: readline trick needed Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-16 12:52 +0000
        Re: [on topic] Re: readline trick needed Dwight Hutto <dwightdhutto@gmail.com> - 2012-10-16 10:14 -0400
        [off topic], was Re: [on topic] Re: readline trick needed Peter Otten <__peter__@web.de> - 2012-10-16 16:36 +0200
        Re: [off topic], was Re: [on topic] Re: readline trick needed Dwight Hutto <dwightdhutto@gmail.com> - 2012-10-16 11:14 -0400
    Re: [on topic] Re: readline trick needed Ned Deily <nad@acm.org> - 2012-10-16 01:50 -0700
    Re: [on topic] Re: readline trick needed Peter Otten <__peter__@web.de> - 2012-10-16 12:20 +0200
    Re: [on topic] Re: readline trick needed Ned Deily <nad@acm.org> - 2012-10-16 13:44 -0700

#31192 — readline trick needed

I'm working with the readline module, and I'm trying to set a key 
combination to process the current command line by calling a known 
function, *and* enter the command line.

Something along the lines of:

* execute function spam() in some context where it can access 
  the current command line as a string
* enter the command line

Function spam() may or may not modify the command line.

Here is what I have got so far: I can discard the current line and call a 
function:

readline.parse_and_bind(r'"\C-p": "%cspam()\n"' % 0x15)  # ^U

binds ctrl-P to the key combinations `ctrl-U spam() Enter`, which clears 
the command line before entering spam().

If I leave out the ctrl-U, I'll get a SyntaxError or other exception, 
e.g. command line `x = 123` gets transformed into `x = 123spam()`.


This is not suitable:

readline.parse_and_bind(r'"\C-p": "; spam()\n"')

because it changes the command line. It's okay for spam() itself to 
modify the command line, but the key binding should not.

I tried to do this:

readline.parse_and_bind(r'"\C-p": "\nspam()\n"')

but it gives me a segmentation fault, which is a little less helpful than 
I had expected.

This Stackoverflow question suggests that what I want is not possible in 
vanilla Python:

http://stackoverflow.com/questions/11680356


but I'm a stubborn guy and I have not given up yet. Any suggestions?


(P.S. I'm aware of IPython, I want to get this working in the standard 
CPython interpreter.)


-- 
Steven

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#31194

On 13 Oct 2012 13:30:14 GMT
Steven D'Aprano <steve+comp.lang.python@pearwood.info> wrote:

> I'm working with the readline module, and I'm trying to set a key 
> combination to process the current command line by calling a known 
> function, *and* enter the command line.
> 
> Something along the lines of:
> 
> * execute function spam() in some context where it can access 
>   the current command line as a string
> * enter the command line
> 
> Function spam() may or may not modify the command line.
> 
> Here is what I have got so far: I can discard the current line and call a 
> function:
> 
> readline.parse_and_bind(r'"\C-p": "%cspam()\n"' % 0x15)  # ^U
> 
> binds ctrl-P to the key combinations `ctrl-U spam() Enter`, which clears 
> the command line before entering spam().
> 
> If I leave out the ctrl-U, I'll get a SyntaxError or other exception, 
> e.g. command line `x = 123` gets transformed into `x = 123spam()`.
> 
> 
> This is not suitable:
> 
> readline.parse_and_bind(r'"\C-p": "; spam()\n"')
> 
> because it changes the command line. It's okay for spam() itself to 
> modify the command line, but the key binding should not.
> 
> I tried to do this:
> 
> readline.parse_and_bind(r'"\C-p": "\nspam()\n"')
> 
> but it gives me a segmentation fault, which is a little less helpful than 
> I had expected.
> 
> This Stackoverflow question suggests that what I want is not possible in 
> vanilla Python:
> 
> http://stackoverflow.com/questions/11680356
> 
> 
> but I'm a stubborn guy and I have not given up yet. Any suggestions?
> 
> 
> (P.S. I'm aware of IPython, I want to get this working in the standard 
> CPython interpreter.)
> 
> 
> -- 
> Steven
> -- 
> http://mail.python.org/mailman/listinfo/python-list


Why dont you grow yourself some usable neurons instead ? Don't you realize now stackoverflow.com is starting
to hurt your capacity to cogitate on your own or have you not realized this yet?

Cheers,

Etienne


-- 
Etienne Robillard
Green Tea Hackers Club
Fine Software Carpentry For The Rest Of Us!
http://gthc.org/
erob@gthcfoundation.org

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#31195

On Sun, Oct 14, 2012 at 12:44 AM, Etienne Robillard
<animelovin@gmail.com> wrote:
> Why dont you grow yourself some usable neurons instead ? Don't you realize now stackoverflow.com is starting
> to hurt your capacity to cogitate on your own or have you not realized this yet?

Excuse me?

I'm not overly familiar with readline, so perhaps there is a really
obvious way to do what Steven's trying to do, but this post does not
appear to be the result of a lack of thinking.

If it really IS that obvious to you, post a link to appropriate
documentation without the rudeness... that way it'll be useful to
everyone, not just cathartic to you.

ChrisA

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#31196

On Sun, 14 Oct 2012 00:47:52 +1100
Chris Angelico <rosuav@gmail.com> wrote:

> Excuse me?
> 
> I'm not overly familiar with readline, so perhaps there is a really
> obvious way to do what Steven's trying to do, but this post does not
> appear to be the result of a lack of thinking.
> 
> If it really IS that obvious to you, post a link to appropriate
> documentation without the rudeness... that way it'll be useful to
> everyone, not just cathartic to you.
> 
> ChrisA
> -- 
> http://mail.python.org/mailman/listinfo/python-list

whatever. i don't feel much like replying to idiots today so your apologies
and useless if not irrelevant. 



-- 
Etienne Robillard
Green Tea Hackers Club
Fine Software Carpentry For The Rest Of Us!
http://gthc.org/
erob@gthcfoundation.org

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#31219

Etienne Robillard schreef:
> On Sun, 14 Oct 2012 00:47:52 +1100
> Chris Angelico <rosuav@gmail.com> wrote:
> 
>> Excuse me?
>>
>> I'm not overly familiar with readline, so perhaps there is a really
>> obvious way to do what Steven's trying to do, but this post does not
>> appear to be the result of a lack of thinking.
>>
>> If it really IS that obvious to you, post a link to appropriate
>> documentation without the rudeness... that way it'll be useful to
>> everyone, not just cathartic to you.
>>
>> ChrisA
>> -- 
>> http://mail.python.org/mailman/listinfo/python-list
> 
> whatever. i don't feel much like replying to idiots today

Then simply don't. Much better then replying in such a rude way.

I leave the question of who is being an idiot here as an exercise to the 
reader.

-- 
"Too often we hold fast to the cliches of our forebears. We subject all
facts to a prefabricated set of interpretations. Too often we enjoy the
comfort of opinion without the discomfort of thought."
         -- John F Kennedy

roel@roelschroeven.net

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#31222

On Sun, Oct 14, 2012 at 8:31 AM, Joshua Landau
<joshua.landau.ws@gmail.com> wrote:
> With two irritants (including 88888), is it not advisable that python-list
> gets an admin to block these accounts? Even if it does nothing more than
> slow them, that's something.

That's what killfiles are for. You have two options:

http://en.wikipedia.org/wiki/Kill_file
http://bofh.ch/bofh/bsmh2.html

The first option is not perfect, as you'll still see replies that
quote such people's posts. The second has a few issues with local law
enforcement, but other than that, is a very effective means of
avoiding seeing their posts.

ChrisA

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#31224

On 13/10/2012 22:31, Joshua Landau wrote:
>
> With two irritants (including 88888), is it not advisable that python-list
> gets an admin to block these accounts? Even if it does nothing more than
> slow them, that's something.
>

Most irritants are mere amateurs compared to Ilias Lazaridis.  I wonder 
if he's *STILL* researching?

-- 
Cheers.

Mark Lawrence.

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#31227

On Sun, Oct 14, 2012 at 9:25 AM, Joshua Landau
<joshua.landau.ws@gmail.com> wrote:
> On 13 October 2012 22:44, Chris Angelico <rosuav@gmail.com> wrote:
>>
>> On Sun, Oct 14, 2012 at 8:31 AM, Joshua Landau
>> <joshua.landau.ws@gmail.com> wrote:
>> > With two irritants (including 88888), is it not advisable that
>> > python-list
>> > gets an admin to block these accounts? Even if it does nothing more than
>> > slow them, that's something.
>>
>> That's what killfiles are for. You have two options:
>>
>> http://en.wikipedia.org/wiki/Kill_file
>> http://bofh.ch/bofh/bsmh2.html
>>
>> The first option is not perfect, as you'll still see replies that
>> quote such people's posts. The second has a few issues with local law
>> enforcement, but other than that, is a very effective means of
>> avoiding seeing their posts.
>
>
> The first's no good for protecting the newbies though. If troll flames
> newbie, then I want to be able to assure newbie that he's not done anything
> wrong or stupid.
>
> The second is a bit better, definitely, but what I'm wanting is to delegate
> these tasks to python-list's admins. I'm lazy, see.

Agreed, defending newbies is important. But not everyone gets
frustrated at trolls. Those who don't, don't bother to killfile them,
and can respond in defense of the newbies. Also, if two or three
non-trolls respond to the original post, the angry troll is only one
of several, which helps dilute the problem a bit. Still not a
solution, but it helps.

ChrisA

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#31228

On 13/10/2012 23:26, Joshua Landau wrote:
> On 13 October 2012 23:13, Mark Lawrence <breamoreboy@yahoo.co.uk> wrote:
>
>> On 13/10/2012 22:31, Joshua Landau wrote:
>>
>>>
>>> With two irritants (including 88888), is it not advisable that python-list
>>> gets an admin to block these accounts? Even if it does nothing more than
>>> slow them, that's something.
>>>
>>>
>> Most irritants are mere amateurs compared to Ilias Lazaridis.  I wonder if
>> he's *STILL* researching?
>
>
> My god, he even has an encyclopaedia
> entry<http://www.nationmaster.com/encyclopedia/Ilias-Lazaridis>.
> Is he some kind of deity?
>

Oh no he's far higher up the food chain than that.  Here's a starter
https://groups.google.com/forum/?fromgroups=#!search/lazaridis$20banned/comp.lang.ruby/plR34TbM3vc/Ev-Hj5F8oKcJ

-- 
Cheers.

Mark Lawrence.

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#31230

On 13/10/2012 23:52, Mark Lawrence wrote:
> On 13/10/2012 23:26, Joshua Landau wrote:
>> On 13 October 2012 23:13, Mark Lawrence <breamoreboy@yahoo.co.uk> wrote:
>>
>>> On 13/10/2012 22:31, Joshua Landau wrote:
>>>
>>>>
>>>> With two irritants (including 88888), is it not advisable that
>>>> python-list
>>>> gets an admin to block these accounts? Even if it does nothing more
>>>> than
>>>> slow them, that's something.
>>>>
>>>>
>>> Most irritants are mere amateurs compared to Ilias Lazaridis.  I
>>> wonder if
>>> he's *STILL* researching?
>>
>>
>> My god, he even has an encyclopaedia
>> entry<http://www.nationmaster.com/encyclopedia/Ilias-Lazaridis>.
>> Is he some kind of deity?
>>
>
> Oh no he's far higher up the food chain than that.  Here's a starter
> https://groups.google.com/forum/?fromgroups=#!search/lazaridis$20banned/comp.lang.ruby/plR34TbM3vc/Ev-Hj5F8oKcJ
>
>

Yes a real pro.  Trolling will never become an Olympic sport as the 
guy's so good nobody can compete with him.  (If he was American they'd 
still have a World Series though :)  Throw his name plus Eclipse, 
Netbeans and banned into your search engine of choice and enjoy, but 
beware that to really endulge yourself please stock up on vast 
quantities of caffeine and sandwiches first cos you'll need them.  For 
example this http://web.archiveorange.com/archive/v/7IfPlywrYZb0gAgMsPa1 
points to this http://www.tfeb.org/lisp/mad-people.html

-- 
Cheers.

Mark Lawrence.

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#31366 — [on topic] Re: readline trick needed

Steven D'Aprano wrote:

> I'm working with the readline module, and I'm trying to set a key
> combination to process the current command line by calling a known
> function, *and* enter the command line.
> 
> Something along the lines of:
> 
> * execute function spam() in some context where it can access
>   the current command line as a string
> * enter the command line
> 
> Function spam() may or may not modify the command line.

> (P.S. I'm aware of IPython, I want to get this working in the standard
> CPython interpreter.)

If IPython does what you want why don't you have a look at the source?

Anyway, here's what I came up with (no warranties as it was all trial-and-
error):

$ cat readline_callback.py
import ctypes
import ctypes.util
from ctypes import c_int, c_char_p
import readline
import sys

rlname = ctypes.util.find_library("readline")

# int rl_add_defun (const char *name, rl_command_func_t *function, int key)
# typedef int rl_command_func_t (int, int);
# int rl_done
# char * rl_line_buffer

rl = ctypes.CDLL(rlname)

RL_COMMAND_FUNC = ctypes.CFUNCTYPE(c_int, c_int, c_int)

intercepted_line = None
def lovely_spam(a, b):
    global intercepted_line
    print
    intercepted_line = c_char_p.in_dll(rl, "rl_line_buffer").value
    rl.rl_insert_text("*" + intercepted_line)
    c_int.in_dll(rl, "rl_done").value = 1
    return 0

def control(c):
    return ord(c.upper())-64

rl.rl_add_defun("lovely-spam", RL_COMMAND_FUNC(lovely_spam), control("P"))

#rl.rl_add_defun("lovely-spam", RL_COMMAND_FUNC(lovely_spam), -1)
#readline.parse_and_bind("Control-P: lovely-spam")

$ python -i readline_callback.py 
>>> alpha = 42
>>> alpha
1764

The relevant documentation:
http://cnswww.cns.cwru.edu/php/chet/readline/readline.html
http://docs.python.org/library/ctypes.html

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#31384 — Re: [on topic] Re: readline trick needed

On Tue, 16 Oct 2012 10:30:01 +0200, Peter Otten wrote:

> Steven D'Aprano wrote:
> 
>> I'm working with the readline module, and I'm trying to set a key
>> combination to process the current command line by calling a known
>> function, *and* enter the command line.
>> 
>> Something along the lines of:
>> 
>> * execute function spam() in some context where it can access
>>   the current command line as a string
>> * enter the command line
>> 
>> Function spam() may or may not modify the command line.
> 
>> (P.S. I'm aware of IPython, I want to get this working in the standard
>> CPython interpreter.)
> 
> If IPython does what you want why don't you have a look at the source?

Well, I was hoping for a pure Python solution, rather than having to 
troll through who knows how many thousands of lines of code in a language 
I can barely read.


> Anyway, here's what I came up with (no warranties as it was all
> trial-and- error):
> 
> $ cat readline_callback.py
> import ctypes

Ah, ctypes.

Well, I guess I have some interesting study ahead of me, to make head or 
tail of your solution. Thank you!



-- 
Steven

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#31394 — Re: [on topic] Re: readline trick needed

On 10/16/12 12:27 PM, Steven D'Aprano wrote:
> On Tue, 16 Oct 2012 10:30:01 +0200, Peter Otten wrote:
>
>> Steven D'Aprano wrote:
>>
>>> I'm working with the readline module, and I'm trying to set a key
>>> combination to process the current command line by calling a known
>>> function, *and* enter the command line.
>>>
>>> Something along the lines of:
>>>
>>> * execute function spam() in some context where it can access
>>>    the current command line as a string
>>> * enter the command line
>>>
>>> Function spam() may or may not modify the command line.
>>
>>> (P.S. I'm aware of IPython, I want to get this working in the standard
>>> CPython interpreter.)
>>
>> If IPython does what you want why don't you have a look at the source?
>
> Well, I was hoping for a pure Python solution, rather than having to
> troll through who knows how many thousands of lines of code in a language
> I can barely read.

Are you confusing IPython, the pure Python REPL for CPython, for IronPython, the 
C# implementation of Python?

   https://github.com/ipython/ipython

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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#31396 — Re: [on topic] Re: readline trick needed

On Tue, 16 Oct 2012 13:20:24 +0100, Robert Kern wrote:

> On 10/16/12 12:27 PM, Steven D'Aprano wrote:

>> Well, I was hoping for a pure Python solution, rather than having to
>> troll through who knows how many thousands of lines of code in a
>> language I can barely read.
> 
> Are you confusing IPython, the pure Python REPL for CPython, 

IPython is pure Python?

Well, you learn something new everyday. Or at least I do.

I guess that means that I can look forward to trolling through 250 or so 
Python modules instead of C code :)


Thanks to everyone who replied.


-- 
Steven

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#31406 — Re: [on topic] Re: readline trick needed

On Tue, Oct 16, 2012 at 7:27 AM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Tue, 16 Oct 2012 10:30:01 +0200, Peter Otten wrote:
>
>> Steven D'Aprano wrote:
>>
>>> I'm working with the readline module, and I'm trying to set a key
>>> combination to process the current command line by calling a known
>>> function, *and* enter the command line.
>>>
>>> Something along the lines of:
>>>
>>> * execute function spam() in some context where it can access
>>>   the current command line as a string
>>> * enter the command line
>>>

I'm working on the dictionary now,but I came up with this, which uses
a list as the key, and accepts the params to perform the function:

import subprocess as sub
key_list = ['print_something','espeak']

def print_something(params):
	print "%s" % (params)

def espeak(params):
	sub.call(['espeak','%s' % (params)])

key = raw_input("Please enter key: ")

for line in key_list:
	if str(line) == key:
		params = raw_input("Enter Params: ")
		eval("%s('%s')" % (key,params))


I keep getting the function performed in the dict. I'll figure it out
eventually, I know I've done it before, and it might be a lambda
solution...not sure.

But the above could be refined more, it just uses a list, and key/params.


-- 
Best Regards,
David Hutto
CEO: http://www.hitwebdevelopment.com

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#31407 — [off topic], was Re: [on topic] Re: readline trick needed

Dwight Hutto wrote:

I knew I'd eventually regret putting "on topic" into the subject...

Well done, Dwight. 

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#31412 — Re: [off topic], was Re: [on topic] Re: readline trick needed

On Tue, Oct 16, 2012 at 10:36 AM, Peter Otten <__peter__@web.de> wrote:
> Dwight Hutto wrote:
>
> I knew I'd eventually regret putting "on topic" into the subject...

I didn't write that. If you're referring to OT, it means Off Topic,
and a response would be appreciated. And you can call me David, I go
by my middle name.
>
> Well done, Dwight.
>
> --
> http://mail.python.org/mailman/listinfo/python-list



-- 
Best Regards,
David Hutto
CEO: http://www.hitwebdevelopment.com

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#31369 — Re: [on topic] Re: readline trick needed

In article <k5j5sk$msb$1@ger.gmane.org>, Peter Otten <__peter__@web.de> 
wrote:
> Steven D'Aprano wrote: 
> > I'm working with the readline module, and I'm trying to set a key
> > combination to process the current command line by calling a known
> > function, *and* enter the command line.
[...]
> Anyway, here's what I came up with (no warranties as it was all trial-and-
> error):
[...]

Keep in mind that the Python readline module may be linked to either the 
GPL-licensed GNU readline or the BSD-licensed editline (libedit) library 
(the default on newer OS X systems and probably on *BSD systems) and 
they have different command strings.  Note the warning here:

http://docs.python.org/py3k/library/readline.html

Or it may not be linked with either.

-- 
 Ned Deily,
 nad@acm.org

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#31377 — Re: [on topic] Re: readline trick needed

Ned Deily wrote:

> In article <k5j5sk$msb$1@ger.gmane.org>, Peter Otten <__peter__@web.de>
> wrote:
>> Steven D'Aprano wrote:
>> > I'm working with the readline module, and I'm trying to set a key
>> > combination to process the current command line by calling a known
>> > function, *and* enter the command line.
> [...]
>> Anyway, here's what I came up with (no warranties as it was all
>> trial-and- error):
> [...]
> 
> Keep in mind that the Python readline module may be linked to either the
> GPL-licensed GNU readline or the BSD-licensed editline (libedit) library
> (the default on newer OS X systems and probably on *BSD systems) and
> they have different command strings.  Note the warning here:
> 
> http://docs.python.org/py3k/library/readline.html

I think you are a Mac user. If so, can the snippet I posted be generalised 
to work with libedit?
 
> Or it may not be linked with either.

OK, change "no warranties" to "absolutely no warranties" ;)

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#31432 — Re: [on topic] Re: readline trick needed

In article <k5jcbs$eub$1@ger.gmane.org>, Peter Otten <__peter__@web.de> 
wrote:
> Ned Deily wrote:
> > Keep in mind that the Python readline module may be linked to either the
> > GPL-licensed GNU readline or the BSD-licensed editline (libedit) library
> > (the default on newer OS X systems and probably on *BSD systems) and
> > they have different command strings.  Note the warning here:
> > 
> > http://docs.python.org/py3k/library/readline.html
> 
> I think you are a Mac user. If so, can the snippet I posted be generalised 
> to work with libedit?

Isn't it hairy enough??

Here's how to make tab complete work with both; it gives an idea of the 
libedit commands:

     import rlcompleter
     if 'libedit' in readline.__doc__:
         readline.parse_and_bind("bind ^I rl_complete")
     else:  # GNU readline format
         readline.parse_and_bind("tab: complete")

The documentation of the command syntax is in the .editrc man pages, for 
example:

https://developer.apple.com/library/mac/#documentation/Darwin/Reference/M
anPages/man5/editrc.5.html
 
> > Or it may not be linked with either. 
> OK, change "no warranties" to "absolutely no warranties" ;)

Good idea.

-- 
 Ned Deily,
 nad@acm.org

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