[on topic] Re: readline trick needed
Peter Otten
__peter__ at web.de
Tue Oct 16 04:30:01 EDT 2012
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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