Terry J. Reedy <[email protected]> added the comment:
Since 'we' can reopen any closed issue, I will try to answer what I think you
might be asking.
I closed this because of Daniel's suggestion coupled with the Richard
disclaiming further interest and neither Raghuram nor any new responder saying
anything more.
The issue title is a misstatement arising from the OP not noticing how to
change the behavior. Anyone reopening this (or opening a new issue) would need
to change the title to reflect what he thinks should be done. I will not do
that because the naive change proposed in the thread seems unnecessary, while
further investigation suggests that it may be wrong or insufficient.
The original post refers to use_rawinput as a 'module global value'. It is not
that but a cmd.Cmd class data attribute that can be changed either for the
class or an instance. It is one of 9 that might be so changed.
Looking at the patch with #405952 shows that Cmd.__init__ had no parameters and
Cmd.cmdloop always read input with raw_input(), now renamed just input()
(making the attribute name a bit obsolete). The replacement then was something
like
if self.use_rawinput:
try:
line = input(self.prompt)
except EOFError:
line = 'EOF'
else:
sys.stdout.write(self.prompt) # note sys.,
sys.stdout.flush() # not self. here
line = sys.stdin.readline()
if not len(line):
line = 'EOF'
else:
line = line[:-1] # chop \n
The reason for this patch, which *almost* replicates raw_input(), was that
raw_input and/or readline swallowed an exception, whereas the replacement code
does not. I wonder:
1. Does input() still do the same and should it?
2. Is there something about cmd processing that this is the only use of input()
where this exception swallowing is a problem?
3. If so, why not always use the replacement? Speed?
4. I am sort of asking whether this was/is really the right hack.
Someone later added completekey as an initialization parameter (rather than as
a date attribute) and the following code
if self.use_rawinput and self.completekey:
try:
import readline
self.old_completer = readline.get_completer()
readline.set_completer(self.complete)
readline.parse_and_bind(self.completekey+": complete")
except ImportError:
I know nothing about readline and why it (apparently) requires the use of
input(), but the point here is that setting use_rawinput to False disables
completekey. This should be documented but I did not see such.
At the same or later time, someone added stdin and stdout parameters and change
'sys' to 'self' in the first snippet above. Given that these parameters appears
useless when use_rawinput is True, why was use_rawinput not automatically set
to false then? Blunder or subtle reason? Someone who proposes auto-resetting
should try to find the name of the patch and/or commit author and ask.
It seems to me that all the process parameters should be handled uniformly.
Make then all class attributes and let any be changed for instances as keyword
attributes to __init__(). Given the conflict noted above, perhaps raise
ValueError if someone makes contradictory changes.
So, Éric, if your question was academic, I would leave this closed.
If it was not, and you want to reopen, retitle, and assign it to yourself, go
ahead.
----------
_______________________________________
Python tracker <[email protected]>
<http://bugs.python.org/issue2571>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
