[Python-bugs-list] [ python-Bugs-587239 ] python-mode and nested indents

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Bugs item #587239, was opened at 2002-07-26 16:56
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Category: Demos and Tools
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Andrew Koenig (arkoenig)
>Assigned to: Barry A. Warsaw (bwarsaw)
Summary: python-mode and nested indents

Initial Comment:
Using Python-mode 4.6 and GNU emacs 21.2.2, I enter the
following:

if x < 0:
    for i in range(100):
        print i
else:
    print "x is negative"

If I now put the cursor on the "else:" line and hit
tab, it erroneously changes the indentation to line the
"else" up with the "for" above it.


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>Comment By: Tim Peters (tim_one)
Date: 2002-07-26 18:05

Message:
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user_id=31435

I agree that the second one (elif) may be considered a 
bug.  Afraid I can't agree aboiut the first reason, though:  of 
course hitting tab in pymode can change the meaning.  
When you've got

if whatever:
->x
y

and hit tab when on the line containing y, it assumes you're 
hitting tab for a reason, not just to make trouble <wink>.

I believe there's a discussion about this in the long form of 
the pymode help.  Since pymod can't *know* the block 
structure you intend, it does its best to guess, and hitting 
a "guess the block structure I intended" key is taken as 
meaning, for a start, that the block structure on the current 
line isn't what you intended (else why would have hit the 
key?  as a Python programmer, you should already know 
this isn't C mode <wink>).

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Comment By: Andrew Koenig (arkoenig)
Date: 2002-07-26 17:49

Message:
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Frankly, I hadn't thought of that possibility!

However, I still consider the behavior a bug, for two
reasons:  (1) I can type something that's syntactically
valid, hit tab, and have it change the meaning of what I
typed, and (2) It changes the indentation in the same way if
I say "elif:" instead of "else:", even though that change is
not syntactically valid.  That is (using -> to indicate a
tab):

if x < 0:
->for i in range(100):
->->print i
elif x > 0:
->print x

Again, hitting tab on the "elif" line will indent the "elif"
to line up with the "for", even though the result is
syntactically invalid.


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Comment By: Tim Peters (tim_one)
Date: 2002-07-26 17:14

Message:
Logged In: YES 
user_id=31435

Andrew, why is that erroneous?  Loops in Python have 
(optional) "else:" clauses too.  There's no way for pymode to 
guess whether you intended the else to go with the if or the 
for.  I expect it looks backward for the closest-preceding 
construct the else-statement could "belong to", and finds 
the for-loop first.

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https://sourceforge.net/tracker/?func=detail&atid=105470&aid=587239&group_id=5470