[PATCH 0/4] Speed improvement in fetch/clone

[Martin Pool]

On 19 Jan 2006, Jan Hudec <bulb at ucw.cz> wrote:
> On Thu, Jan 19, 2006 at 01:56:32 -0800, Robey Pointer wrote:
> > 
> > On 18 Jan 2006, at 13:52, Goffredo Baroncelli wrote:
> > 
> > >+        pb = pb and pb or bzrlib.ui.ui_factory.progress_bar()
> > 
> > I wanna give a -1 to this line.  This construction (x and y or z) and  
> > its pitfalls is actually the reason the ternary operator was added to  
> > python 2.5 and even after long discussions about what it means, I  
> > *still* find it confusing.
> > 
> > A 4-line if/else will cost you screen real estate but win you the  
> > love of your fellow man. :)
> 
> Besides it will only be a 2-line if. The expression is screwed, but IMHO
> not for using and+or for ternary (I am used to that from other
> languages (that do have ternary, by the way)), but for:
> 1) Assigning what is already assigned.
> 2) Containing redundant terms -- (pb and pb) == pb

Right.

> In languages that have it I'd suggest pb or= ....progress_bar(), but
> python only supportst augmented assignment for arithmetic operators.

I'm just curious, what language has "assign if the LHS is null"?  Perl6?

-- 
Martin
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