single-line terinary operators considered harmful

Clark C. Evans cce at clarkevans.com
Wed Mar 5 03:57:08 CET 2003


On Wed, Mar 05, 2003 at 02:14:06AM +0000, Dennis Reinhardt wrote:
| The weakness is that Python has a "dangling else" ambiguity which requires
| indentation to disambiguate (i.e. the if-else must occupy two lines
| minimum).

Why is this a weakness?  I like indentation.  I use Python exactly
beacuse it uses indentation to show me structure.  The biggest problem
I have with all of the 'terinary' options is that they are 
single-line solutions.

The only solution that the terinary operator needs to solve
is a way to provide for conditional logic within an expression
intead of forcing the programmer to use statements.

After the select/case option presented previously, my second
best option would be something like...

   var = (if 1 == x: 'yes'
          else: 'no')

Where the 'else' must be in the same column as the 
corresponding if.

Getting it to fit on a single line is just an unnecessary
distraction, and, IMHO, one that is bogging down the whole 
discussion down... and preventing a good mechanism to 
express conditional logic within an expression.
 
Grins,

Clark





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