Tuples -- who needs 'em

[Glenn Andreas]

In article <38ED8EF2.B0835BE1 at acm.org>, "Robert W. Cunningham" 
<rcunning at acm.org> wrote:

> Greg Ewing wrote:
> 
> > Unfortunately, Python *does* need 1-tuples. If
> > only ASCII had more kinds of brackets, Guido might
> > have chosen differently. Maybe if Python 3000 uses
> > Unicode for source files...
> 
> Well, if they can be syntactically disambiguated from Python relational
> comparison operators, "<" and ">" can be used as "brokets".
> 

Funny, I was thinking the exact same thing.  Other than needing some 
extra spaces, it should work (after all, C++ uses them as well).  
However, depending on the details of the parser (and it's been way too 
long since I've brushed up on parser technology), you might have 
problems with:

   x = < a, a > b >  # (a,a>b) in old syntax

At the very least, this visually is jarring and you need to mentally 
"reparse" when you get to the second ">".  Another alternative is to 
switch to multi-character brackets, perhaps:

   x = (* a, b *)

or:

   x = <| a, b |>

With two characters, there could be hundreds of possible "bracket" 
pairs.  Unfortunately, that makes your code look like it has been 
infested with "smileys".  I seem to remember that some other languages 
using them though (besides old Pascal style comments, that is).