[Python-3000] Stackable Blocks

[Nick Coghlan]

Crutcher Dunnavant wrote:
> Having been shot down so hard on my request to bring for loops into
> symetry with list comprehensions, I have a new proposal - stackable
> blocks.
> 
> This is a very _small_ amount of syntax sugar, the basic idea is that
> any block headers can be stacked on the same line. This changes no
> semantics, nor does it change ordering, or add new keywords, it just
> changes a tiny bit of the grammar for whitespace/block parsing.

What's wrong with a bit of vertical whitespace? If your code blocks are 
cascading to the right of screen, it's a sign that something needs to be 
pulled out into a separate function or generator.

> can be spelled like this.
> 
> for file in open_files: if file.readable():
>   ...

def readable_files(files):
     for f in files:
         if f.readable():
             yield f

for f in readable_files(open_files):
     ...

> can be spelled:
> 
> for i in range(10): for j in range(20): if i != j:
>   ...

def cartesian(x_coords, y_coords):
     for x in x_coords:
         for y in y_coords:
             yield x, y

for i, j in cartesian(range(10), range(20)):
     if i != j:
         ...

> can be this:
> 
> for line in open(file): if line.strip():
>   ...

def stripped(f):
     for line in f:
         yield line.strip()

for line in stripped(f):
     ...

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
---------------------------------------------------------------
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