Use of a variable in parent loop

[Terry Reedy]

On 9/26/2020 12:43 AM, Stephane Tougard via Python-list wrote:

[Example of Perl block scoping.]

> ===PYTHON===
> #!/usr/local/bin/python
> if 4 == 4:

if True:  # Only usefel in Python if you might might to switch to False.

>      name = "Stephane"
>      print(name)
>      pass

Noise.  Only 'pass' when there is no other code.

> print("Out {}".format(name))
> ============
> 
> The exact same code in Python works fine, the variable name is used
> outside of the if block even it has been declared inside.

'name' is bound to a object, not declared
The only declarations are 'global' and 'nonlocal'.

Python only creates new scopes for class and function definitions.  At 
least for CPython, comprehensions are implicit function definitions.

> This does not look right to me.

Because you are accustomed to block scoping.

  Can we change this behavior

No.

> or is there any point to keep it this way ?

Aside from not breaking most every existing Python program?  If block 
scoped, one would have to add an otherwise useless fake declaration 
before the block to use the name outside the block.  Python tries to 
avoid boilerplate code.

-- 
Terry Jan Reedy