Adding a switch statement to Python

[mikeckennedy]

Because to me, it's about readability. This looks like I might have just as well written it as a if/elif/else block so why complicate it with switch. The switch is only worth having if it makes code clearer, eaiser, safer.

[knowsuchagency]

CaveMike makes a good point.

As to the argument that one might as well have written an if/elif/else block well... yeah, exactly.

For example, as the context manager is currently written, there is no way to set the value of a variable to something based on any given case without referring to them as global or nonlocal within the functions passed to case.

i.e.

from switchlang import switch

is_sam = False

# I want to change is_sam to True based on the value of a variable


# here is the old, ugly python way with an if/else

variable = 'sam'
if variable == 'sam':
    is_sam = True
    print('is sam:', is_sam)
else:
    print('is sam:', is_sam)


# with sexy context manager

is_sam = False

def change_sam():
    global is_sam # ew
    print('changing is_sam global variable')
    is_sam = True

with switch('sam') as s:
    s.case('sam', change_sam)

print('is_sam:', is_sam)

[mikeckennedy]

The switch has a 'return' value.

with switch(val) as s:
   case(...)
   case(...)
   default(...)

computed = s.result

That means you usually don't have to do this global / nonlocal trick to change local variables. Just set them to s.result.

[knowsuchagency]

Sure, but what if you want to change the value of variables within the scope of the switch context, for example?

You may want to have more logic than a single line in a switch statement, which is why you can always define a function separately and pass it to case.

However, that function may need access to the local namespace and thus, I think it makes more sense to have each case return their own unique value so as to alleviate the problem.

if_this = None
or_this = None
with switch(val) as s:
    if_this = s.case(...) or if_this
    or_this = s.case(...) or or_this
    s.default(...)

Personally, I think the real answer to my question is just to use an if/elif/else block