1y ago

What are some pros and cons of a `scope` keyword?

In something like C++ you could create a scope like so:

cpp

    
{
    // Do something neat here
}

I was wondering about having or maybe even requiring a scope keyword, which might look like this:

cpp

    
scope
{
    // Do something neat here
}

This seems even more relevant in an indentation sensitive language like python:

py

    
scope:
    pass

Interested to hear any opinions, TIA.

7 comments

A scope is already implied by brackets. For example, a namespace, class, method, if block are also scopes.
So I don't really see why you'd want an explicit scope keyword inside methods, when all other scopes are implied... That just creates an inconsistency with the other implied scopes
Nim, which is indentation-based, has a block keyword.

block: echo "something"
I dislike it - every block creating scope is reinforced by the lack of a keyword. Not all languages allow a blank scope block but those that have scope should...
In terms of python, welp, they made their own bed by making white space syntax significant. It was a terrible decision and would require a custom solution... maybe they could let you just arbitrarily indent an extra time?
What's the intention and use case for this?
Only for empty, unlabeled, untyped scopes? Or would I write

function a() scope {}
Is it necessary for scope-ending cleanup of resources? If so, I would consider whether there are not better solutions for those.
Is it for code structuring? I would also consider what use a scope keyword has then, and what the alternatives are.
I don't see how adding a scope label helps with anything.
- To be honest, the only use case I really thought of was something like unlocking a mutex at the end of a scope or maybe a file.
  
  In that case managed languages like python and java combine that functionality with try blocks. This is generally called try with resources.
  C# has the using keyword that just uses local scope.
  The commonality between them is declaring which resource is managed, not just everything is a scope. Imagine you wanted to manage one resource and return another.

7 comments