I see that the Julia community are currently debating on the new scope rules in v1.0, in an attempt to return to the deprecated soft/hard local scopes in v0.6. In my opinion, neither solution is ideal. Here, let me give my thoughts from a teacher and data scientist’s perspective. In the following, I…

[image] Wenjie: the Julia community are currently debating on the new scope rules in v1.0, in an attempt to return to the deprecated soft/hard local scopes in v0.6 If you are talking about RFC: bring back v0.6 scope rules in the REPL …

I see you worry particularly about the performance and the variable locality inference. Let me analyze it in real-life scenarios and show you that your worries will not happen. Performance Let us consider the following loop s = 0 for i in 1:9 temp = i*i # intend to be local s += temp #…

Then how about making an overhaul in v2.0?

I think that will be decided when 2.0 is coming up based on a cost/benefit analysis. My understanding is that the benefit has to be really large to make breaking changes to things you cannot simply deprecate, which includes scoping rules. FWIW, I hope that scoping will remain unchanged from now on;…

I’m increasingly convinced that the key source of insatisfaction about the current rules is that they differ from Python, so they trouble: (a) people whose programming habits are tied to Python workflows (or similar languages in this regard), and (b) teachers whose syllabus is adapted to Python’s ru…

[image] heliosdrm: “are Python scoping rules acceptable for Julia?” , and development decisions would be simpler to make. You may find this relevant: [image] New scope solution Internals & Design I want to underline this. There are a lot of people here talking abou…

In short Python “sovles” this issue by loops not introducing scope. They don’t introduce scope anywhere, however: not just in global scope but also in functions. This makes loops totally different in scope behavior from comprehensions and introduces its own host of controversial scope problems which…

[image] StefanKarpinski: They don’t introduce scope anywhere, however: not just in global scope but also in functions. As much as I appreciate scoped loops, I’m curious what the practical issues are without them. Isn’t it just when reusing variable names in two ways inside a function which …

What do you want this to do?: fns = [(x = i^2; ()->x) for i = 1:10] # later x = 123 # later still for f in fns println(f()) end Options: Print 1, 4, 9, 25, 36, etc. Print 123 ten times.

1, obviously. Is it bad to have new scope just for comprehensions?

Remove the soft scope altogether and make it global

Internals & Design

Tamas_Papp January 14, 2020, 10:26am 8

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Remove the soft scope altogether and make it global

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