I have an alternate, non-breaking solution to the scope issue previously discussed on discourse and github . The new potential solution is the following rule to decide whether a variable, x, which is not marked as explicitly local or glogal and which is assigned to in a top-level scope construct is l…

I’m not a fan of what I just proposed, it was just what I understood. I don’t think global for with implicit globals is a good idea because it will leak variable declarations into the containing scope.

[image] StefanKarpinski: Yes, it has to be a purely syntactic criterion. If you see a conditional, you consider all branches; if you see a loop you consider it being executed and not executed (for these purposes, a loop is equivalent to an if without an else ). If there’s any @goto we should pro…

[image] StefanKarpinski: Further hole-poking and counter-examples are welcomed! Can you please clarify for which constructs and contexts this would apply? Eg for, while, try-catch-finally, let, comprehensions, broadcast-fusing, only for the REPL? or all module/baremodule?

are there examples of for or let blocks evaluated in a module scope where we definitely would want the variables in those blocks to be local? Yes, this happens frequently when you copy/paste method bodies to the REPL and wrap them in a let. For example, in a function I can use first as a variable…

[image] jballanc: Forgive me if I’m missing something, but couldn’t we perhaps have an even simpler heuristic: variables in non-function scopes are global when they exist outside of a function scope? This was precisely the solution previously proposed here: [image] Another p…

[image] Tamas_Papp: for , while , try - catch - finally , let , comprehensions, broadcast-fusing, All scope-introducing constructs that occur outside of a function body. only for the REPL? or all module / baremodule ? Both. One of the goals is not to have different behaviors in differen…

[image] StefanKarpinski: One of the goals is not to have different behaviors in different places. :100:

Ok, yeah so I did miss something…apologies! In my defense, it’s been a bit difficult as a bystander to try and follow all the proposed solutions and counter-examples. Glad we have some individuals focusing so much of their attention on this issue. From the multiple issues/threads, it’s obviously som…

[image] tim.holy: For example, in a function I can use first as a variable without conflicting with the function named first ; if first is local to the let , then there is also no conflict and my copy/paste debugging works. So, this has me wondering how much of the trouble around this issue a…

[image] foobar_lv2: Forgive me if I’m wrong, but I thought for and while are syntactic sugar for let and conditional @goto (plus some iterate calls in the case of for ); and if , else , etc are syntactic sugar for conditional @goto . For that reason, the rule needs to work post-lowering and be …

New scope solution

Internals & Design

StefanKarpinski Split this topic October 26, 2018, 12:12pm 65

A post was merged into an existing topic: Side discussion on gotos

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New scope solution

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