Ability to declare a static variable in a procedure, function, or method

[woodnt]

Summary

The ability to declare a variable as static for a proc etc so global variables don't have to be used and thus stored in the BSS segment affecting efficiency. Closures could be used, at the expense of readability code complexity. Since static-type ability is present in C and C++ (and a closure could be implemented behind the scenes in Javascript if that is needed), if would seem not a great hurdle to add to nim-lang.

Description

This is different from using the global pragma, which is to be avoided to keep the variable out of the BSS segment, which is where globals go.

Alternatives

No response

Examples

proc myCounter(): int = 
  static var c = 0 # only initialized once
  c = c + 1
  return c

Backwards Compatibility

No response

Links

No response

[Araq]

I don't understand the difference to the .global pragma.

[nocturn9x]

I don't understand the difference to the .global pragma.

Do static variables in C go in the BSS segment? I don't recall, but I think the semantics around globals vs static locals is different.

[litlighilit]

Do static variables in C go in the BSS segment?

Initialized ones go in DATA segment while Uninitiated go in BBS.

but I think the semantics around globals vs static locals is different.

At least currently, the .global variable without a value assigned is in .bbs and that with a value is in .data.

Though not on purpose, .global does extractly what static does.

And anyway, this's about adding an extra pragma targeting only C like backend.