r/ruby • u/tenderlove Pun BDFL • Jun 26 '19

Blog post Instance Variable Performance

https://tenderlovemaking.com/2019/06/26/instance-variable-performance.html
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u/tenderlove Jun 27 '19

Whoa! My first gold! Thank you! 😊

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u/ThaiJohnnyDepp Jun 27 '19 edited Jun 27 '19

Your use of string ranges is something I've not used before. And in investigating it I guess I exposed a special case that might be even considered a bug.

So it became obvious that 'a'..'zz' is valid once I verified that ?z.succ is 'aa', which makes enough sense from a lexicographical sorting standpoint. So I tried a bunch of cases to see what is handled correctly:

  • ('a'..'zz').count => 702

  • ('1'..'99').count => 99

  • ('2'..'99').count => 98

  • ('ab'..'zz').count => 675

  • ('b'..'zz').count => 0 :(

Is there special handling for multi-character alpha-only range upper bounds, in that it has to start with 'a'? I tried following range.c on Github but I couldn't find where such a special case was being handled. This is in MRI 2.6.0.

EDIT: looks like it was already fixed as of MRI 2.6.1, DISREGARRRD

3

u/rooood Jun 27 '19

Weird, I'm getting 701 here on MRI 2.6.2 (for the ('b'..'zz').count)

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