[Glass] [3.4.0] Strange behaviour with indices ...

Johan Brichau via Glass glass at lists.gemtalksystems.com
Tue Mar 27 10:00:38 PDT 2018


Skimming this thread… we uncovered that problem as well in our migration from GS2.4 to GS 3.2 (or later). 
We started seeing strange differences and only recently unlocked the issue:

Even when using the locale en_US_POSIX, there seem to be cases where Strings are not compared by comparing their integer code point values. Example Strings:
string1 := String with: (Character codePoint: 16r00E9).
string2 := String with: (Character codePoint: 16r0065) with: (Character codePoint: 16r0301).

Even with the default IcuLocale set to en_US_POSIX, these strings are #=-equal:
string1 = string2 "=> true"
While this is not GemStone2-compatible behavior, it's not that bad for the Strings to be equal according to #=, as they are in fact canonically equivalent. However, the Strings do not have the same #hash:
string1 hash = string2 hash "=> false”

I’m primarily concerned with places we are using dictionaries with strings as keys and when we are upgrading from GS2.4 to GS3.2 (or later).


> On 20 Mar 2018, at 10:17, monty via Glass <glass at lists.gemtalksystems.com> wrote:
> Dale, you're busy, but did you read the whole String>>#= thread? This:
> | one two |
> one := 'Köln'.
> two :=  String with: $K with: $o with: 16r308 asCharacter with: $l with: $n.
> one = two
> 	and: [one hash ~= two hash]
> is absolutely a bug, not just a surprise. To be consistent with #=, String>>#hash must normalize (with UCI) its string before computing its hash.
> (IMO #=, #<=, etc doing implicit normalization before comparing was a mistake. Either the Java/C# way of making the user manually normalize the strings before comparing or the Perl6 way of storing strings internally in a pre-normalized form would have been more intuitive and consistent. I assume it's too late to change now.)
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