Would be nice if Mac has finally fixed it.

On Wednesday, March 23, 2022, Eric Iverson <[email protected]> wrote:

> I don’t think think this is a bug in j and don’t think it is an easy fix.
> Probably better things to work on.
>
> On Tuesday, March 22, 2022, bill lam <[email protected]> wrote:
>
>> This is a bug in J.  J should follow MacOS file system name normalization
>> rule. I'll take a look.
>>
>>
>> On Wed, 23 Mar 2022 at 11:01 AM Eric Iverson <[email protected]>
>> wrote:
>>
>> > Not sure. And not sure I want to know.
>> >
>> > But to continue the example:
>> >    fread c NB. fails on macos as the system has the decomposed form as
>> the
>> > name it looks for
>> >    fread d
>> > abc
>> >
>> >
>> > On Tue, Mar 22, 2022 at 9:39 PM Elijah Stone <[email protected]>
>> wrote:
>> >
>> > > I wonder what happens when you create two files with distinct names,
>> and
>> > > then unicode changes such that they are the same when
>> > > normalised/casefolded/..
>> > >
>> > > Probably nothing good.
>> > >
>> > > On Tue, 22 Mar 2022, Eric Iverson wrote:
>> > >
>> > > > My favorite unicode story is from macos filenames.
>> > > >
>> > > > They decompose filenames and only track the decomposed form (letter
>> > > > separate from the overstrike).
>> > > >
>> > > > The following accented chars look the same, but have different
>> values.
>> > > >
>> > > >   c=: 195 164{a. NB. composed
>> > > >   c
>> > > > ä
>> > > >   d=: 97 204 136{a. NB. decomposed
>> > > >   d
>> > > > ä
>> > > >   c-:d
>> > > > 0
>> > > >   'abc'fwrite c
>> > > >   fread c NB. fails on macos as the system has the decomposed form
>> as
>> > the
>> > > > name it looks for
>> > > >
>> > > > Torvald has a wonderful rant about this that is a fun read.
>> > > >
>> > > > On Tue, Mar 22, 2022 at 7:02 PM Raul Miller <[email protected]>
>> > > wrote:
>> > > >
>> > > >> I ran into a situation, today (dealing with files), where most of
>> the
>> > > >> files were utf-8 encoded but some represented the latin-1 "code
>> plane"
>> > > >> with 8 bit characters.
>> > > >>
>> > > >> To cope with this issue, I coded up a mechanism to test whether the
>> > > >> file contained only valid utf-8 sequences, and used {{ ": 10 u: y
>> }}
>> > > >> for the files which failed this test.
>> > > >>
>> > > >> In other words:
>> > > >>
>> > > >> cclass=: (i.9) (48+i.9)} 256#9
>> > > >> cstates=: 0 10#:10* ".;._2{{)n
>> > > >>   0    7.3  2    3    4    5    6    7.3  7.3  7.1 NB. 0: start
>> char
>> > > >> sequence
>> > > >>   0    7.3  2    3    4    5    6    7.3  7.3  7.1 NB. 1: finish
>> char
>> > > >> sequence, start next
>> > > >>   7.3  1    7.3  7.3  7.3  7.3  7.3  7.3  7.3  7.3 NB. 2: need one
>> > > >> more character
>> > > >>   7.3  2    7.3  7.3  7.3  7.3  7.3  7.3  7.3  7.3 NB. 3: need two
>> > > >> more characters
>> > > >>   7.3  3    7.3  7.3  7.3  7.3  7.3  7.3  7.3  7.3 NB. 4: need
>> three
>> > > >> more characters
>> > > >>   7.3  4    7.3  7.3  7.3  7.3  7.3  7.3  7.3  7.3 NB. 5: need four
>> > > >> more characters
>> > > >>   7.3  5    7.3  7.3  7.3  7.3  7.3  7.3  7.3  7.3 NB. 6: need five
>> > > >> more characters
>> > > >>   7.3  7.3  7.3  7.3  7.3  7.3  7.3  7.3  7.3  7.2 NB. 7: end
>> > > >> }}
>> > > >>
>> > > >> utf8lenb=: <:2#.>1 #each~1+i.8
>> > > >> utf8ok=: {{
>> > > >>   try.
>> > > >>     (1;cstates;cclass) ;: '.',~'012345678_'{~ utf8lenb I. 3 u: y
>> > > >>     1
>> > > >>   catch.
>> > > >>     0
>> > > >>   end.
>> > > >> }}
>> > > >>
>> > > >> NB. most content is utf-8 -- assume non-utf-8 sequences are
>> > > ascii+latin-1
>> > > >> latin2utf8=: {{
>> > > >>   if.utf8ok y do. y else. ":10 u: y end.
>> > > >> }}
>> > > >>
>> > > >> I don't know if this approach would be useful to anyone else here,
>> > > >> but... just in case...
>> > > >>
>> > > >> FYI,
>> > > >>
>> > > >> --
>> > > >> Raul
>> > > >> ------------------------------------------------------------
>> ----------
>> > > >> For information about J forums see
>> > http://www.jsoftware.com/forums.htm
>> > > >>
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>
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