Hi Daniel,
>Hi Thorsten, apologies for the delay.
don’t worry about that ;)
>> >Interesting! So POSIX assumes ASCII, to a certain extent.
>>
>> Yes, it does. I think EBCDIC as charset is actually nonconformant, but
>> it probably pays off to stay close nevertheless. (This is actually
>> about the POSIX/'C' locale; other locales can pretty much do whatever
>> they want.)
>
>Ah, okay, C locale; that makes sense. I did imagine POSIX was largely
>agnostic about the character set.
It is, but it prescribes that certain operations in the POSIX locale
use ASCII ordering for codepoints no matter which bytes they actually
have in the internal representation.
>> >Even if you really do need a table, you could populate it on startup
>> >using these.
>>
>> Indeed… but we have the compile-time translated characters all over
>> the source (I think we agreed earlier that not supporting changing it
>> at runtime was okay).
>
>Oh, so you mean like if(c=='[') and such? That is certainly reasonable.
>The program would be tied to the compile-time codepage no worse than
>most other programs.
Right. So either something like -DMKSH_EBCDIC_CP=1047 or limiting
EBCDIC support to precisely one codepage.
>(If you could do everything in terms of character literals, without
>depending on constructs like if(c>='A'&&c<='Z'), your code would be
>pretty much EBCDIC-proof.)
Yesss… but…
① not all characters are in every codepage, and
② I need strictly monotonous ordering for all 256 possible octets
for e.g. sorting strings in some cases and for [a-z] ranges
>> I hope to be able to get back to that offer eventually. Glad to know
>> you’re still interested after two years.
>
>Mainframes are not a platform for the impatient... at least not if one
>has to deal with IBM ^_^
Oh… I see. My condolences then ;-)
>> main() { printf("%02X\n", '\n'); return 0; }
>>
>> Out of curiosity, what does that print on your systems, 15 or 25?
> $ ./test
> 15
OK, I can live with that, so I just need to swap the conversion
tables I got (which map 15 to NEL and 25 to LF).
> #pragma convert("ISO8859-1")
[…]
>That may or may not be useful. Of course, the pragma would need to be
Interesting, but I can’t think of where that would be useful
at the moment. But good to know.
Hmm. Can this be used to construct the table?
Something like running this at configure time:
main() {
int i = 1;
printf("#pragma convert(\"ISO8859-1\")\n");
printf("static const unsigned char map[] = \"");
while (i <= 255)
printf("%c", i++);
printf("\";\n");
}
And then feed its output into the compiling, and have
some code generating the reverse map like:
i = 0;
while (i < 255)
revmap[map[i]] = i + 1;
But this reeks of fragility compared with supporting
a known-good hand-edited set of codepages.
(Not to say we can’t do this manually once in order to
actually _get_ those mappings.)
>> Also, what line endings do the auto-converted source files, such
>> as dot.mkshrc, have?
>
> $ head -2 dot.mkshrc
> # $Id$
> # $MirOS: src/bin/mksh/dot.mkshrc,v 1.101 2015/07/18 23:03:24 tg Exp $
>
> $ head -2 dot.mkshrc | od -t x1
> 0000000000 7B 40 5B C9 84 5B 15 7B 40 5B D4 89 99 D6 E2
> 7A
^
OK, it matches the above. That’s all I needed to know, thanks
for confirming this.
>(Yes, binary files do get messed up :-] On z/OS-native filesystems,
>there is a per-file type flag that enables or disables encoding auto-
>conversion. For NFS mounts, you have to mount it as either "binary" or
>"text." The mksh source tree above is on the latter sort of mount.)
Yeah, I remembered something like that from the eMail thread.
That’s fine, we can work with that.
>Let me know if I can help any more!
Okay, sure, thanks. I must admit I’m not actively working on
this still but I’m considering making a separate branch on which
we can try things until they work, then merge it back.
But first, the character class changes themselves. That turned
out to be quite a bit more effort than I had estimated and will
keep me busy for another longish hacking session. Ugh. Oh well.
But on the plus side, this will make support much nicer as *all*
constructs like “(c >= '0' && c <= '9')” will go away and even
the OS/2 TEXTMODE line endings (where CR+LF is also supported)
need less cpp hackery.
Goodnight,
//mirabilos, who had a loooong day working for a nonprofit
--
<ch> you introduced a merge commit │<mika> % g rebase -i HEAD^^
<mika> sorry, no idea and rebasing just fscked │<mika> Segmentation
<ch> should have cloned into a clean repo │ fault (core dumped)
<ch> if I rebase that now, it's really ugh │<mika:#grml> wuahhhhhh
