plans for gcobol 16

[Jose E. Marchesi]

Hi James.

> 1.  "National" support.  COBOL programs define the runtime encoding and
> collation of each string (sometimes implicitly).  COBOL defines two
> encodings: "alphanumeric" and "national".  Every alphanumeric (and
> national) variable and literal has a defined runtime encoding that is
> distinct from the compile-time and runtime locale, and from the
> encoding of the source code.  This means
>
> 	MOVE 'foo' TO FOO.
>
> may involve iconv(3) and 
>
> 	IF 'foo' = FOO
>
> is defined as true/false depending on the *characters* represented, not
> their encoding.  That 'foo' could be CP1140 (single-byte EBCDIC) and
> FOO could be UTF-16.  
>
> Cauldron Alert:  Who was I talking to?  Unicode equality and inequality
> require library support.  Some wise person in Porto agreed that 1) GCC
> was unlikely to want to add ICU as a dependency and 2) a limited amount
> of Unicode evaluation is available in (IIRC) gnulib, which might be
> adapted to libiberty, and might serve the purpose.  Problem is, I don't
> remember and didn't take notes.  If that conversation sounds familiar,
> please ping me.  
>
> Conversion is a solved problem.  Comparison is not.  And, no, afaik the
> C and C++ libraries are insufficient.  Anything that relies on the
> environment is begging for trouble.

For the Algol 68 Unicode needs I am using a small set of functions that
I hand-adapted from the libunistring gnulib module.

The functions needed at compile-time are in

  https://forge.sourceware.org/gcc/gcc-a68/src/branch/a68/gcc/algol68/a68-unistr.c

The functions needed at run-time are in:

  https://forge.sourceware.org/gcc/gcc-a68/src/branch/a68/libga68/ga68-unistr.c

If libunistring fulfills your comparison needs (see manual at [1]) then
perhaps you could use a similar strategy.  It would be good to avoid
duplicating that code though.

(Note that the reason I am using a customized version is that the
 elements in my strings may be stored with a stride > 1 so I modified
 the libunistring functions to account for that.  Not sure if Bruno
 would welcome the addition of an interface where you can specify
 strides, but if so, I will gladly submit a patch to libunistring.)

[1] https://www.gnu.org/software/libunistring/manual/libunistring.html