Re: PATCH: provide %c and %u8c formatting in pickle printf()

[Jose E. Marchesi]

    > I just realized that if the last line of the dump is incomplete then the
    > ascii appears displaced.  Example:
    >
    > (poke) dump :from strtab.sh_offset :size strtab.sh_size
    > 76543210  0011 2233 4455 6677 8899 aabb ccdd eeff  0123456789ABCDEF
    > 000001b0: 002e 7379 6d74 6162 002e 7374 7274 6162  ..symtab..strtab
    > 000001c0: 002e 7368 7374 7274 6162 002e 7465 7874  ..shstrtab..text
    > 000001d0: 002e 6461 7461 002e 6273 7300 2e63 6f6d  ..data..bss..com
    > 000001e0: 6d65 6e74 002e 6e6f 7465 2e47 4e55 2d73  ment..note.GNU-s
    > 000001f0: 7461 636b 002e 7265 6c61 2e65 685f 6672  tack..rela.eh_fr
    > 00000200: 616d 6500  ame.
    > (poke)
    
    Also, if we reach end-of-file, the exception thrown will stop the hex
    output and never reach the ASCII printing.
    Is there a predicate we can test for EOF in the loop ?

Hmm, you could test for EOF with something like this:

defun eof = (offset<uint<64>,B> offset) int:
{
  try
    uint<8> @ offset;
  catch if E_eof
  {
    return 1;
  }
  return 0;
}

But that seems a bit overkill?  An alternative, probably more natural,
is to catch EOF around the loop, do the right thing, then re-raise:

try
  THE_LOOP_INCLUDING_draw_ascii_line;
catch if E_eof
{
  draw_ascii_line;
  raise E_eof;
}

I wonder, maybe we would benefit from some extra language constructions
for situations like this?

For the record, there are three supported forms of try-catch in Poke:

try STMT catch COMPOUND_STMT
  catches all exceptions.
try STMT catch if EXPRESSION COMPOUND_STMT
  catches exceptions with code EXPRESSION
try STMT catch (Exception FORMAL) COMPOUND_STMT
  catches all exceptions, FORMAL contains the exception.  Exception is
  defined to be of type int<32>.