lua_Chunkreader: tracking line numbers

[Juergen Fuhrmann <fuhrmann@...>]

Hi, 

Sorry for posting twice, but this came into my mind just after sending
the previous one:

How line numbers are handeled by lua_load and the chunk reader ?

Here a  (fictive) example  in ldf, similar  things could be  done with
xml.

-----------
$ldf{version={1,0}}
$x=DArray{nrow=3 ncol=5, encoding=base64} 
AAAAvrBAAAAAAAC/sEAAAAAAAMCwQAAAAAAAwbBAAAAAAADCsEAAAAAAAMOwQAAAAAAAxLBA
AAAAAADFsEAAAAAAAMawQAAAAAAAx7BAAAAAAADIsEAAAAAAAMmwQAAAAAAAyrBAAAAAAADL
AAAAwM4SU0EAAAAAzxJTQQAAAEDPElNBAAAAgM8SU0EAAADAzxJTQQ==
$
for i=1,getn(x)  do  
    print(i,x[i]} 
    end

-----------

If Lua  encounters the error  in line 8  of the file, there  are three
possibilities  for the line  number in  the error  message of  the Lua
parser:

a) it is indeed 8  - as one would like to have it in order to debug
  the whole document
b) it is 2, and we possibly could say afterwards:
   "error detected in Lua chunk started at line 7"
c) it is 1 because a chunk is handeled like a buffer.

If there is no way to track  a line number by some measures in the Lua
API,  I don't see  how one  could implement  (a).  

In the lua_dolines  patch, for this purpose, I  just added int *lineno
as a  parameter to the equivalent  of lua_load(). I had  to change not
more than 10  lines of code in  Lua-4.0.1 to get this to  work (IMHO a
sign of sound quality of the code!)

Of course there might be better solutions in the API.

just my EUR 0.02

Juergen