Hi,
The long story short:
* EXCEPTION_LEX_NOT_FOUND is not picked up correctly from the include file
* The return continuation of the exception does not save registers,
since $P1 (mapped to P16 by imcc) is messed up by $P2 (also mapped to
P16).
* I would really like the name of the missing lexical in a field
"_lexical" of the exception hash.
What am I missing?
The short story long:
I am experimenting with find_lex and the exception is throws as of
yesterday (LEX_NOT_FOUND). I use the test program below. When I run
this, the exception is thrown but the handler complains that the
exception object is of the wrong type.
$ ../parrot-head/parrot/parrot test8.pir
Exception object is of the wrong type!
When I zap the EXCEPTION_LEX_NOT_FOUND to the fixed constant 4 it works,
but then I get:
$ ../parrot-head/parrot/parrot test8.pir
Hello from handler!, message is Lexical 'n' not found
get_string() not implemented in class 'Continuation'
which is caused by the "print $P1" in sub "_print_n". It turns out that
both $P1 in "_print_n" and "$P2" in "_handler" map to P16. Thus the
return invocation from the exception handler does not restore the
registers. I thought (hoped, prayed) it would. Am I missing something?
Furthermore, I would really (really) like the name of the lexical that
caused the exception as a field in the exception PMC (e.g. "_lexical").
++Jos.nl
------------------------------------------------------------------------
.include "../parrot-head/parrot/runtime/parrot/include/except_types.pasm"
.sub _main
new_pad 0
call _print_n
end
.end
.sub _print_n
saveall
newsub $P2, .Exception_Handler, _handler
set_eh $P2
find_lex $P1, "n"
clear_eh
defined $I0,$P1
eq $I0,0,_noprint
print $P1
print "\n"
_noprint:
restoreall
ret
.end
.sub _handler
set $I0, P5["_type"]
ne $I0, EXCEPTION_LEX_NOT_FOUND, _wrongtype
print "Hello from handler!, message is "
set $S0, P5["_message"]
print $S0
print "\n"
set $P2, P5["_invoke_cc"] # the return continuation
invoke $P2
_wrongtype:
print "Exception object is of the wrong type!\n"
end
.end
------------------------------------------------------------------------
--
ek is so lug jy vlieg deur my
sonder jou is ek sonder patroon
"Breyten Breytenbach"
