The last (and never done correctly) relict of old calling conventions...
Technically an excpetion is kind of an object with some info (TODO) and
the exception handler is a (limited) continuation:
pmclass Exception_Handler extends Continuation ... # see classes/
Throwing an exception is calling an exception handler and delivering
results. This is the same as invoking a continuation. See e.g.
t/op/calling_48.pir or t/op/lexicals_29.pir.
Which means that we need:
catch_label:
get_results "(...)", Pexcept, Smessage, ... # whatever
or in PIR speak, the left hand side of a sub call;
(ex, mess, ...) = catch_label # the RHS is just a label or the
handler ...
(the left side - the results part - is that where continuations are
branching to - strange isn't it?)
And the opcode
push_eh catch_label
is creating the Exception_handler with the 'get_results' in it's
context, so that it can deliver results.
Just a brain dump before I forget it ;-)
Detailed syntax bits welcome ...
leo
