JSD: Stepping by line

Currently, JSD gets called (InterruptHook) from SpiderMonkey for each 
instruction executed in SpiderMonkey's compiled bytecode. That's not 
going to change, but what people have shown concern about is that JSD 
calls into its registered interrupt hook (usually JS) for each of these.

People claim that costs time.

It is interesting because it isn't just a trivial fix; Venkman, for 
example, actually has two quite unlinked ways of counting lines (normal, 
and pretty print [PP]). Of course, since PP is a specific feature of 
JSD's exposed interfaces, one possibility to help is to give JSD a new 
3-way setting:
  - oldskool (call for each instruction in SpiderMonkey)
  - by line, normal (call/unique line by the normal PC->line map)
  - by line, PP (call/unique line by the PP PC->line map)

Thoughts?

-- 
James Ross <[email protected]>
Bored ChatZilla Developer