[pypy-dev] Paul Fernhout wants edit-and-continue in python
Luke Kenneth Casson Leighton
lkcl at lkcl.net
Mon Apr 2 13:58:09 CEST 2007
integration with leo - http://leo.sf.net - would be a good start.
that would give you the GUI part, and context-sensitive execution.
you _might_ have to do something similar to what gcc currently
do, which is to hook in to eevvvveerryyything via __blahblah__
functions, for memory access eevveryyyything, in the "profiling".
but that shouldn't be too hard (but would result in a performance
hit - oh well, can't have everything).
execution itself (from leo) could be performed via "yield".
ok. you can obtain a list of all variables (global etc.)
that a particular function modifies, right?
so, before you go into any function, right, you record the
in fact, you might be able to record "state" on a per-line
basis (bit extreme i know) and basically have an "undo" stack
yeh. it's very simple. look up how "undo" is implemented,
in editors, and then treat all variables like that.
then, you can keep a record (using Leo) of which lines were
modified, and use that to calculate which bits need JIT
recompilation and how far back the "undo" stack you need to
in _fact_, and this is going to _really_ blow you away, Leo
probably already _has_ an "Undo" capability - and so if you
mentally turn things round, by treating "execute 1 function"
as an "edit" operation under Leo, then you get what you want,
of course, if any variables are "volatile" - e.g. in an OS,
like cleese, then you're shafted - but that's another story.
and, of course, if anything calls out to _non_ python code,
then you're equally shafted.
in both cases, you can simply throw an exception saying "sorry,
you need to run this program from scratch, dude".
you stand a better chance of doing this in pypy than the python
they consider it "impossible", because it's too radical
a rethink, because they have been trapped, by design, in c-code.
p.s. leo is in python, in case you hadn't guessed.
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