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[REBOL] Words, Bindings and Contexts. (7) Re:(2)

From: lmecir:geocities at: 26-Jul-2000 22:36

> HI Ladislav > > Very cool! Use of simulated behavior (implemented in REBOL) is
a concise
> and precise way of expressing one's thoughts about the workings
> functions. I find it much more informative than lengthy
attempts to
> describe in ordinary language how functions work. > > I have followed your Words, Bindings, and Contexts posts with
> interest. I have learned a lot from your discussions and hope
to see more.
> Just a couple of quick questions: > > Can you say more about Dangerous Contexts? For instance: > >> f: func [x][return x] > >> first :f > == [x] > >> type? first first :f > == word! > >>value? first first :f ;REBOL crashes on any attempt to
examine the
> words in first :f > > Isn't this just a bug in REBOL? Why does it not return an error
instead of
> crash? > > How about a modifying to sim-func to allow handling of /local
> refinements? Then it would be a more complete model of func. > > Thank you again for sharing this excellent material. > > -Larry >
1) I think, that every Rebol Context becomes Dangerous after being Garbage Collected while still accessible, ie. Dangerous Contexts may be just "Ghost Contexts" of once normal Rebol Contexts... 2) My intent was to describe the Rebol Context Handling and the refinements would complicate the code beyond the limit I considered acceptable. (BTW, if you consider Sim-function/spec as containing all Function Context's Words ie. Arguments, Refinements, Words specified as /local, everything holds, the things that should be added are the examination of a call-path used, a code to supply None as the value for respective Function Context's Words, a code for spec parsing and the type checking code.)