Re: [Axiom-developer] Lazy re-evaluation (was: More AxiomUI)

[Bob McElrath]

Andrey G. Grozin address@hidden wrote:
> I disagree. Only the user can decide *which* consistent state [s]he wants.
> Suppose there is a code fragment
> n:=1
> x:=f(n)
> n:=2
> y:=f(n)
> Do you consider the state of Axiom after it inconsistent? I don't. This is 
> an imperative language, after all. If the user edits the first line to 
> read
> n:=3
> and then re-executes the second line, are you sure the user wants to 
> re-execute the fourth line too? I am not. I'd hate it if the system would 
> make such decisions for me.

You have done two things:
1) edit a line
2) re-evaluate an *un-edited* line

With lazy re-evaluation, (2) would never be needed.  (and in fact,
doesn't make sense because the output would always be identical)

When I have said inconsistent, I mean that if I re-execute the commands
in order, I get something different than currently appears as output in
the worksheet.

In fact perhaps the concept of "executing" a block should go as well.
There would only be a concept of "done-editing" a block, at which point
the interface would go evaluate whatever was necessary.  One would never
go back and re-evaluate something unless an edit was made on *that*
line.

--
Cheers,
Bob McElrath [Univ. of California at Davis, Department of Physics]

    "One of the best ways to get yourself a reputation as a dangerous citizen
    these days is to go about repeating the very phrases which our founding
    fathers used in the great struggle for independence." --Charles A. Beard

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