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

[Andrey G. Grozin]

On Wed, 22 Jun 2005, Page, Bill wrote:
> > This is unreasonable. The purpose to edit earlier input lines may
> > also rearrange the order of execution of the lines. Only the user
> > knows what order of execution is needed for his/her purpose.
> I disagree. Given Axiom's history of the commands that have already
> been executed and a list of the modifications to the input lines
> (contents of the browser page), it is quite possible to determine
> the minimum number and order of (re-)execution and/or execution of
> new commands that is required to compute a consistent state.
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.

Andrey