[m-dev.] storing GetVars vs Vars Re: source-to-source debugger proposal

[Zoltan Somogyi]

On 02-Oct-2007, Peter Moulder <Peter.Moulder at infotech.monash.edu.au> wrote:
> > That is your misconception. There is no type-safe way to fill the closure
> > without doing *everything* that the GetVars approach [presumed typo
> > for Vars approach or (equivalently) the implementation of the GetVars
> > function] does, not unless you get *below* the source level.
> 
> It is unfortunate that something so endemic to logic/functional
> programming as a closure call must involve chasing a linked list of
> univ's, when the function already knows the number & (often) type of its
> arguments, and the caller is compiler-generated.

This is NOT "endemic" to creating closures. It is a problem that arises
because of the mismatch between (a) the fact different predicates have
different sets of variables, with different names and types, and (b) the
fact that the argument of the debugger's port predicates that represent
the variables of all these user predicates must have a single type.

Zoltan.
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