Re: Replacement for SCM_SETJMPBUF?

[Gary Houston]

> From: Rob Browning <address@hidden>
> Date: Fri, 14 Sep 2001 17:35:28 -0500
> 
> Gary Houston <address@hidden> writes:
> 
> > It's just a slightly modified version of scm_internal_cwdr from root.c
> > in guile-1.3.4 and earlier.  scm_internal_cwdr implements
> > call-with-dynamic-root.  The change that's been made is to avoid
> > unwinding/rewinding the caller's wind list around the callee
> > procedure.
> 
> But I presume that the other properties still hold (i.e. can only
> return from the call one time, errors can't throw past this point,
> etc.)

This will be the case, since the winding/rewinding doesn't affect these
properties.

> > So a quick fix would be to take a new cut-and-paste from guile 1.5 and
> > apply the change again (see below for some untested code).
> 
> OK.  Perhaps I'll try that, though in the long run, and as you suggest
> below, I'd like to have a supported solution, or fix guppi to handle
> things some other (more acceptable) way.

A short term fix to Guile should be acceptable if it's backwards
compatible.

> > If guppi and scwm both needed this ability then maybe it's a flaw in
> > Guile that it's not provided.
> 
> Could be.  I guess it depends on exactly what semantics they really
> need, and whether or not this is the most appropriate way to provide
> them.  I don't know enough about what guppi needs to do here to say
> for sure yet.