MI & pretty-printing

Nick Roberts
2009-07-14T01:55:00Z

Vladimir Prus writes:
>
> On IRC, Tom and I talked about best way to support Python
> pretty-printing with MI. Here's my attempt at summarizing.
>
> 1. It does not seem like existing frontends can make use of
> pretty-printing automatically. If frontend tries to list
> children of an invalid value, GDB may just hang. If GDB
> automatically limits the number of children, then existing
> frontends will not be able to see the children beyond this
> limit (or have GUI for that). Therefore, it is suggested than
> a new MI command is used to explicitly enable pretty-printing
> in MI, say
>
> -enable-pretty-printing [0|1]
>
> 2. The FE may request a specific range of children by passing
> low and high boundary:
>
> -var-list-children varobj [low] [hi]

When I submitted patches for similar functionality in April/May
of last year, I proposed a third parameter, stride, or step size,
to sample a large array. ISTR Solaris dbx and Totalviewallow(ed) allow
printing array slices in this way.

first patch: http://sourceware.org/ml/gdb-patches/2008-04/msg00493.html
final patch: http://sourceware.org/ml/gdb-patches/2008-05/msg00328.html

> If no range is specified, an attempt to report all children is
> made, be what may.
>
> 3. A varobj keeps a range of children to fetch on -var-update, and
> a new command is added to set that range, say,
>
> -var-set-update-range varobj low hi

I think -var-set-update-range would be a useful addition.

--
Nick http://www.inet.net.nz/~nickrob