Convenience variable for filename in add-symbol-file not expanded

[David Lamy-Charrier]

I am using the add-symbol-file command from a gdb script to
dynamically add symbols at runtime.
So I want to use a convenience variable for the filename parameter of
add-symbol-file, I tested with gdb 6.3.1 for mingw and looked in the
code but convenience variables as filename are not expanded.

I found this thread:
http://www.cygwin.com/ml/gdb/2002-11/msg00275.html
But I do not know the current status of it.

Does anyone know if a patch exists for that ?
If not, could you give me some hints to implement it (any
parse_and_eval_string or equivalent i can use...) ?

Thanks in advance,
David