Add a way to temporarily set a gdb parameter from Python

It's sometimes useful to temporarily set some gdb parameter from
Python.  Now that the 'endian' crash is fixed, and now that the
current language is no longer captured by the Python layer, it seems
reasonable to add a helper function for this situation.

This adds a new gdb.with_parameter function.  This creates a context
manager which temporarily sets some parameter to a specified value.
The old value is restored when the context is exited.  This is most
useful with the Python "with" statement:

   with gdb.with_parameter('language', 'ada'):
      ... do Ada stuff

This also adds a simple function to set a parameter,
gdb.set_parameter, as suggested by Andrew.

This is PR python/10790.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=10790

1 files changed, 26 insertions, 0 deletions

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index f02380a..39bf6e8 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -332,6 +332,32 @@ parameter's value is converted to a Python value of the appropriate
 type, and returned.
 @end defun
 
+@findex gdb.set_parameter
+@defun gdb.set_parameter (name, value)
+Sets the gdb parameter @var{name} to @var{value}.  As with
+@code{gdb.parameter}, the parameter name string may contain spaces if
+the parameter has a multi-part name.
+@end defun
+
+@findex gdb.with_parameter
+@defun gdb.with_parameter (name, value)
+Create a Python context manager (for use with the Python
+@command{with} statement) that temporarily sets the gdb parameter
+@var{name} to @var{value}.  On exit from the context, the previous
+value will be restored.
+
+This uses @code{gdb.parameter} in its implementation, so it can throw
+the same exceptions as that function.
+
+For example, it's sometimes useful to evaluate some Python code with a
+particular gdb language:
+
+@smallexample
+with gdb.with_parameter('language', 'pascal'):
+  ... language-specific operations
+@end smallexample
+@end defun
+
 @findex gdb.history
 @defun gdb.history (number)
 Return a value from @value{GDBN}'s value history (@pxref{Value