Drivers UI: Added name validation/linting for Driver Variables

When attempting to change a driver variable name to an "invalid" name,
an indicator will now be shown beside the offending variable name.
Clicking on this icon will show a popup which provides more information
about why the variable name cannot be used.

Reasons that it knows about are:
1) Starts with number
2) Has a dot
3) Has a space
4) Starts with or contains a special character
5) Starts with an underscore (Python does allow this, but it's bad practice,
   and makes checking security of drivers harder)
6) Is a reserved Python keyword

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_fcurve.h b/source/blender/blenkernel/BKE_fcurve.h
index 443a03a475a..a1176b91312 100644
--- a/source/blender/blenkernel/BKE_fcurve.h
+++ b/source/blender/blenkernel/BKE_fcurve.h
@@ -95,6 +95,7 @@ struct ChannelDriver *fcurve_copy_driver(struct ChannelDriver *driver);
 
 void driver_free_variable(struct ChannelDriver *driver, struct DriverVar *dvar);
 void driver_change_variable_type(struct DriverVar *dvar, int type);
+void driver_variable_name_validate(struct DriverVar *dvar);
 struct DriverVar *driver_add_new_variable(struct ChannelDriver *driver);
 
 float driver_get_variable_value(struct ChannelDriver *driver, struct DriverVar *dvar);