Currently, the 'Add function' dialog determines the set of available functions based on the dtypes of the columns that were selected when the dialog was opened. However, if the column selection changes in the dialog, the function set may not be appropriate anymore.
Instead, the column selector should emit a signal whenever the selection changes. When receiving this signal, the dialog should create a set containing the dtypes of the new column selection. This set is then matched against a set of valid dtypes that is stored in each function class. Only those function classes will be shown in which the current dtype set is a subset of the set of valid dtypes.
Currently, the 'Add function' dialog determines the set of available functions based on the dtypes of the columns that were selected when the dialog was opened. However, if the column selection changes in the dialog, the function set may not be appropriate anymore.
Instead, the column selector should emit a signal whenever the selection changes. When receiving this signal, the dialog should create a set containing the dtypes of the new column selection. This set is then matched against a set of valid dtypes that is stored in each function class. Only those function classes will be shown in which the current dtype set is a subset of the set of valid dtypes.