Ignacio writes:
 I think may be useful to have a command that clears the series 
 in the dataset without deleting from memory the currently 
 defined matrices. This will do easier to deal with data in 
 different disagregation periods. 
 It can be also convenient to have a text command equivalent to 
 /File/clear dataset, and another text command equivalent to 
 /File/Append data 
The simple point first: the "append" command does what 
/File/Append data does.
As for clearing data, I've put some experimental things is place.
For the script equivalent of "/File/Clear data set" I've added a 
"clear" argument to the "dataset" command.  That is, you say
  dataset clear
But this has a "preserve" option:
  dataset clear --preserve
which has the effect that existing named matrices are not 
destroyed.
Similarly, the commands "open" and "nulldata" have a --preserve 
option: clear most stuff out, but keep matrices.
At present the --preserve option does not have a GUI counterpart.
Allin.