--history usage

[RS]

What is the significance of the index numbers returned by a search 
with --history?  They are clearly not cache index numbers.  In one case when 
I searched for a tv programme using a cache index and --history I got a 
radio programme even though I had used --type=tv.  That is probably because, 
unlike the cache, there is only one history file for both.  Curiously a lot 
more information is returned for --type=radio than --type=tv.

Clearly the main function of the history file is to enable get_iplayer to 
warn when programmes have already been recorded, and to require --force if 
the programme is to be recorded again.  The information it stores goes far 
further than that.  Is there any easy way of getting the complete records? 
One way of doing it would be to load the file into Wordpad and then search 
for the PID.  I have often thought it would not be too difficult to write a 
small C or Python program to export it to a database or spreadsheet to make 
it more searchable, but if get_iplayer already has the capability there is 
no need.