Parley promotion mechanism for vocabulary

[Hartmut Riesenbeck]

Hi René

Last year I was in a similar situation like you now. I tried to fix some bugs 
in parley and started to dig into parleys code. But this year I became very 
busy with another project and had no time to work on parley. But I appreciate 
that you do. So may I can give some hints. 

> 1)
> To me it seems it is some kind of Leitner system algorithm? Any further
I agre! Looks the same to me. 

> 2)
> What I'm unsure about is the pregrade. I recognized in the statistics that
> the progress is not as visible as I thought it should be after practicing.
The only place you can see if a word is pregrade, is the second line at the 
upper right corner in practice mode. For pregrade words the line starts with 
"Initial" (in German translation "Anfangs") and for grade words it starts with 
"Long term" (in German translation "Langfristig").

> What is the intention of pregrade?
I dug a bit in git and found out that Inge Wallin did development on this. 
Here is a log entry in libkeduvocdocument. But that was before I started with 
parley. I don't now the intention for introducing pregrades. May someone else 
do?

----------------------------------------------------------------------------------
commit f7769a8aace03445059577dafafd88db44f056e4
Author: Inge Wallin <inge at lysator.liu.se>
Date:   Fri Apr 25 07:57:17 2014 +0200

    Implement new fields: pregrade and interval
    
    This patch implements two new fields in a kvtml file:
     - pregrade, which is equal to grade but used in the interval 0-1 days
       as opposed to grade which is used for intervals 1 day and up.
     - interval, which is used to indicate how long since a word was last
       trained it is due for training again.
    
    This is prerequisite to the implementation in Parley of the initial
    training. The reason for implementing these two fields instead of
    changing old ones is that it will still be backward compatible. I
    think this is important, especially in the light of the ktouch issue
    that we saw on the mailing list a few days ago.
    
    REVIEW: 117730
---------------------------------------------------------------------------------------------

> From my understanding it would make sense to remove pregrade completely.
For my personal type of vocabulary learning, it's more effective with 
pregrades. But that's my personal feeling - not representative. May it's a 
good idea to make pregrade use configurable.


May I find some time in the next days to look for your other questions.

Cheers!
Hartmut