Support next review date in IR

[tvhong]

Is your feature request related to a problem? Please describe. Currently, the Priority Queue feature in IR add-on only supports a priority value for each card.

There are two main ways a user can use the priority queue:

1. Assign priority number for each card and frequently "randomize" the priority queue.
2. Does not use per-card priority number and use the priority queue as a first-in-first-out queue.

However, both these approaches have shortcomings when a user has many cards in the queue (hundreds). Approach (1) prevents the user from ever getting down to the lower priority cards. Approach (2) means the user spends too little time on the important cards and too much time on unimportant ones.

In SuperMemo, apart from a priority, each topic (equivalent to IR card) also has a next review date. Everyday, SuperMemo creates a list of outstanding repetitions for all topics whose "next review date" is on that day. Additionally, topics within the outstanding repetitions queue are ranked based on their priority. During the learning session, the user reviews the highest priority topic first. And if the user does not finish the outstanding repetition queue for that day, subsequent topics are rescheduled for a later day.

The algorithm for rescheduling leftover topics from the outstanding repetitions queue is described below:

the algorithm for determining inter-review intervals for topics is much simpler and is entirely under your control. Each article receives a specific priority. The priority determines which articles are reviewed first and which can be postponed in case you run out of time. Each article is also assigned a number called the A-Factor that determines how much intervals increase between subsequent reviews. For example, if A-Factor is 2, review intervals will double with each review. Priority and A-Factors are set automatically, but you can change them manually at any time. Priorities and A-Factors are determined and modified heuristically on the basis of the length of the text, the way it is processed, the way it is postponed or advanced, and by many other factors.

http://super-memory.com/help/il.htm

Describe the solution you'd like

• Each IR card has "next review day".
• Support daily "outstanding repetitions" queue where IR cards are ranked based on priority.
• Users can view and edit next review day for IR cards.
• Untouched IR cards from "outstanding repetitions" are re-scheduled for a later date.