TODO

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# To Do list for ELIPS 
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0. Unit tests
1. Retire operation support (work in engine) [Done]
2. Garbage Collection
    2.1. Introduce life time for Working Memory Element (WME)
    2.2. Elaborate eviction policies
    2.3. Implement GC server
    2.4. Implement 'linking' of a facts to processes. 
         I.e. some asserted fact may have sense only 
         while some process is alive and must be retired 
         (or replaced by some other asserts) when process 
         finishes.
3. Elaborate more memory effective architecture of a Working Memory (WM) 
    Note: It seems it is a good idea to have an explicit 
    Alpha memory (AM) as a separated ETS where each fact 
    have an integer index. Beta memory (BM) in this case 
    contains tokens as a lists of integers.
4. Its probably a good idea to have a clauses args reversed 
   (work in builder) to avoid lists:reverse or ++ operations in engine. 
5. Give access to alpha memory form a call back module   
6*. Back tracking & goal satisfaction

Known Bugs [fixed]

1. LHS patterns not connected by variables i.e. having more that one 
   connected components by vars are incorrectly handled.
2. The order of alpha forms in a last beta node may differ from
   order in original rule LHS pattern, e.g.:
        [{A,has,B},{C,has,D},{B,has,C}]