Squashed commit of the following:

commit 5992c7a752199d03c4050ad0753d3c9ce0b7e9c3
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Wed Sep 23 17:54:07 2020 +0200

    Added #import functionality when restoring

commit 30f6344ea1bac3fb00c47aaafb3048293040e067
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Wed Sep 23 12:27:13 2020 +0200

    Hardening questions management

commit 7bb325233ba6a8300d31439d5ad2cac22d7b4458
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Tue Sep 22 20:18:50 2020 +0200

    Enhanced error responses when using memory() and get_attr()

commit 04799364207aa7a8bd53b3a055d6452602968d8f
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Tue Sep 22 17:20:25 2020 +0200

    Hardened DefaultParser

commit 1fbacbbc452c4dfc32ac1dc88f97dc2b6686dca5
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Tue Sep 22 14:55:55 2020 +0200

    More unit tests for DefaultParser

commit 8ba2bb7c133b6ac29cbebba82fb5c6efed731a1f
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Tue Sep 22 09:57:49 2020 +0200

    You can use double quote when defining concept name

commit a494c64620034f352ecae15c9818b8074e9ca14e
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Mon Sep 21 21:29:41 2020 +0200

    fixed memory() and RET usage

commit 90c282af3d031bd6f9b5158c291b07d5e6bbe714
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Mon Sep 21 17:58:51 2020 +0200

    Working on Python Evaluator

commit e4e1dc28da095ef61d2dbc7dafe7a1f3ead3edd0
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Mon Sep 21 11:26:52 2020 +0200

    Fixed MemoryObject serialization

commit 7e7e1ed28a97e5fdea09c79ce501fb81f8d748a8
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Sat Sep 19 20:52:06 2020 +0200

    Working on memory objects serialization

commit 1390f8c6b852251d5c43fd5abb7ee3157c372e48
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Sat Sep 19 18:59:54 2020 +0200

    Working on memory objects

commit d72518df48ab8686ddcfc05c86d399af629c93de
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Sat Sep 19 16:16:31 2020 +0200

    Added basic memory management

commit 728224882156d9f18f339d5d588f13546ebd1479
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Fri Sep 18 23:44:56 2020 +0200

    Working on Memory

commit a452c1c1572d32692f1b32a79e04a560941e24a0
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Fri Sep 18 18:30:38 2020 +0200

    Working on long term memory management

commit 2decfa827259277b0e088623966056f7dbdb70ce
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Fri Sep 18 11:48:46 2020 +0200

    Added set_attr and set_attr

commit d46af547a0890e025c89e3d9e322bb439002cc21
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Fri Sep 18 10:31:14 2020 +0200

    Added auto_eval

commit 416e5beb075c82cf9d177c0ab18795ac6b9eca12
Author: Kodjo Sossouvi <kodjo.sossouvi@gmail.com>
Date:   Thu Sep 17 15:39:23 2020 +0200

    Added grammar update upon set modification

_concepts.txt

@@ -1,3 +1,4 @@
+#import admin
 def concept one as 1
 def concept two as 2
 def concept three as 3
@@ -88,13 +89,6 @@ set_is_greater_than(__PRECEDENCE, multiplied, plus)
 set_is_greater_than(__PRECEDENCE, divided, plus)
 set_is_greater_than(__PRECEDENCE, multiplied, minus)
 set_is_greater_than(__PRECEDENCE, divided, minus)
-def concept explain as get_results() | filter("id == 0") | recurse(2)
-def concept explain last as get_last_results() | filter("id == 0") | recurse(2)
-def concept explain x as get_results() | filter(f"id == {x}") | recurse(3) where x
-def concept explain x '--recurse' y as get_results() | filter(f"id == {x}") | recurse(y) where x,y
-set_isa(c:explain:, __AUTO_EVAL)
-set_isa(c:explain last:, __AUTO_EVAL)
-set_isa(c:explain x:, __AUTO_EVAL)
 def concept precedence a > precedence b as set_is_greater_than(__PRECEDENCE, a, b)
 set_isa(c:precedence a > precedence b:, __AUTO_EVAL)
 def concept x is a command as set_isa(x, __AUTO_EVAL)
@@ -103,5 +97,3 @@ def concept q from q ? as question(q) pre is_question()
 set_is_lesser(__PRECEDENCE, q)
 def concept x is a 'concept' as isinstance(x, Concept) pre is_question()
 def concept x is a y as isa(x,y) pre is_question()
-def concept explain x values where x as get_results() | filter(f"id=={x}") | format_d
-set_isa(c:explain x values:, __AUTO_EVAL)