Refactored to allow ConceptEvaluator

docs/Concept_properties.md

@@ -0,0 +1,56 @@
+class Concept:
+ * name
+ 
+    human reading name of the concept. It is how the concept will be referenced
+ * is_builtin
+    
+    Simple flag to make the difference between user defined concept and builtins
+    
+  * is_unique
+  
+    To manage singleton. There should be only one instance of the concept if True
+  
+  * key
+  
+    It is the name of the concept, where all variables, or the obj are replaced by
+    __var__x (x is the number of the variable). It's use to quickly find concepts
+    with variables
+    
+  * id
+  
+    The key is the unique identifier for the class of concept. The concept may be
+    modified along its life, but its key will never change
+
+  * where
+    
+    preconditions for the variables of the concept. Body will be executed only 
+    if the where conditions on the properties are True 
+
+  * pre
+    
+    Execution context to verified before executing the context
+
+  * post
+    
+    Post conditions to verify, once the context is executed
+  
+  * obj
+    
+    main or principal subject of the concept
+  
+  * body
+  
+    Code or value of the concept
+    
+   * desc
+   
+     explanation of the concept
+    
+    * digest
+     
+        SHA 256 of all properties. It allows 
+     
+    * props
+    
+        other properties of the concept (obj is the first one)
+    

docs/blog.rst

@@ -382,4 +382,18 @@ so I can type
     1 + 1
     sheerka.test()
 
-I will now work on how to call an already defined concept.
+I will now work on how to call an already defined concept.
+
+
+2019-11-11
+**********
+
+Maintaining the blog
+""""""""""""""""""""
+It's not very easy to maintain this blog. Every time I have some time to work on **Sheerka**,
+I must choose between expressing my ideas in this blog and coding.
+
+I have plenty of ideas that I would like to express, sometimes just to put the idea down,
+but I lack of time. It would be great if I can find a tool that will allow me to just to
+dictate my words. I know that there are plenty out there, I need to spend some time to test
+them and choose one. 

docs/syntax_v3.md

@@ -1,6 +1,10 @@
+In this example, I try to think of how I can deal with errors
 ```
 > "hello
 -> unfinished quote "
+
+create a concept to recognize the error
+
 > def concept unfinished quote q
 ... where:
 ...... q in ('"', '"')
@@ -9,9 +13,16 @@
 ... input = sheerka.last_input
 
 
+Create the rule to manage the error
+
 > when unfinished quote q as c:
-... add rule as:
-...... if q in sheerka.input:
+... add rule r as:
+...... if q is last of sheerka.input:
 ......... sheerka.resume(c, c.input + input)
-......... remove rule 
-```
+......... remove r 
+
+def concept a is last of b as:
+    where b is list
+    as b[-1] == a
+```
+