Bit more of overview.

Author: mlajtos

docs/Overview.md

@@ -3,6 +3,15 @@
 ![Transformation pipeline](images/pipeline.png)
 
 ### Moniel
+#### PEG
+Moniel notation is a [PEG](https://en.wikipedia.org/wiki/Parsing_expression_grammar) language described by the [grammar](../moniel.ohm) and [semantics](../moniel.semantics.js) in [Ohm/JS](https://github.com/cdglabs/ohm).
+
+#### AST
+Ohm/JS creates abstract syntax tree that is processed by Moniel runtime which constructs the intermediate representation of computational graph.
+
+#### JSON, Protocol Buffers
+TensorFlow uses [Protocol Buffers](https://github.com/google/protobuf) for representing the computational graph. However, one can directly map a special JSON file through ProtoBuf schema to obtain a ProtoBuf definition suitable for TensorFlow runtime.
+
 ### Moniel IDE
 *Moniel IDE* stands for (Integrated | Interactive) (Development | Design) (Environment | Experience), where user can interactively design model with immediate feedback. For now, this stage is limited to model definition only. However, user should be able to interactively inspect model training and model evaluation – these are partly covered by TensorBoard.
 #### Editor