Meta processor

- Described the role (via some examples) of the meta processor

docs/implementation/38-meta.md

@@ -9,6 +9,15 @@ that *consumes the AST tree*, applies manipulations to its nodes or
 completely replaces some, and then finally returns to let the type
 checker begin its process.
 
+Examples of things which require AST manipulation are:
+
+1.  Type aliases
+    - `size_t` and `ssize_t` need to be resolved to their concrete types
+2.  Macros
+    - Macros such as `sizeof(<type>)` need to be replaced with a
+      `NumberLiteral` with the value that is equal to the bit-width (in
+      bytes) of the type `<type>`
+
 ### Meta API
 
 There are some core interfaces which various `Statement`(s) (parser
@@ -70,4 +79,16 @@ TODO: Add an example of it being used here please
 
 ### the `MetaProcessor`
 
+The `MetaProcessor` is the actual processing facility which can apply
+different types of AST manipulations to a given `Container`. It is run
+prior to type checking but after parsing. This makes sense as we want to
+do AST node manipulation *just* after the parse tree has been
+constructed, then we can pass the changed program to the `TypeChecker`
+and it wouldn’t know any different. For all the type checker knows, this
+is just the original program.
+
 TODO: Document me
+
+| Method name | Return type | Description                           |
+|-------------|-------------|---------------------------------------|
+| `clone()`   | `Statement` | Returns the deeply cloned `Statement` |

docs_src/implementation/38-meta.md

@@ -2,6 +2,13 @@
 
 The _meta processor_ is a mechanism that acts somewhat like a _shim_ (something you shove in-between two things) between the _parser_ and the _typechecker_. Therefore because the parser provides us with an AST tree rooted in a `Module` of which is then passed to the type checker it would imply that the place where the meta processor fits in is something that _consumes the AST tree_, applies manipulations to its nodes or completely replaces some, and then finally returns to let the type checker begin its process.
 
+Examples of things which require AST manipulation are:
+
+1. Type aliases
+    * `size_t` and `ssize_t` need to be resolved to their concrete types
+2. Macros
+    * Macros such as `sizeof(<type>)` need to be replaced with a `NumberLiteral` with the value that is equal to the bit-width (in bytes) of the type `<type>`
+
 ### Meta API
 
 There are some core interfaces which various `Statement`(s) (parser nodes) can implement in order to be able to be manipulated by the meta-processor, we describe these in this section. These are all defined in `source/tlang/compiler/symbols/mcro.d`.
@@ -60,4 +67,13 @@ TODO: Add an example of it being used here please
 
 ### the `MetaProcessor`
 
-TODO: Document me
+The `MetaProcessor` is the actual processing facility which can apply different types of AST manipulations to a given `Container`. It is run prior to type checking but after parsing. This makes sense as we want to do AST node manipulation _just_ after the parse tree has been constructed, then we can pass the changed program to the `TypeChecker` and it wouldn't know any different. For all the type checker knows, this is just the original program.
+
+
+TODO: Document me
+
+
+
+|   Method name    | Return type  |     Description                             |
+|------------------|--------------|---------------------------------------------|
+| `clone()`        | `Statement`  | Returns the deeply cloned `Statement`       |