chapter 2.2 - Execute a process

src/SUMMARY.md

@@ -4,5 +4,6 @@
 - [Getting Started](ch01-00-getting-started.md)
 - [How to](ch02-00-how-to.md)
   - [Initializing Bastion](ch02-01-initializing-bastion.md)
+  - [Execute a process](ch02-02-execute-a-process.md)
 - [Appendix](appendix-00.md)
   - [Definition](definition-01.md)

src/appendix-01-definition.md

@@ -2,6 +2,10 @@
 
 Quick explanation of some words you will encounter.
 
+## Actor Model
+
+TODO
+
 ## Backtraces
 
 > To find the cause of something by examining past events.
@@ -46,3 +50,7 @@ fn main() {
     Finished dev [unoptimized + debuginfo] target(s) in 0.79s
      Running `target/debug/examples/hide_backtraces`
 ```
+
+## Future
+
+TODO

src/ch02-00-how-to.md

@@ -1,3 +1,7 @@
 # How to
 
 In this section we will talk about the principal features of bastion, with a functional approach.
+
+The examples are just illustrating the purpose explained in the current section, not more, not less. We will complexify them during the book by adding new notions. If you need to have complete use cases you can find them in the [example section][example section] of the bastion repository.
+
+[example section]: https://github.com/bastion-rs/bastion/tree/master/src/bastion/examples

src/ch02-02-execute-a-process.md

@@ -0,0 +1,27 @@
+# Execute a process
+
+Bastion is an actor-model-like concurrency. In the `Actor Model`\* we find some `Actor` which are made to process computation. In Bastion we have the `Children`.
+
+A `Children` is spawned by using `Bastion::children();`. It take a `init` closure as parameter, it take the new `Children` as an argument and returning it once configured.
+
+## Exec
+
+The new `Children` passed in the `init` closure as parameter, will be used to configure itself. `with_exec();` sets the closure that will be used by every child of this children group. It take a `BastionContext` as parameter and return a `Future`\*.
+
+When a process is started, a **new context** will be assigned. Passed through the `init` closure and poll the future until it complete or abort. The future's output must be a `Result<(), ()>`.
+
+```rs
+use bastion::prelude::*;
+
+fn main() {
+    Bastion::init();
+    Bastion::start();
+
+    Bastion::children(|children| children.with_exec(|_ctx: BastionContext| async { Ok(()) }))
+        .expect("Couldn't create the children group.");
+
+    Bastion::stop();
+}
+```
+
+\*`Actor Model`: Appendix - Definition \*`Future`: Appendix - Definition