[DOC] Adding a brief documentation for standalone sub-section's Steel book

docs/src/start/standalone.md

@@ -1 +1,85 @@
 # Using Steel on its own
+
+## Preambule
+This document includes some features of ABNF (Augmented Backus Naur form), which is a meta-language used to define
+another language and proves itself always useful in documentations associated with programming languages and softwares.
+To know more about its full specifications, see: [RFC5234](https://www.rfc-editor.org/rfc/rfc5234) and its superseeded
+RFC at [RFC7405](https://www.rfc-editor.org/rfc/rfc7405) (fixing case-sensitivity).
+
+The main considerations are defined as follow:
+  - \<file\> = defines a logical entity between angle brackets, with a concept's name or identifier
+  - \<cmd-1\> / \<cmd-2\> = a *solidus* (as named by the Unicode consortium, more commonly known as "slash") stands for "alternative
+  OR" (also known as XOR, or exlusive OR) and is inserted between two operands, forms, or S-expressions.
+  - [option] = a optional concept is encompassed between square brackets.
+  - ``=` = the equal sign is not a affection per-se but stands for a business rule that is defined by a associated name.
+    That is to say: \<name\> = \<rule\>
+
+Of course, those semantic mechanisms will NOT appear anywhere in your command lines!
+
+## Installation
+You can use and enjoy all features provided by the Steel Interpreter by installing it and running it on its own.
+
+1. To proceed, let us start by cloning the official Steel project's repository:\
+  `git clone https://github.com/mattwparas/steel` [my_custom_target_name]
+
+*Nota bene*: A second optional argument allows you to customize the target directory (*i.e.* steel_lang)
+
+2. Rendez-vous into the newly created directory:\
+`cd steel / \<custom_dir_name\>`
+
+3. You have 3 slightly different manners to make use of the Steel interpreter:\
+  - You can rely on the Rust package manager (*i.e.* Cargo):\
+    `cargo run`\
+    It will install all the required crates to prepare your environment, which are merely dependencies in Rust 
+    ecosystem's vocabulary.
+
+    Then run `cargo run -- \<steel_file.scm\>` every time you need to execute the said Steel file.\
+
+    That is all for this sub-section if you decide to take this route!
+
+  - Alternatively, you can install the Steel interpreter and simply run it as it is a more straightforward way to 
+  proceed. To achieve this, here is the canonical way to install a package with Cargo:\
+  `cargo install --path .`
+
+*Nota bene*: forget not the trailing dot (*i.e.* `.`) as it represents your current working directory.
+
+  - There is a second manner to install Steel interpreter with Cargo. The only difference is that it reads your 
+  `cargo.lock` file if it exists.\
+  As a side note, having added the `--locked` flag to the previous `cargo install --path .` command would have 
+  produced the exact same result than the following one.\
+
+  Simply run:\
+  `cargo build --release`
+
+  The release flag will take a bit longer to build all the file objects due to optimization passes but will act faster
+  when executing subsequent runs.
+
+### Updating interactive shell environment
+
+  4. Add the portable binary executable path name to your `PATH` environment variable.\
+  For those of you who have seen the light and use `elvish` as your mainly driver, add the following into your `rc.elv`
+  file:
+  ```
+  set paths = [
+    ~/\<your/path/to/steel/directory\>/target/release`
+  $@paths]
+  ```
+
+  5. Then run `exec elvish` and your are good to go! You can check your newly added path by typing:\
+  `pprint $paths`
+
+    - For those who still live in the dark caves of ancient shells like Bash or Zsh, simply feed the new path like the
+  following:\
+  `export PATH=~/\<your/path/to/steel/directory\>/target/release:$PATH`
+
+    - And with regard to `Fish` shell users, simply proceed this way (lucky you!):\
+  `fish_add_path \<your/path/to/steel/directory\>/target/release`
+
+    - `sh`, `bash`, `zsh` and `fish` users now have to regenerate their environment variables by running:\
+  `source ~/.bashrc` / `source ~/.config/fish/config.fish` (depending on your kryptonite)
+
+
+## Running a Steel file
+
+  6. Finally, compile and execute your Steel files from your terminal like so:\
+  `steel \<steel_file.scm\>`