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

docs/src/start/standalone.md

@@ -1 +1,116 @@
 # Using Steel on its own
+
+## 0. 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!
+
+## 1. Installing Steel Interpreter
+
+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.
+
+
+## 2. Updating interactive shell environment
+
+  1. Add the portable binary executable path name to your `PATH` environment variable.
+
+    - For those who adopt Bash or Zsh as their daily driver, simply feed the new path like the following:\
+  `export PATH=~/\<your/path/to/steel/directory\>/target/release:$PATH`
+
+  2. Then run the subsequent command to regenerate your environment variable:\
+  `source ~/.bashrc`
+
+    - With respect to `Fish` shell users, simply proceed this way:\
+  `fish_add_path \<your/path/to/steel/directory\>/target/release`
+
+  3. From now on, you may wish to reload your interactive shell with the newly added environment variable like so:\
+  `source ~/.config/fish/config.fish`
+
+  - And for those who make use of `elvish` as their beloved shell, add the following into your `rc.elv` file:\
+  ```
+  set paths = [
+    ~/\<your/path/to/steel/directory\>/target/release`
+  $@paths]
+  ```
+
+  4. Finally, just type:\
+  `exec elvish`
+
+  You can optionally check if your $paths environment variable has been properly fed with the new path name:\
+  `pprint $paths`
+
+
+## 3. Executing a Steel program
+
+  You can compile and execute your Steel programs from your terminal like so:\
+  `steel \<steel_file.scm\>`
+
+
+## 4. Preparing ground for subsequent Steel packages
+
+  You can optionally define `STEEL_HOME` as a sub-directory of your choice to set up properly a path name for your
+  subsequent Steel package's installations.\
+  Like before, forget not to regenerate your interactive shell to activate the new path name without having to start a
+  new user session.
+
+
+## 5. Updating the Steel compiler
+
+  0. The modus operandus is straightforward. Navigate through your installation path:
+  cd <path/to/steel/installation/repertoire`
+
+  1. Simply fetch the latest changes from the official Steel repository to update your local one by running the
+  following command:\
+  `git pull [--rebase]`
+
+  The optional flag may be required to avoid rebasing some non-local changes if the upstream branch was rebased since
+  last fetched.
+
+  2. Re-run the build using `cargo` package manager with one command or the other:
+  `cargo install --path .` / `cargo build --release`