Add two examples

.idea/micronfig.iml

@@ -3,7 +3,10 @@
   <component name="NewModuleRootManager" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/examples" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/examples/e01_the_cave/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/examples/e01_the_cave/target" />
       <excludeFolder url="file://$MODULE_DIR$/target" />
     </content>
     <orderEntry type="inheritedJdk" />

examples/e01_the_cave/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "e01_the_cave"
+description = "Echoes back the value of ECHO."
+version = "0.0.0"
+edition = "2021"
+
+[dependencies]
+micronfig = { path = "../.." }

examples/e01_the_cave/src/main.rs

@@ -0,0 +1,9 @@
+use std::fmt::{Display, Formatter};
+use std::str::FromStr;
+
+fn main() {
+    let echo: String = micronfig::get("ECHO")
+        .expect("ECHO configuration value to be defined");
+
+    println!("ECHOing back: {echo}");
+}

examples/e02_quick_math/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "e02_quick_math"
+description = "Performs OPERATOR between FIRST and SECOND."
+version = "0.0.0"
+edition = "2021"
+
+[dependencies]
+micronfig = { path = "../.." }

examples/e02_quick_math/src/main.rs

@@ -0,0 +1,52 @@
+use std::fmt::{Display, Formatter};
+use std::str::FromStr;
+
+pub enum Operator {
+    Sum,
+    Subtraction,
+    Multiplication,
+    Division,
+}
+
+impl FromStr for Operator {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "+" => Ok(Self::Sum),
+            "-" => Ok(Self::Subtraction),
+            "*" => Ok(Self::Multiplication),
+            "/" => Ok(Self::Division),
+            _ => Err(())
+        }
+    }
+}
+
+impl Display for Operator {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", match self {
+            Self::Sum => "+",
+            Self::Subtraction => "-",
+            Self::Multiplication => "*",
+            Self::Division => "/",
+        })
+    }
+}
+
+fn main() {
+    let first: u64 = micronfig::get("FIRST")
+        .expect("FIRST operand to be properly defined");
+    let second: u64 = micronfig::get("SECOND")
+        .expect("SECOND operand to be properly defined");
+    let operator: Operator = micronfig::get("OPERATOR")
+        .expect("OPERATOR to be properly defined");
+
+    let result = match operator {
+        Operator::Sum => first + second,
+        Operator::Subtraction => first - second,
+        Operator::Multiplication => first * second,
+        Operator::Division => first / second,
+    };
+
+    println!("{first} {operator} {second} = {result}")
+}