Add a new implementation in rust

.gitignore

@@ -0,0 +1 @@
+rust-calc/target

rust-calc/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "rust-calc"
+version = "0.1.0"

rust-calc/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "rust-calc"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

rust-calc/src/main.rs

@@ -0,0 +1,81 @@
+use std::process;
+
+#[derive(Debug)]
+enum Symbol {
+    Minus,
+    Plus,
+    Multiply,
+    Divide,
+}
+
+struct TmpNum {
+    s: String,
+}
+impl TmpNum {
+    pub fn new() -> Self {
+        Self { s: String::new() }
+    }
+    fn push(&mut self, c: char) {
+        self.s.push(c);
+    }
+    fn get(&mut self) -> f32 {
+        let n = self.s.parse::<f32>().ok().expect("number is malformed");
+        self.s = String::new();
+
+        n
+    }
+}
+
+fn parse(pattern: String) -> (Vec<Symbol>, Vec<f32>) {
+    let mut symbols = Vec::new();
+    let mut numbers = Vec::new();
+
+    let mut number = TmpNum::new();
+
+    for c in pattern.chars() {
+        let s: Option<Symbol> = match c {
+            '-' => Some(Symbol::Minus),
+            '+' => Some(Symbol::Plus),
+            '*' => Some(Symbol::Multiply),
+            '/' => Some(Symbol::Divide),
+
+            _ => None,
+        };
+
+        match s {
+            Some(s) => {
+                symbols.push(s);
+                numbers.push(number.get());
+            }
+            None => {
+                number.push(c);
+            }
+        }
+    }
+
+    numbers.push(number.get());
+
+    (symbols, numbers)
+}
+
+fn main() {
+    let pattern = match std::env::args().nth(1) {
+        None => {
+            println!("Input must be provided");
+            process::exit(1)
+        }
+        Some(s) => s,
+    };
+
+    let (symbols, numbers) = parse(pattern);
+
+    println!("{:?}", symbols);
+    println!("{:?}", numbers);
+
+    let mut counter = 0;
+    let mut n1 = numbers.get(0).expect("expect at least the first value");
+    while counter < symbols.len() {
+        let mut n2 = numbers.get(counter+1).expect("expect at least a second value");
+        counter +=1;
+    }
+}