add fib and update readme

README.md

@@ -124,22 +124,24 @@ But we want to take a different path with respect to:
 - No marker traits like Send, Sync for concurrency. The runtime will take care of that.
 
 ## Syntax
-```
-mod FibonacciModule {
-
- pub fib(x: u64) -> u64 {
-     match x {
-       // we can match literal values
-       0 | 1 -> x,
-       n -> fib(n-1) + fib(n-2)
-     }
- }
+```rust
+mod Fibonacci {
+    fn main() -> i64 {
+        return fib(10);
+    }
+
+    pub fn fib(n: u64) -> u64 {
+        if n < 2 {
+            return n;
+        }
+
+        return fib(n - 1) + fib(n - 2);
+    }
 }
 ```
 
-```
+```rust
 mod Option {
-
     pub enum Option<T> {
         None,
         Some(T),

crates/concrete_driver/tests/programs.rs

@@ -56,6 +56,31 @@ fn test_factorial_with_if() {
     assert_eq!(code, 24);
 }
 
+#[test]
+fn test_fib_with_if() {
+    let source = r#"
+        mod Fibonacci {
+            fn main() -> i64 {
+                return fib(10);
+            }
+
+            pub fn fib(n: u64) -> u64 {
+                if n < 2 {
+                    return n;
+                }
+
+                return fib(n - 1) + fib(n - 2);
+            }
+        }
+    "#;
+
+    let result = compile_program(source, "fib", false).expect("failed to compile");
+
+    let output = run_program(&result.binary_file).expect("failed to run");
+    let code = output.status.code().unwrap();
+    assert_eq!(code, 55);
+}
+
 #[test]
 fn test_simple_add() {
     let source = r#"

examples/fib_if.con

@@ -0,0 +1,13 @@
+mod Fibonacci {
+    fn main() -> i64 {
+        return fib(10);
+    }
+
+    pub fn fib(n: u64) -> u64 {
+        if n < 2 {
+            return n;
+        }
+
+        return fib(n - 1) + fib(n - 2);
+    }
+}