Add conditional else if branch

examples/playground.sb

@@ -1,11 +1,8 @@
 fn main() {
     let num = 10
-    return fib(num)
-}
-
-fn fib(n) { 
-    if 1 >= n {
-        return n
+    if num > 5 {
+        return num
+    } else if num <= 5 {
+        return 1
     }
-    return fib(n-1) + fib(n-2)
 }

src/generator/js.rs

@@ -75,6 +75,11 @@ fn generate_conditional(
         outcome += &generate_statement(statement);
     }
     outcome += "}";
+
+    if let Some(else_state) = else_state {
+        outcome += "else ";
+        outcome += &generate_statement(else_state);
+    }
     outcome
 }
 

src/parser/mod.rs

@@ -316,7 +316,17 @@ impl Parser {
 
         self.match_token(TokenKind::CurlyBracesClose)?;
 
-        Ok(Statement::If(condition, statements, None))
+        match self.peek() {
+            Some(tok) if tok.kind == TokenKind::Keyword(Keyword::Else) => {
+                self.next_token();
+                Ok(Statement::If(
+                    condition,
+                    statements,
+                    Some(Box::new(self.parse_conditional_statement()?)),
+                ))
+            }
+            _ => Ok(Statement::If(condition, statements, None)),
+        }
     }
 
     /// In some occurences a complex expression has been evaluated before a binary operation is encountered.

src/parser/tests.rs

@@ -262,3 +262,39 @@ fn test_parse_basic_conditional_with_multiple_statements() {
     let tree = parse(tokens, Some(raw.to_string()));
     assert!(tree.is_ok())
 }
+
+#[test]
+fn test_parse_conditional_else_if_branch() {
+    let raw = "
+    fn main(n) {
+        if n > 10 {
+            let x = 2 * n
+            return x
+        } else if n <= 10 {
+            return n
+        }
+    }
+    ";
+    let tokens = tokenize(raw);
+    let tree = parse(tokens, Some(raw.to_string()));
+    assert!(tree.is_ok())
+}
+
+#[test]
+fn test_parse_conditional_multiple_else_if_branch_branches() {
+    let raw = "
+    fn main(n) {
+        if n > 10 {
+            let x = 2 * n
+            return x
+        } else if n < 10 {
+            return n
+        } else if n == 10 {
+            return n + 1
+        }
+    }
+    ";
+    let tokens = tokenize(raw);
+    let tree = parse(tokens, Some(raw.to_string()));
+    assert!(tree.is_ok())
+}