From aaab0a4b2819a696c1790d5977ac1b51901cabbf Mon Sep 17 00:00:00 2001
From: Garrit Franke <garritfranke@gmail.com>
Date: Tue, 8 Dec 2020 21:25:56 +0100
Subject: [PATCH] Add conditional else if branch

---
 examples/playground.sb | 13 +++++--------
 src/generator/js.rs    |  5 +++++
 src/parser/mod.rs      | 12 +++++++++++-
 src/parser/tests.rs    | 36 ++++++++++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+), 9 deletions(-)

diff --git a/examples/playground.sb b/examples/playground.sb
index e51fc19..90b740c 100644
--- a/examples/playground.sb
+++ b/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)
-} 
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/src/generator/js.rs b/src/generator/js.rs
index 83a6c5a..1a9a57e 100644
--- a/src/generator/js.rs
+++ b/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
 }
 
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 9bbc6bc..ca10991 100644
--- a/src/parser/mod.rs
+++ b/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.
diff --git a/src/parser/tests.rs b/src/parser/tests.rs
index c1b89b6..2267df4 100644
--- a/src/parser/tests.rs
+++ b/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())
+}