else if

src/main/scala/millfork/parser/MfParser.scala

@@ -420,7 +420,7 @@ case class MfParser(filename: String, input: String, currentDirectory: String, o
   def ifStatement: P[ExecutableStatement] = for {
     condition <- "if" ~ !letterOrDigit ~/ HWS ~/ mlExpression(nonStatementLevel)
     thenBranch <- AWS ~/ executableStatements
-    elseBranch <- (AWS ~ "else" ~/ AWS ~/ executableStatements).?
+    elseBranch <- (AWS ~ "else" ~/ AWS ~/ (ifStatement.map(_ :: Nil) | executableStatements)).?
   } yield IfStatement(condition, thenBranch.toList, elseBranch.getOrElse(Nil).toList)
 
   def whileStatement: P[ExecutableStatement] = for {

src/test/scala/millfork/test/BasicSymonTest.scala

@@ -116,4 +116,21 @@ class BasicSymonTest extends FunSuite with Matchers {
       """.stripMargin)
       m.readWord(0xc000) should equal(344)
   }
+
+  test("Else if") {
+    val m = EmuUnoptimizedRun(
+      """
+        | byte output @$c000
+        | void main () {
+        |  if 1 == 2 {
+        |    output = 3
+        |  } else if 1 == 1 {
+        |    output = 4
+        |  } else {
+        |    output = 65
+        |  }
+        | }
+      """.stripMargin)
+      m.readWord(0xc000) should equal(4)
+  }
 }