From 2f18ecbaa15f50459ecfd864495b953a23191732 Mon Sep 17 00:00:00 2001
From: "K. Lange" <klange@toaruos.org>
Date: Fri, 29 Jul 2022 19:33:31 +0900
Subject: [PATCH] Support 'else' block on 'try'

---
 src/compiler.c              | 15 ++++++++++++---
 test/testTryElse.krk        | 26 ++++++++++++++++++++++++++
 test/testTryElse.krk.expect |  8 ++++++++
 3 files changed, 46 insertions(+), 3 deletions(-)
 create mode 100644 test/testTryElse.krk
 create mode 100644 test/testTryElse.krk.expect

diff --git a/src/compiler.c b/src/compiler.c
index 46054357..cfa3e94a 100644
--- a/src/compiler.c
+++ b/src/compiler.c
@@ -2205,6 +2205,7 @@ static void tryStatement(struct GlobalState * state) {
 	exitJumpOffsets[0] = emitJump(OP_JUMP);
 	patchJump(tryJump);
 
+	int firstJump = 0;
 	int nextJump = -1;
 
 _anotherExcept:
@@ -2215,7 +2216,7 @@ static void tryStatement(struct GlobalState * state) {
 			previous = state->parser.previous;
 			advance();
 		}
-		if (match(TOKEN_EXCEPT)) {
+		if (exitJumps && !firstJump && match(TOKEN_EXCEPT)) {
 			if (nextJump != -1) {
 				patchJump(nextJump);
 				emitByte(OP_POP);
@@ -2254,10 +2255,18 @@ static void tryStatement(struct GlobalState * state) {
 				return;
 			}
 
+			goto _anotherExcept;
+		} else if (firstJump != 1 && match(TOKEN_ELSE)) {
+			consume(TOKEN_COLON, "Expected ':' after 'else'.");
+			patchJump(exitJumpOffsets[0]);
+			firstJump = 1;
+			beginScope(state);
+			block(state, blockWidth, "else");
+			endScope(state);
 			goto _anotherExcept;
 		} else if (match(TOKEN_FINALLY)) {
 			consume(TOKEN_COLON, "Expected ':' after 'finally'.");
-			for (int i = 0; i < exitJumps; ++i) {
+			for (int i = firstJump; i < exitJumps; ++i) {
 				patchJump(exitJumpOffsets[i]);
 			}
 			size_t nameInd = renameLocal(state, exceptionObject, syntheticToken("__tmp"));
@@ -2285,7 +2294,7 @@ static void tryStatement(struct GlobalState * state) {
 		}
 	}
 
-	for (int i = 0; i < exitJumps; ++i) {
+	for (int i = firstJump; i < exitJumps; ++i) {
 		patchJump(exitJumpOffsets[i]);
 	}
 
diff --git a/test/testTryElse.krk b/test/testTryElse.krk
new file mode 100644
index 00000000..bc618a28
--- /dev/null
+++ b/test/testTryElse.krk
@@ -0,0 +1,26 @@
+try:
+    print('totally fine')
+except:
+    print('impossible!')
+else:
+    print('good to go')
+finally:
+    print('then the finally')
+
+try:
+    print('totally fine')
+except:
+    print('impossible!')
+else:
+    print('good to go')
+
+try:
+    print('in the try')
+    raise ValueError()
+    print('oh no, fail')
+except:
+    print('does the except')
+else:
+    print('should not happen, fail')
+finally:
+    print('does the finally')
diff --git a/test/testTryElse.krk.expect b/test/testTryElse.krk.expect
new file mode 100644
index 00000000..5063ceec
--- /dev/null
+++ b/test/testTryElse.krk.expect
@@ -0,0 +1,8 @@
+totally fine
+good to go
+then the finally
+totally fine
+good to go
+in the try
+does the except
+does the finally