Changes to how uncaught exceptions are handled.

- Don't clear the HAS_EXCEPTION bit.
- Reuse CLEAN_OUTPUT to disable printing the exception.
- Don't reset the stack, repls should do that _on every call_.
- Fix up sandbox and simple-repl.h, they don't need to do that silly stack thing to handle exceptions themselves.

src/kuroko.c

@@ -688,8 +688,8 @@ _finishArgs:
 					} else {
 						fprintf(stdout, formatStr, AS_CSTRING(result));
 					}
-					krk_resetStack();
 				}
+				krk_resetStack();
 				free(allData);
 			}
 
@@ -697,7 +697,8 @@ _finishArgs:
 		}
 	} else {
 		krk_startModule("__main__");
-		result = krk_runfile(argv[optind],1,"__main__",argv[optind]);
+		result = krk_runfile(argv[optind],0,"__main__",argv[optind]);
+		if (IS_NONE(result) && krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION) result = INTEGER_VAL(1);
 	}
 
 	krk_freeVM();

src/vm.c

@@ -1416,8 +1416,7 @@ static int handleException() {
 			 * VM stack state. It should still be safe to execute more code after
 			 * this reset, so the repl can throw errors and keep accepting new lines.
 			 */
-			krk_dumpTraceback();
-			krk_resetStack();
+			if (!(vm.globalFlags & KRK_GLOBAL_CLEAN_OUTPUT)) krk_dumpTraceback();
 			krk_currentThread.frameCount = 0;
 		}
 		/* If exitSlot was not 0, there was an exception during a call to runNext();

tools/sandbox.c

@@ -7,18 +7,18 @@
 #include "simple-repl.h"
 
 int main(int argc, char * argv[]) {
-	krk_initVM(0);
+	/* Initialize VM with traceback printing disabled (we'll print them ourselves) */
+	krk_initVM(KRK_GLOBAL_CLEAN_OUTPUT);
 
+	/* Disable imports, ensure the system module is inaccessible, disable print */
 	krk_tableDelete(&vm.system->fields, OBJECT_VAL(S("module_paths")));
 	krk_tableDelete(&vm.modules, OBJECT_VAL(S("kuroko")));
 	krk_tableDelete(&vm.builtins->fields, OBJECT_VAL(S("print")));
 
-	/* Don't automatically dump tracebacks. */
-	krk_resetStack();
-	krk_push(NONE_VAL());
-	krk_currentThread.frames[0].outSlots = 1;
-
+	/* Set up our module context. */
 	krk_startModule("<module>");
+
+	/* Attach a docstring so that we can interpret strings */
 	krk_attachNamedValue(&krk_currentThread.module->fields,"__doc__", NONE_VAL());
 
 	int retval = 0;

tools/simple-repl.h

@@ -115,10 +115,10 @@ static int runSimpleRepl(void) {
 				} else {
 					fprintf(stdout, formatStr, AS_CSTRING(result));
 				}
-				krk_resetStack();
 			} else if (krk_currentThread.flags & KRK_THREAD_HAS_EXCEPTION) {
 				krk_dumpTraceback();
 			}
+			krk_resetStack();
 			free(allData);
 		}