3 files changed, 21 insertions, 10 deletions

diff --git a/pit/src/runtime/dump.c b/pit/src/runtime/dump.c
index 734c379..52441a8 100644
--- a/pit/src/runtime/dump.c
+++ b/pit/src/runtime/dump.c
@@ -111,8 +111,8 @@ pit_dump_condition pit_dump_with_callback(
                         if (readable) { buf[i++] = '"'; }
                         i64 maxlen = len - i;
                         for (i64 j = 0; i < maxlen && j < h->in.bytes.len;) {
-                            bool needs_backslash =
-                                (i == 0 || buf[i - 1] != '\\')
+                            bool needs_backslash = readable
+                                && (i == 0 || buf[i - 1] != '\\')
                                 && (h->in.bytes.data[j] == '\\' || h->in.bytes.data[j] == '"');
                             if (needs_backslash) {
                                 buf[i++] = '\\';
@@ -192,11 +192,17 @@ i64 pit_dump_printf_callback(va_list ap, char *buf, size_t len, void *data) {
     pit_value arg = va_arg(ap, pit_value);
     return pit_dump(rt, buf, (i64) len, arg, false);
 }
+i64 pit_dump_readable_printf_callback(va_list ap, char *buf, size_t len, void *data) {
+    pit_runtime *rt = (pit_runtime *) data;
+    pit_value arg = va_arg(ap, pit_value);
+    return pit_dump(rt, buf, (i64) len, arg, true);
+}
 i64 pit_vsnprintf(pit_runtime *rt, char *buf, i64 len, char *format, va_list ap) {
     if (len == 0) return 0;
-    pit_printf_handler h[1];
+    pit_printf_handler h[2];
     h[0].specifier = 'v'; h[0].callback = pit_dump_printf_callback;
-    i64 ret = pit_vsnprintf_helper(buf, (size_t) (len - 1), format, ap, h, 1, rt);
+    h[1].specifier = 'V'; h[1].callback = pit_dump_readable_printf_callback;
+    i64 ret = pit_vsnprintf_helper(buf, (size_t) (len - 1), format, ap, h, 2, rt);
     buf[ret] = 0;
     return ret;
 }
diff --git a/pit/src/runtime/eval.c b/pit/src/runtime/eval.c
index a2ed166..3cd1c1f 100644
--- a/pit/src/runtime/eval.c
+++ b/pit/src/runtime/eval.c
@@ -152,13 +152,14 @@ static pit_value vm_erase_empty(pit_runtime *rt, bool unbind) {
 /* run one instruction of the VM */
 bool pit_vm_run_one(pit_runtime *rt) {
     vm_erase_empty(rt, true);
-    if (rt->callstack->next < 1 || rt->error != PIT_NIL) return false;
+    if (rt->callstack->next < 1) return false;
+    if (rt->error != PIT_NIL) goto err;
     pit_callstack_entry *ent = pit_vec_get(pit_callstack_entry)(rt->callstack, rt->callstack->next - 1);
-    if (ent == NULL) { pit_error(rt, "malformed call stack"); return false; }
-    if (rt->fuel == 0) { pit_error(rt, "out of fuel"); return false; }
+    if (ent == NULL) { pit_error(rt, "malformed call stack"); goto err; }
+    if (rt->fuel == 0) { pit_error(rt, "out of fuel"); goto err; }
     rt->fuel -= 1;
     pit_value ins = pit_value_cons_car(rt, ent->code);
-    if (ins == PIT_NIL) { pit_error(rt, "malformed vm instruction: %v %v", ins); return false; }
+    if (ins == PIT_NIL) { pit_error(rt, "malformed vm instruction: %v %v", ins); goto err; }
     ent->code = pit_value_cons_cdr(rt, ent->code);
     pit_value op = pit_value_cons_car(rt, ins);
     if (pit_symtab_symbol_name_match_cstr(rt, op, "literal")) {
@@ -196,13 +197,17 @@ bool pit_vm_run_one(pit_runtime *rt) {
         pit_value args = PIT_NIL;
         while (arity-- > 0) args = pit_value_cons(rt, vm_pop(rt), args);
         pit_value bindings = vm_erase_empty(rt, false);
-        if (!vm_call(rt, f, args, bindings)) return false;
+        if (!vm_call(rt, f, args, bindings)) goto err;
     } else {
         pit_error(rt, "unrecognized vm instruction: %v", ins);
         return false;
     }
     vm_erase_empty(rt, true);
     return true;
+err:
+    rt->result_stack->next = 0;
+    rt->callstack->next = 0;
+    return false;
 }
 
 /* run the VM until evaluation of this code finishes, returning the result */
diff --git a/pit/src/runtime/value/small.c b/pit/src/runtime/value/small.c
index e0bdf0a..7b9057e 100644
--- a/pit/src/runtime/value/small.c
+++ b/pit/src/runtime/value/small.c
@@ -23,7 +23,7 @@ pit_value pit_value_double_new(pit_runtime *rt, double d) {
 
 i64 pit_value_as_integer(pit_runtime *rt, pit_value v) {
     if (pit_value_sort(v) != PIT_VALUE_SORT_INTEGER) {
-        pit_error(rt, "invalid use of value %v as integer", v);
+        pit_error(rt, "invalid use of value %V as integer", v);
         return -1;
     }
     u64 lo = pit_value_data(v);