Rewrite with working async

lib/rt/core.h

@@ -1,5 +1,6 @@
-// Values and objects: the types that every other part uses, the object
-// header and its tags, the allocator and errors. See docs/model.md
+// Values: the types that every other part uses, the allocator and errors.
+// An object is a struct of its class, which the emitted C defines, and every
+// pointer to one is a real object: undefined and null are values of their own
 #pragma once
 
 #include <stdbool.h>
@@ -12,40 +13,24 @@ typedef struct { char _; } null_t;
 // A string: UTF-16 code units, as JS counts them
 typedef struct jsrt_string *string_t;
 
-// The start of every object: the number of its cell, which tells its struct
-// and, for a fn, its code
-typedef struct { uint32_t cell; } jsrt_header;
-
-// A pointer to an object or a string can also be one of these. NULL is null.
-// They are told apart by their address only
-extern jsrt_header jsrt_undefined_cell, jsrt_absent_cell;
-#define JSRT_UNDEFINED ((void *)&jsrt_undefined_cell)
-#define JSRT_ABSENT ((void *)&jsrt_absent_cell)   // a field that an object lacks
-
-// Whether the objects of each cell are fns, by cell. The emitted C defines it
-extern const bool jsrt_fn_cells[];
-
 // A new heap cell of `size` bytes, all zero
-void *jsrt_alloc(size_t size);
+void *__rt_alloc(size_t size);
 
 // `items`, an array's elements of `size` bytes each, with room for at least
-// `need` of them. `*cap` is the room that it has, and is set to the new room
-void *jsrt_grow(void *items, int32_t *cap, int32_t need, size_t size);
+// `need` of them. `*cap` is the room that it has, and is set to the new room.
+// The new room is all zero
+void *__rt_grow(void *items, int32_t *cap, int32_t need, size_t size);
 
-// Throws a TypeError. Exceptions are not supported yet, so it stops the program
-_Noreturn void jsrt_type_error(void);
-
-// `p`, a pointer to an object or a string. A sentinel for null, undefined or
-// absent throws a TypeError
-void *jsrt_some(void *p);
+// Throws a TypeError, which says `what`. Exceptions are not supported yet, so
+// it stops the program
+_Noreturn void __rt_type_error(const char *what);
 
 #ifdef JSRT_IMPLEMENTATION
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
-jsrt_header jsrt_undefined_cell, jsrt_absent_cell;
-
-void *jsrt_alloc(size_t size) {
+void *__rt_alloc(size_t size) {
     void *p = calloc(1, size);
 
     if (!p) {
@@ -56,7 +41,7 @@ void *jsrt_alloc(size_t size) {
     return p;
 }
 
-void *jsrt_grow(void *items, int32_t *cap, int32_t need, size_t size) {
+void *__rt_grow(void *items, int32_t *cap, int32_t need, size_t size) {
     if (need <= *cap) {
         return items;
     }
@@ -69,21 +54,14 @@ void *jsrt_grow(void *items, int32_t *cap, int32_t need, size_t size) {
         abort();
     }
 
+    memset((char *)items + (size_t)*cap * size, 0, (size_t)(room - *cap) * size);
     *cap = room;
     return items;
 }
 
-_Noreturn void jsrt_type_error(void) {
-    fputs("TypeError\n", stderr);
+_Noreturn void __rt_type_error(const char *what) {
+    fprintf(stderr, "TypeError: %s\n", what);
     exit(1);
 }
 
-void *jsrt_some(void *p) {
-    if (p == NULL || p == JSRT_UNDEFINED || p == JSRT_ABSENT) {
-        jsrt_type_error();
-    }
-
-    return p;
-}
-
 #endif // JSRT_IMPLEMENTATION