New partly working cell model

lib/rt/any.h

@@ -150,7 +150,7 @@ bool __any_is_string(any_t a) { return a.kind == JSRT_KIND_STRING; }
 bool __any_is_object(any_t a) { return a.kind == JSRT_KIND_OBJECT; }
 
 bool __any_is_function(any_t a) {
-    return a.kind == JSRT_KIND_OBJECT && jsrt_fn_sites[((jsrt_header *)a.as.o)->site];
+    return a.kind == JSRT_KIND_OBJECT && jsrt_fn_cells[((jsrt_header *)a.as.o)->cell];
 }
 
 // ── any: abstract operations ──

lib/rt/core.h

@@ -12,23 +12,18 @@ 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 site that created it, which tells its shape
+// The start of every object: the number of its cell, which tells its struct
 // and, for a fn, its code
-typedef struct { uint32_t site; } jsrt_header;
+typedef struct { uint32_t cell; } jsrt_header;
 
-// The sites below 3 are tags. An object of a value shape is a struct, not a
-// pointer, so its header tells if it is undefined, null or absent instead
-#define JSRT_SITE_UNDEFINED 0
-#define JSRT_SITE_NULL 1
-#define JSRT_SITE_ABSENT 2
-
-// A pointer to an object or a string can also be one of these. NULL is null
+// 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 site are fns, by site. The emitted C defines it
-extern const bool jsrt_fn_sites[];
+// 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);
@@ -48,8 +43,7 @@ void *jsrt_some(void *p);
 #include <stdio.h>
 #include <stdlib.h>
 
-jsrt_header jsrt_undefined_cell = { JSRT_SITE_UNDEFINED };
-jsrt_header jsrt_absent_cell = { JSRT_SITE_ABSENT };
+jsrt_header jsrt_undefined_cell, jsrt_absent_cell;
 
 void *jsrt_alloc(size_t size) {
     void *p = calloc(1, size);