pass a temporary arena allocator to the continuation in h_bind

src/hammer.h

@@ -159,8 +159,13 @@ typedef bool (*HPredicate)(HParseResult *p, void* user_data);
  * Type of a parser that depends on the result of a previous parser,
  * used in h_bind(). The void* argument is passed through from h_bind() and can
  * be used to arbitrarily parameterize the function further.
+ *
+ * The HAllocator* argument gives access to temporary memory and is to be used
+ * for any allocations inside the function. Specifically, construction of any
+ * HParsers should use the '__m' combinator variants with the given allocator.
+ * Anything allocated thus will be freed by 'h_bind'.
  */
-typedef HParser* (*HContinuation)(const HParsedToken *x, void *env);
+typedef HParser* (*HContinuation)(HAllocator *mm__, const HParsedToken *x, void *env);
 
 // {{{ Stuff for benchmarking
 typedef struct HParserTestcase_ {

src/parsers/bind.c

@@ -4,8 +4,34 @@ typedef struct {
     const HParser *p;
     HContinuation k;
     void *env;
+    HAllocator *mm__;
 } BindEnv;
 
+// an HAllocator backed by an HArena
+typedef struct {
+    HAllocator allocator;   // inherit  XXX is this the proper way to do it?
+    HArena *arena;
+} ArenaAllocator;
+
+void *aa_alloc(HAllocator *allocator, size_t size)
+{
+    HArena *arena = ((ArenaAllocator *)allocator)->arena;
+    return h_arena_malloc(arena, size);
+}
+
+void *aa_realloc(HAllocator *allocator, void *ptr, size_t size)
+{
+    HArena *arena = ((ArenaAllocator *)allocator)->arena;
+    assert(0);  // XXX realloc for arena allocator
+    return NULL;
+}
+
+void aa_free(HAllocator *allocator, void *ptr)
+{
+    HArena *arena = ((ArenaAllocator *)allocator)->arena;
+    h_arena_free(arena, ptr);
+}
+
 static HParseResult *parse_bind(void *be_, HParseState *state) {
     BindEnv *be = be_;
 
@@ -13,11 +39,20 @@ static HParseResult *parse_bind(void *be_, HParseState *state) {
     if(!res)
         return NULL;
 
-    HParser *kx = be->k(res->ast, be->env);
-    if(!kx)
-        return NULL;
+    // create a temporary arena allocator for the continuation
+    HArena *arena = h_new_arena(be->mm__, 0);
+    ArenaAllocator aa = {{aa_alloc, aa_realloc, aa_free}, arena};
 
-    return h_do_parse(kx, state);
+    HParser *kx = be->k((HAllocator *)&aa, res->ast, be->env);
+    if(!kx) {
+        h_delete_arena(arena);
+        return NULL;
+    }
+
+    res = h_do_parse(kx, state);
+
+    h_delete_arena(arena);
+    return res;
 }
 
 static const HParserVtable bind_vt = {
@@ -40,6 +75,7 @@ HParser *h_bind__m(HAllocator *mm__,
     be->p = p;
     be->k = k;
     be->env = env;
+    be->mm__ = mm__;
 
     return h_new_parser(mm__, &bind_vt, be);
 }

src/t_parser.c

@@ -568,7 +568,7 @@ static void test_permutation(gconstpointer backend) {
   g_check_parse_failed(po2, be, "ccc", 3);
 }
 
-static HParser *f_test_bind(const HParsedToken *p, void *env) {
+static HParser *k_test_bind(HAllocator *mm__, const HParsedToken *p, void *env) {
   uint8_t one = (uintptr_t)env;
   
   assert(p);
@@ -581,17 +581,17 @@ static HParser *f_test_bind(const HParsedToken *p, void *env) {
   }
 
   if(v > 26)
-    return h_nothing_p();	// fail
+    return h_nothing_p__m(mm__);	// fail
   else if(v > 127)
     return NULL;			// equivalent to the above
   else
-    return h_ch(one - 1 + v);
+    return h_ch__m(mm__, one - 1 + v);
 }
 static void test_bind(gconstpointer backend) {
   HParserBackend be = (HParserBackend)GPOINTER_TO_INT(backend);
   const HParser *digit = h_ch_range('0', '9');
   const HParser *nat = h_many1(digit);
-  const HParser *p = h_bind(nat, f_test_bind, (void *)(uintptr_t)'a');
+  const HParser *p = h_bind(nat, k_test_bind, (void *)(uintptr_t)'a');
 
   g_check_parse_match(p, be, "1a", 2, "u0x61");
   g_check_parse_match(p, be, "2b", 2, "u0x62");