flake.nix

@@ -40,6 +40,8 @@
                 pkg-config
                 guile
                 clang-tools # clangd
+                gdb
+                gdbgui
               ];
             };
           };

play/hash.c

@@ -1,11 +1,38 @@
 #include <stdio.h>
+#include <string.h>
 #include "../runtime/gyehoek.h"
 #include "../runtime/weak-set.h"
 
 static int
-symbol_lookup_predicate_fn (SCM sym, void *closure) {
-  SCM other = SCM_PACK_POINTER (closure);
-  return 1;
+symbol_lookup_predicate_fn (SCM sym1, void *closure) {
+  const SCM sym2 = *((SCM*)closure);
+  const int symp1 = SCM_SYMBOLP (sym1);
+  const int symp2 = SCM_SYMBOLP (sym2);
+  // both symbols?
+  if (SCM_SYMBOLP (sym1) && SCM_SYMBOLP (sym2)) {
+    const SCM str1 = SCM_CELL_OBJECT (sym1, 2);
+    const SCM str2 = SCM_CELL_OBJECT (sym2, 2);
+    const size_t len1 = scm_c_string_length (str1);
+    const size_t len2 = scm_c_string_length (str2);
+    // same length?
+    if (len1 == len2) {
+      // same name?
+      const char * const s1 = scm_c_string_chars (str1);
+      const char * const s2 = scm_c_string_chars (str2);
+      return strncmp (s1, s2, len1);
+    }
+  }
+  return 0;
+}
+
+SCM test (SCM set, const char *sym_name, SCM value) {
+  SCM str = scm_from_cstring (sym_name);
+  SCM sym = scm_make_symbol (str, scm_c_hash (str));
+  SCM r = scm_c_weak_set_insert (set, scm_c_hash (str), value,
+                                 symbol_lookup_predicate_fn,
+                                 &sym);
+  printf ("%ld\n", weak_set_count (set));
+  return r;
 }
 
 int main () {
@@ -15,23 +42,7 @@ int main () {
   /* printf ("%ld\n", hash); */
 
   SCM set = scm_c_make_weak_set (31);
-  SCM str = scm_from_cstring ("my-symbol");
-  SCM sym = scm_make_symbol (str, scm_c_hash (str));
-  scm_c_weak_set_insert (set, scm_c_hash (str),
-                         SCM_PACK (SCM_MAKE_SMALL_INT (123)),
-                         symbol_lookup_predicate_fn,
-                         SCM_UNPACK_POINTER (sym));
-  printf ("%ld\n", weak_set_count (set));
-  scm_c_weak_set_insert (set, scm_c_hash (str),
-                         SCM_PACK (SCM_MAKE_SMALL_INT (123)),
-                         symbol_lookup_predicate_fn,
-                         SCM_UNPACK_POINTER (sym));
-  printf ("%ld\n", weak_set_count (set));
-  SCM str2 = scm_from_cstring ("my-symbol2");
-  SCM sym2 = scm_make_symbol (str2, scm_c_hash (str2));
-  scm_c_weak_set_insert (set, scm_c_hash (str2),
-                         SCM_PACK (SCM_MAKE_SMALL_INT (456)),
-                         symbol_lookup_predicate_fn,
-                         SCM_UNPACK_POINTER (sym2));
-  printf ("%ld\n", weak_set_count (set));
+  test (set, "my-symbol", SCM_PACK (SCM_MAKE_SMALL_INT (123)));
+  test (set, "my-symbol", SCM_PACK (SCM_MAKE_SMALL_INT (123)));
+  test (set, "my-symbol2", SCM_PACK (SCM_MAKE_SMALL_INT (456)));
 }

runtime/gyehoek.h

@@ -80,7 +80,18 @@ extern const long scm_tc7_weak_set;
 extern const long scm_tc7_symbol;
 extern const long scm_tc7_string;
 
+
+/// Strings
+
 #define SCM_STRINGP(x) (SCM_TYP7 (x) == scm_tc7_string)
+
+size_t scm_c_string_length (SCM str);
+
+const char *scm_c_string_chars (SCM str);
+
+
+/// Symbols
+
 #define SCM_SYMBOLP(x) (SCM_TYP7 (x) == scm_tc7_symbol)
 
 

runtime/weak-set.c

@@ -92,6 +92,7 @@ find_bucket (scm_t_weak_set *set, unsigned long hash,
              && pred (SCM_PACK (set->entries[p].key), closure)) {
     return SCM_PACK (set->entries[p].key);
   } else {
+    /* i have faith in gcc's TCO. */
     return find_bucket (set, hash, key, pred, closure,
                         (p + 1) % set->size);
   }
@@ -101,7 +102,7 @@ find_bucket (scm_t_weak_set *set, unsigned long hash,
 
 SCM scm_c_weak_set_insert (SCM set, unsigned long hash,
                            SCM key, scm_t_set_predicate_fn pred,
-                           void* closure) {
+                           void *closure) {
   scm_t_weak_set *s = SCM_WEAK_SET (set);
   unsigned long size = s->size;