renaming symbol accessors to lsymbol, and clarifying the use of SEXP_USE_SAFE_ACCESSORS

include/chibi/features.h

@@ -86,6 +86,21 @@
 /* uncomment this to add very verbose debugging stats to the native GC */
 /* #define SEXP_USE_DEBUG_GC 1 */
 
+/* uncomment this to enable "safe" field accessors for primitive types */
+/*   The sexp union type fields are abstracted away with macros of the */
+/*   form sexp_<type>_<field>(<obj>), however these are just convenience */
+/*   macros equivalent to directly accessing the union field, and will */
+/*   return incorrect results (or segfault) if <obj> isn't of the correct */
+/*   <type>.  Thus you're required to check the types manually before */
+/*   accessing them.  However, to detect errors earlier you can enable */
+/*   SEXP_USE_SAFE_ACCESSORS, and on invalid accesses chibi will print */
+/*   a friendly error message and immediately segfault itself so you */
+/*   can see where the invalid access was made. */
+/*   Note this is only intended for debugging, and mostly for user code. */
+/*   If you want to build chibi itself with this option, compilation */
+/*   may be very slow and using CFLAGS=-O0 is recommended. */
+/* #define SEXP_USE_SAFE_ACCESSORS 1 */
+
 /* uncomment this to make the heap common to all contexts */
 /*   By default separate contexts can have separate heaps, */
 /*   and are thus thread-safe and independant. */

include/chibi/sexp.h

@@ -845,8 +845,8 @@ SEXP_API sexp sexp_make_unsigned_integer(sexp ctx, sexp_luint_t x);
 #define sexp_string_ref(x, i)    (sexp_make_character((unsigned char)sexp_string_data(x)[sexp_unbox_fixnum(i)]))
 #define sexp_string_set(x, i, v) (sexp_string_data(x)[sexp_unbox_fixnum(i)] = sexp_unbox_character(v))
 
-#define sexp_symbol_data(x)    (sexp_field(x, symbol, SEXP_SYMBOL, data))
+#define sexp_lsymbol_data(x)   (sexp_field(x, symbol, SEXP_SYMBOL, data))
-#define sexp_symbol_length(x)  (sexp_field(x, symbol, SEXP_SYMBOL, length))
+#define sexp_lsymbol_length(x) (sexp_field(x, symbol, SEXP_SYMBOL, length))
 
 #define sexp_port_stream(p)     (sexp_pred_field(p, port, sexp_portp, stream))
 #define sexp_port_name(p)       (sexp_pred_field(p, port, sexp_portp, name))

lib/srfi/95/qsort.c

@@ -82,7 +82,7 @@ static int sexp_object_compare (sexp ctx, sexp a, sexp b) {
           res = strcmp(sexp_string_data(a), sexp_string_data(b));
           break;
         case SEXP_SYMBOL:
-          res = strcmp(sexp_symbol_data(a), sexp_symbol_data(b));
+          res = strcmp(sexp_lsymbol_data(a), sexp_lsymbol_data(b));
           break;
         default:
           res = 0;
@@ -91,7 +91,7 @@ static int sexp_object_compare (sexp ctx, sexp a, sexp b) {
       }
 #if SEXP_USE_HUFF_SYMS
     } else if (sexp_lsymbolp(a) && sexp_isymbolp(b)) {
-      res = strcmp(sexp_symbol_data(a),
+      res = strcmp(sexp_lsymbol_data(a),
 		   sexp_string_data(sexp_write_to_string(ctx, b)));
 #endif
     } else {
@@ -101,7 +101,7 @@ static int sexp_object_compare (sexp ctx, sexp a, sexp b) {
 #if SEXP_USE_HUFF_SYMS
     if (sexp_isymbolp(a) && sexp_lsymbolp(b))
       res = strcmp(sexp_string_data(sexp_write_to_string(ctx, a)),
-		   sexp_symbol_data(b));
+		   sexp_lsymbol_data(b));
     else
 #endif
       res = -1;

sexp.c

@@ -1058,8 +1058,8 @@ sexp sexp_intern(sexp ctx, const char *str, sexp_sint_t len) {
   bucket = (sexp_string_hash(p, len-i, res) % SEXP_SYMBOL_TABLE_SIZE);
 #endif
   for (ls=sexp_context_symbols(ctx)[bucket]; sexp_pairp(ls); ls=sexp_cdr(ls))
-    if ((sexp_symbol_length(tmp=sexp_car(ls)) == len)
+    if ((sexp_lsymbol_length(tmp=sexp_car(ls)) == len)
-        && ! strncmp(str, sexp_symbol_data(tmp), len))
+        && ! strncmp(str, sexp_lsymbol_data(tmp), len))
       return sexp_car(ls);
 
   /* not found, make a new symbol */
@@ -1565,12 +1565,12 @@ sexp sexp_write_one (sexp ctx, sexp obj, sexp out) {
       sexp_write_char(ctx, '"', out);
       break;
     case SEXP_SYMBOL:
-      str = sexp_symbol_data(obj);
+      str = sexp_lsymbol_data(obj);
-      c = sexp_symbol_length(obj) > 0 ? EOF : '|';
+      c = sexp_lsymbol_length(obj) > 0 ? EOF : '|';
-      for (i=sexp_symbol_length(obj)-1; i>=0; i--)
+      for (i=sexp_lsymbol_length(obj)-1; i>=0; i--)
         if (str[i] <= ' ' || str[i] == '\\' || is_separator(str[i])) c = '|';
       if (c!=EOF) sexp_write_char(ctx, c, out);
-      for (i=sexp_symbol_length(obj); i>0; str++, i--) {
+      for (i=sexp_lsymbol_length(obj); i>0; str++, i--) {
         if (str[0] == '\\') sexp_write_char(ctx, '\\', out);
         sexp_write_char(ctx, str[0], out);
       }
@@ -2663,7 +2663,7 @@ sexp sexp_symbol_to_string_op (sexp ctx, sexp self, sexp_sint_t n, sexp sym) {
   if (sexp_isymbolp(sym)) return sexp_write_to_string(ctx, sym);
 #endif
   sexp_assert_type(ctx, sexp_lsymbolp, SEXP_SYMBOL, sym);
-  return sexp_c_string(ctx, sexp_symbol_data(sym), sexp_symbol_length(sym));
+  return sexp_c_string(ctx, sexp_lsymbol_data(sym), sexp_lsymbol_length(sym));
 }
 
 void sexp_init (void) {