introduce pic_invalid_value

extlib/benz/debug.c

@@ -35,7 +35,7 @@ pic_get_backtrace(pic_state *pic)
 void
 pic_print_backtrace(pic_state *pic, xFILE *file)
 {
-  assert(! pic_undef_p(pic->err));
+  assert(! pic_invalid_p(pic->err));
 
   if (! pic_error_p(pic->err)) {
     xfprintf(file, "raise: ");

extlib/benz/error.c

@@ -52,7 +52,7 @@ pic_errmsg(pic_state *pic)
 {
   pic_str *str;
 
-  assert(! pic_undef_p(pic->err));
+  assert(! pic_invalid_p(pic->err));
 
   if (! pic_error_p(pic->err)) {
     str = pic_format(pic, "~s", pic->err);

extlib/benz/gc.c

@@ -482,6 +482,7 @@ gc_mark_object(pic_state *pic, struct pic_object *obj)
   case PIC_TT_CHAR:
   case PIC_TT_EOF:
   case PIC_TT_UNDEF:
+  case PIC_TT_INVALID:
     pic_panic(pic, "logic flaw");
   }
 }
@@ -694,6 +695,7 @@ gc_finalize_object(pic_state *pic, struct pic_object *obj)
   case PIC_TT_CHAR:
   case PIC_TT_EOF:
   case PIC_TT_UNDEF:
+  case PIC_TT_INVALID:
     pic_panic(pic, "logic flaw");
   }
 }

extlib/benz/include/picrin/value.h

@@ -10,8 +10,8 @@ extern "C" {
 #endif
 
 /**
- * `undef` values never seen from user-end: that is,
+ * `invalid` value will never be seen from user-end:
- *  it's used only for repsenting internal special state
+ *  it is only used for repsenting internal special state
  */
 
 enum pic_vtype {
@@ -19,6 +19,7 @@ enum pic_vtype {
   PIC_VTYPE_TRUE,
   PIC_VTYPE_FALSE,
   PIC_VTYPE_UNDEF,
+  PIC_VTYPE_INVALID,
 #if PIC_ENABLE_FLOAT
   PIC_VTYPE_FLOAT,
 #endif
@@ -146,6 +147,7 @@ enum pic_tt {
   PIC_TT_CHAR,
   PIC_TT_EOF,
   PIC_TT_UNDEF,
+  PIC_TT_INVALID,
   /* heap */
   PIC_TT_SYMBOL,
   PIC_TT_PAIR,
@@ -196,6 +198,7 @@ typedef struct pic_blob pic_blob;
 #define pic_true_p(v) (pic_vtype(v) == PIC_VTYPE_TRUE)
 #define pic_false_p(v) (pic_vtype(v) == PIC_VTYPE_FALSE)
 #define pic_undef_p(v) (pic_vtype(v) == PIC_VTYPE_UNDEF)
+#define pic_invalid_p(v) (pic_vtype(v) == PIC_VTYPE_INVALID)
 #define pic_float_p(v) (pic_vtype(v) == PIC_VTYPE_FLOAT)
 #define pic_int_p(v) (pic_vtype(v) == PIC_VTYPE_INT)
 #define pic_char_p(v) (pic_vtype(v) == PIC_VTYPE_CHAR)
@@ -231,6 +234,7 @@ PIC_INLINE pic_value pic_true_value();
 PIC_INLINE pic_value pic_false_value();
 PIC_INLINE pic_value pic_bool_value(bool);
 PIC_INLINE pic_value pic_undef_value();
+PIC_INLINE pic_value pic_invalid_value();
 PIC_INLINE pic_value pic_obj_value(void *);
 #if PIC_ENABLE_FLOAT
 PIC_INLINE pic_value pic_float_value(double);
@@ -255,6 +259,8 @@ pic_type(pic_value v)
     return PIC_TT_BOOL;
   case PIC_VTYPE_UNDEF:
     return PIC_TT_UNDEF;
+  case PIC_VTYPE_INVALID:
+    return PIC_TT_INVALID;
 #if PIC_ENABLE_FLOAT
   case PIC_VTYPE_FLOAT:
     return PIC_TT_FLOAT;
@@ -294,6 +300,8 @@ pic_type_repr(enum pic_tt tt)
     return "eof";
   case PIC_TT_UNDEF:
     return "undef";
+  case PIC_TT_INVALID:
+    return "invalid";
   case PIC_TT_PAIR:
     return "pair";
   case PIC_TT_STRING:
@@ -500,6 +508,15 @@ pic_undef_value()
   return v;
 }
 
+PIC_INLINE pic_value
+pic_invalid_value()
+{
+  pic_value v;
+
+  pic_init_value(v, PIC_VTYPE_INVALID);
+  return v;
+}
+
 PIC_INLINE pic_value
 pic_none_value()
 {

extlib/benz/read.c

@@ -92,7 +92,7 @@ read_comment(pic_state PIC_UNUSED(*pic), struct pic_port *port, int c)
     c = next(port);
   } while (! (c == EOF || c == '\n'));
 
-  return pic_undef_value();
+  return pic_invalid_value();
 }
 
 static pic_value
@@ -114,7 +114,7 @@ read_block_comment(pic_state PIC_UNUSED(*pic), struct pic_port *port, int PIC_UN
     }
   }
 
-  return pic_undef_value();
+  return pic_invalid_value();
 }
 
 static pic_value
@@ -122,7 +122,7 @@ read_datum_comment(pic_state *pic, struct pic_port *port, int PIC_UNUSED(c))
 {
   read(pic, port, next(port));
 
-  return pic_undef_value();
+  return pic_invalid_value();
 }
 
 static pic_value
@@ -132,13 +132,13 @@ read_directive(pic_state *pic, struct pic_port *port, int c)
   case 'n':
     if (expect(port, "no-fold-case")) {
       pic->reader->typecase = PIC_CASE_DEFAULT;
-      return pic_undef_value();
+      return pic_invalid_value();
     }
     break;
   case 'f':
     if (expect(port, "fold-case")) {
       pic->reader->typecase = PIC_CASE_FOLD;
-      return pic_undef_value();
+      return pic_invalid_value();
     }
     break;
   }
@@ -578,7 +578,7 @@ read_pair(pic_state *pic, struct pic_port *port, int c)
 
   closing:
     if ((c = skip(port, ' ')) != tCLOSE) {
-      if (pic_undef_p(read_nullable(pic, port, c))) {
+      if (pic_invalid_p(read_nullable(pic, port, c))) {
         goto closing;
       }
       read_error(pic, "unmatched parenthesis");
@@ -588,7 +588,7 @@ read_pair(pic_state *pic, struct pic_port *port, int c)
   else {
     car = read_nullable(pic, port, c);
 
-    if (pic_undef_p(car)) {
+    if (pic_invalid_p(car)) {
       goto retry;
     }
 
@@ -742,7 +742,7 @@ read(pic_state *pic, struct pic_port *port, int c)
  retry:
   val = read_nullable(pic, port, c);
 
-  if (pic_undef_p(val)) {
+  if (pic_invalid_p(val)) {
     c = next(port);
     goto retry;
   }
@@ -840,7 +840,7 @@ pic_read(pic_state *pic, struct pic_port *port)
 
   val = read_nullable(pic, port, c);
 
-  if (pic_undef_p(val)) {
+  if (pic_invalid_p(val)) {
     c = next(port);
     goto retry;
   }

extlib/benz/state.c

@@ -223,7 +223,7 @@ pic_open(int argc, char *argv[], char **envp, pic_allocf allocf)
   pic->lib = NULL;
 
   /* raised error object */
-  pic->err = pic_undef_value();
+  pic->err = pic_invalid_value();
 
   /* standard ports */
   pic->xSTDIN = NULL;
@@ -402,7 +402,7 @@ pic_close(pic_state *pic)
   pic->ci = pic->cibase;
   pic->xp = pic->xpbase;
   pic->arena_idx = 0;
-  pic->err = pic_undef_value();
+  pic->err = pic_invalid_value();
   pic->globals = NULL;
   pic->macros = NULL;
   xh_clear(&pic->syms);