HAS_ABSTRACTLIST_PROC

5 files changed, 38 insertions, 31 deletions

diff --git a/generic/tclArithSeries.c b/generic/tclArithSeries.c
index 34c0dd1..70bbb1b 100755
--- a/generic/tclArithSeries.c
+++ b/generic/tclArithSeries.c
@@ -76,8 +76,9 @@ const TclObjTypeWithAbstractList tclArithSeriesType = {
     DupArithSeriesInternalRep,		/* dupIntRepProc */
     UpdateStringOfArithSeries,		/* updateStringProc */
     SetArithSeriesFromAny,		/* setFromAnyProc */
-    TCL_OBJTYPE_V0_1},
+    TCL_OBJTYPE_V0_1(
 	TclArithSeriesObjLength
+    )
 };
 
 /*
diff --git a/generic/tclInt.h b/generic/tclInt.h
index a58c401..0ff0d8e 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -1076,14 +1076,6 @@ typedef struct ActiveInterpTrace {
 				 * in reverse order. */
 } ActiveInterpTrace;
 
-
-#define TCL_OBJTYPE_V0_1 ((size_t)1) /* For internal core use only */
-
-typedef struct {  /* For internal core use only */
-    Tcl_ObjType objType;
-    unsigned long long (*lengthProc)(Tcl_Obj *obj);
-} TclObjTypeWithAbstractList;
-
 /*
  * Flag values designating types of execution traces. See tclTrace.c for
  * related flag values.
@@ -1099,6 +1091,16 @@ typedef struct {  /* For internal core use only */
 #define TCL_TRACE_ENTER_EXEC	1
 #define TCL_TRACE_LEAVE_EXEC	2
 
+typedef struct {  /* For internal core use only */
+    Tcl_ObjType objType;
+    unsigned long long (*lengthProc)(Tcl_Obj *obj);
+} TclObjTypeWithAbstractList;
+#define TCL_OBJTYPE_V0_1(lengthProc) (sizeof(TclObjTypeWithAbstractList)) \
+	}, lengthProc /* For internal core use only */
+#define HAS_ABSTRACTLIST_PROC(objPtr, proc) (objPtr->typePtr \
+	&& (objPtr->typePtr->version > offsetof(TclObjTypeWithAbstractList, proc)) \
+	&& (((const TclObjTypeWithAbstractList *)objPtr->typePtr)->proc))
+
 /*
  * The structure below defines an entry in the assocData hash table which is
  * associated with an interpreter. The entry contains a pointer to a function
diff --git a/generic/tclListObj.c b/generic/tclListObj.c
index 4a5b3ae..565872e 100644
--- a/generic/tclListObj.c
+++ b/generic/tclListObj.c
@@ -158,8 +158,9 @@ const TclObjTypeWithAbstractList tclListType = {
     DupListInternalRep,		/* dupIntRepProc */
     UpdateStringOfList,		/* updateStringProc */
     SetListFromAny,		/* setFromAnyProc */
-    TCL_OBJTYPE_V0_1},
-    ListLength
+    TCL_OBJTYPE_V0_1(
+	ListLength
+    )
 };
 
 /* Macros to manipulate the List internal rep */
@@ -1994,19 +1995,17 @@ Tcl_ListObjLength(
     Tcl_Obj *listObj,	/* List object whose #elements to return. */
     Tcl_Size *lenPtr)	/* The resulting int is stored here. */
 {
-    if (listObj->typePtr && (listObj->typePtr->version == TCL_OBJTYPE_V0_1)) {
+    if (HAS_ABSTRACTLIST_PROC(listObj, lengthProc)) {
 	const TclObjTypeWithAbstractList *objType =  (const TclObjTypeWithAbstractList *)listObj->typePtr;
-	if (objType->lengthProc) {
-	    unsigned long long len = objType->lengthProc(listObj);
-	    if (len >= TCL_INDEX_NONE) {
-		if (interp) {
-			Tcl_AppendResult(interp, "List too large");
-		}
-		return TCL_ERROR;
+	unsigned long long len = objType->lengthProc(listObj);
+	if (len >= TCL_INDEX_NONE) {
+	    if (interp) {
+		    Tcl_AppendResult(interp, "List too large");
 	    }
-	    *lenPtr = len;
-	    return TCL_OK;
+	    return TCL_ERROR;
 	}
+	*lenPtr = len;
+	return TCL_OK;
     }
 
     /*
diff --git a/generic/tclObj.c b/generic/tclObj.c
index 5e3f4f1..ca7861f 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -233,8 +233,9 @@ const TclObjTypeWithAbstractList tclBooleanType= {
     NULL,			/* dupIntRepProc */
     NULL,			/* updateStringProc */
     TclSetBooleanFromAny,		/* setFromAnyProc */
-    TCL_OBJTYPE_V0_1},
-    LengthOne
+    TCL_OBJTYPE_V0_1(
+	LengthOne
+    )
 };
 const TclObjTypeWithAbstractList tclDoubleType= {
     {"double",			/* name */
@@ -242,8 +243,9 @@ const TclObjTypeWithAbstractList tclDoubleType= {
     NULL,			/* dupIntRepProc */
     UpdateStringOfDouble,	/* updateStringProc */
     SetDoubleFromAny,		/* setFromAnyProc */
-    TCL_OBJTYPE_V0_1},
-    LengthOne
+    TCL_OBJTYPE_V0_1(
+	LengthOne
+    )
 };
 const TclObjTypeWithAbstractList tclIntType = {
     {"int",			/* name */
@@ -251,8 +253,9 @@ const TclObjTypeWithAbstractList tclIntType = {
     NULL,			/* dupIntRepProc */
     UpdateStringOfInt,		/* updateStringProc */
     SetIntFromAny,		/* setFromAnyProc */
-    TCL_OBJTYPE_V0_1},
-    LengthOne
+    TCL_OBJTYPE_V0_1(
+	LengthOne
+    )
 };
 const TclObjTypeWithAbstractList tclBignumType = {
     {"bignum",			/* name */
@@ -260,8 +263,9 @@ const TclObjTypeWithAbstractList tclBignumType = {
     DupBignum,			/* dupIntRepProc */
     UpdateStringOfBignum,	/* updateStringProc */
     NULL,			/* setFromAnyProc */
-    TCL_OBJTYPE_V0_1},
-    LengthOne
+    TCL_OBJTYPE_V0_1(
+	LengthOne
+    )
 };
 
 /*
diff --git a/generic/tclUtil.c b/generic/tclUtil.c
index b23d134..58fb1e4 100644
--- a/generic/tclUtil.c
+++ b/generic/tclUtil.c
@@ -130,8 +130,9 @@ static const TclObjTypeWithAbstractList endOffsetType = {
     NULL,				/* dupIntRepProc */
     NULL,				/* updateStringProc */
     NULL,				/* setFromAnyProc */
-    TCL_OBJTYPE_V0_1},
-    LengthOne
+    TCL_OBJTYPE_V0_1(
+	LengthOne
+    )
 };
 
 /*