Fix for TF_Generator

We can't add new TF types in the middle of the tformTag enum, as the
hashcode of TF_Map (and others) may change.  This then breaks the
fricas interop code.

Author: pbroadbery

aldor/aldor/src/tform.c

@@ -8489,7 +8489,6 @@ struct tform_info tformInfoTable[] = {
 	{TF_Enumerate,	"Enumeration",  "Enumeration",  0, 1},
 	{TF_Forward,	"Forward",      "Forward",      0, 1},
 	{TF_Generator,	"Generator",    "Generator",    0, 1},
-	{TF_XGenerator,	"XGenerator",   "XGenerator",    0, 1},
 	{TF_If,		"If",           "If",           0, 3},
 	{TF_Instance,	"Instance",     "Instance",     0, 2},
 	{TF_Join,	"Join",         "Join",         0, TF_NARY},
@@ -8510,6 +8509,7 @@ struct tform_info tformInfoTable[] = {
 	{TF_Variable,	"Variable",     "Variable",     0, 1},
 	{TF_With,	"With",         "With",         0, 2},
 	{TF_Except,	"Except",       "Except",       0, 2},
+	{TF_XGenerator,	"XGenerator",   "XGenerator",   0, 1},
 
 	{TF_LIMIT,	"LIMIT",        "LIMIT",        0, 0}
 };

aldor/aldor/src/tform.h

@@ -23,6 +23,7 @@ extern SymeList tfSetSymesFn(TForm, SymeList);
  *
  *****************************************************************************/
 
+// Note that the order is fixed - gen0RtArgHash and fricas need to agree
 enum tformTag {
     TF_START,
     TF_SYM_START = TF_START,
@@ -47,7 +48,6 @@ enum tformTag {
 	TF_Enumerate,
 	TF_Forward,
 	TF_Generator,
-	TF_XGenerator,
 	TF_If,
 	TF_Instance,
 	TF_Join,
@@ -68,6 +68,7 @@ enum tformTag {
 	TF_Variable,
 	TF_With,
         TF_Except,
+	TF_XGenerator,
     TF_NODE_LIMIT,
     TF_LIMIT = TF_NODE_LIMIT
 };