Merge branch 'develop'

6 files changed, 345 insertions, 294 deletions

diff --git a/src/id_table.c b/src/id_table.c
index f0e006a..e113c8f 100644
--- a/src/id_table.c
+++ b/src/id_table.c
@@ -1,7 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include "ast.h"
 #include "id_table.h"
 
 
@@ -19,35 +18,39 @@ void IdTable_init() {
   // START_IS_OF_AGENT .. NUM_AGENTS-1: user defined agents
   // NUM_AGENTS(=ID_NAME) .. : names
 
-  for (i=0; i<IDTABLE_SIZE; i++) {
-    IdTable[i].arity = -1;
+  for (i=0; i<=END_ID_OF_AGENT; i++) {
     IdTable[i].name = NULL;
+    IdTable[i].aux.arity = -1;
+  }
+  for (i=START_ID_OF_GNAME; i<IDTABLE_SIZE; i++) {
+    IdTable[i].name = NULL;
+    IdTable[i].aux.heap = (VALUE)NULL;
   }
 
   // built-in agent
-  IdTable[ID_TUPLE0].arity = 0;
-  IdTable[ID_TUPLE1].arity = 1;
-  IdTable[ID_TUPLE2].arity = 2;
-  IdTable[ID_TUPLE3].arity = 3;
-  IdTable[ID_TUPLE4].arity = 4;
-  IdTable[ID_TUPLE5].arity = 5;
-  IdTable[ID_NIL].arity = 0;
-  IdTable[ID_CONS].arity = 2;
-  IdTable[ID_INTAGENT].arity = 1;
-
-  IdTable[ID_APPEND].arity = 2;
-  IdTable[ID_MERGER].arity = 1;
-  IdTable[ID_MERGER_P].arity = 1;
-  IdTable[ID_ADD].arity = 2;
-  IdTable[ID_ADD2].arity = 2;
-  IdTable[ID_SUB].arity = 2;
-  IdTable[ID_SUB2].arity = 2;
-  IdTable[ID_MUL].arity = 2;
-  IdTable[ID_MUL2].arity = 2;
-  IdTable[ID_DIV].arity = 2;
-  IdTable[ID_DIV2].arity = 2;
-  IdTable[ID_MOD].arity = 2;
-  IdTable[ID_MOD2].arity = 2;
+  IdTable[ID_TUPLE0].aux.arity = 0;
+  IdTable[ID_TUPLE1].aux.arity = 1;
+  IdTable[ID_TUPLE2].aux.arity = 2;
+  IdTable[ID_TUPLE3].aux.arity = 3;
+  IdTable[ID_TUPLE4].aux.arity = 4;
+  IdTable[ID_TUPLE5].aux.arity = 5;
+  IdTable[ID_NIL].aux.arity = 0;
+  IdTable[ID_CONS].aux.arity = 2;
+  IdTable[ID_INTAGENT].aux.arity = 1;
+
+  IdTable[ID_APPEND].aux.arity = 2;
+  IdTable[ID_MERGER].aux.arity = 1;
+  IdTable[ID_MERGER_P].aux.arity = 1;
+  IdTable[ID_ADD].aux.arity = 2;
+  IdTable[ID_ADD2].aux.arity = 2;
+  IdTable[ID_SUB].aux.arity = 2;
+  IdTable[ID_SUB2].aux.arity = 2;
+  IdTable[ID_MUL].aux.arity = 2;
+  IdTable[ID_MUL2].aux.arity = 2;
+  IdTable[ID_DIV].aux.arity = 2;
+  IdTable[ID_DIV2].aux.arity = 2;
+  IdTable[ID_MOD].aux.arity = 2;
+  IdTable[ID_MOD2].aux.arity = 2;
 
   IdTable[ID_INT].name = "int";
   IdTable[ID_TUPLE0].name = "Tuple0";
@@ -162,29 +165,46 @@ void IdTable_set_name(int id, char *symname)
   IdTable[id].name = symname;
 }
 
+char *IdTable_get_name(int id)
+{
+  return IdTable[id].name;
+}
+
 
 void IdTable_set_arity(int id, int arity)
 {
-  if ((IdTable[id].arity == -1) || (IdTable[id].arity == arity)) {
-    IdTable[id].arity = arity;
+  if ((IdTable[id].aux.arity == -1) || (IdTable[id].aux.arity == arity)) {
+    IdTable[id].aux.arity = arity;
   } else {
     printf("Warning: The agent '%s' has been already defined as whose arity is %d, but now used as the arity is %d.\n",  
-	   IdTable[id].name, IdTable[id].arity, arity);
-    IdTable[id].arity = arity;
+	   IdTable[id].name, IdTable[id].aux.arity, arity);
+    IdTable[id].aux.arity = arity;
   } 
 }
 
+int IdTable_get_arity(int id)
+{
+  return IdTable[id].aux.arity;
+}
 
-char *IdTable_get_name(int id)
+
+void IdTable_set_heap(int id, VALUE heap)
 {
-  return IdTable[id].name;
+  if (id > IDTABLE_SIZE) {
+    printf("Error: The given id %d was beyond of the size of IdTable (%d)\n",
+	   id, IDTABLE_SIZE);
+    exit(-1);
+  }
+  IdTable[id].aux.heap = heap;
 }
 
-int IdTable_get_arity(int id)
+VALUE IdTable_get_heap(int id)
 {
-  return IdTable[id].arity;
+  return IdTable[id].aux.heap;
 }
 
+
+
 int IdTable_new_agentid() {
   NextAgentId++;
   if (NextAgentId > ID_NAME) {
diff --git a/src/id_table.h b/src/id_table.h
index ae97c75..02ac9e6 100644
--- a/src/id_table.h
+++ b/src/id_table.h
@@ -1,6 +1,7 @@
 #ifndef _ID_TABLE_
 #define _ID_TABLE_
-
+#include "ast.h"
+#include "mytype.h"
 
 // When NUM_AGENT is 256:
 // 0 .. 255: AGENT
@@ -52,11 +53,11 @@
 #define END_ID_OF_AGENT 255
 #define NUM_AGENTS END_ID_OF_AGENT+1  // 256
 
-#define ID_NAME NUM_AGENTS // 256
+#define ID_NAME NUM_AGENTS // starts from 256 (NUM_AGENTS)
 #define START_ID_OF_GNAME  ID_NAME+1
 
 
-#define NUM_NAMES NUM_AGENTS // 256
+#define NUM_GNAMES NUM_AGENTS // 256: the same as the size of AGENT
 
 
 //#define IS_AGENTID(a) (a < ID_NAME)
@@ -74,16 +75,27 @@
 **************************************/
 typedef struct {
   char *name;
-  int arity;
+  union {
+    int arity;
+    VALUE heap;
+  } aux;
 } IdTableT;
 
-#define IDTABLE_SIZE  (NUM_AGENTS + NUM_NAMES) // AGENT + NAME
+
+#define IDTABLE_SIZE  (NUM_AGENTS + NUM_GNAMES) // AGENT + GNAME
 
 void IdTable_init();
+
 void IdTable_set_name(int id, char *symname);
-void IdTable_set_arity(int id, int arity);
 char *IdTable_get_name(int id);
+
+void IdTable_set_arity(int id, int arity);
 int IdTable_get_arity(int id);
+
+void IdTable_set_heap(int id, VALUE heap);
+VALUE IdTable_get_heap(int id);
+
+
 int IdTable_new_agentid();
 int IdTable_new_gnameid();
 
diff --git a/src/inpla.h b/src/inpla.h
new file mode 100644
index 0000000..2c3f463
--- /dev/null
+++ b/src/inpla.h
@@ -0,0 +1,7 @@
+#ifndef _INPLA_
+#define _INPLA_
+
+void flush_name_port0(VALUE ptr);
+void puts_name_port0(VALUE ptr);
+
+#endif
diff --git a/src/inpla.y b/src/inpla.y
index 398d84e..7bf6404 100644
--- a/src/inpla.y
+++ b/src/inpla.y
@@ -13,7 +13,11 @@
 #include "ast.h"
 #include "id_table.h"
 #include "name_table.h"
+#include "name_table.h"
 #include "mytype.h"
+#include "inpla.h"
+
+
 
 
   
@@ -75,7 +79,7 @@ void freeAgent(VALUE ptr);
 
 void puts_names_ast(Ast *ast);
 void free_names_ast(Ast *ast);
-void puts_name_port0_nat(VALUE ptr);
+void puts_name_port0_nat(char *sym);
 void puts_term(VALUE ptr);
 void puts_aplist(EQList *at);
 
@@ -302,7 +306,7 @@ command:
 
 | PRNAT NAME DELIMITER
 { 
-  puts_name_port0_nat(NameTable_get_heap($2)); 
+  puts_name_port0_nat($2); 
 }
 | INTERFACE DELIMITER
 { 
@@ -1278,7 +1282,13 @@ void puts_names_ast(Ast *ast) {
   
   while (param != NULL) {
     char *sym = param->left->sym;
-    puts_name_port0(NameTable_get_heap(sym));
+    int sym_id = NameTable_get_id(sym);
+    if (IS_GNAMEID(sym_id)) {
+      puts_name_port0(IdTable_get_heap(sym_id));
+    } else {
+      puts_name_port0((VALUE)NULL);
+    }
+      
     param = ast_getTail(param);
     if (param != NULL)
       printf(" ");
@@ -1289,11 +1299,22 @@ void puts_names_ast(Ast *ast) {
   PutIndirection = preserve;  
 }
 
-void puts_name_port0_nat(VALUE a1) {
+//void puts_name_port0_nat(VALUE a1) {
+void puts_name_port0_nat(char *sym) {
   int result=0;
   int idS, idZ;
-  idS = NameTable_get_set_id("S");
-  idZ = NameTable_get_set_id("Z");
+
+  int sym_id = NameTable_get_id(sym);
+  if (!IS_GNAMEID(sym_id)) {
+    printf("<NOT-DEFINED>\n");
+    fflush(stdout);
+    return;
+  }
+
+  VALUE a1 = IdTable_get_heap(sym_id);
+  
+  idS = NameTable_get_set_id_with_IdTable_forAgent("S");
+  idZ = NameTable_get_set_id_with_IdTable_forAgent("Z");
   
   if (a1 == (VALUE)NULL) {
     printf("<NUll>");
@@ -1317,6 +1338,7 @@ void puts_name_port0_nat(VALUE a1) {
 	}
       }
       printf("%d\n", result);
+      fflush(stdout);
     }
   }  
   
@@ -1334,12 +1356,6 @@ void puts_eqlist(EQList *at) {
 }
 
 
-// ----------------------------------------
-// Flush
-
-
-
-
 
 
 /**********************************
@@ -1595,9 +1611,10 @@ void freeName(VALUE ptr) {
   } else {    
     // Global name
 
-    NameTable_erase(IdTable_get_name(BASIC(ptr)->id));
-    //    BASIC(ptr)->id = ID_NAME;
-    SET_LOCAL_NAMEID(BASIC(ptr)->id);
+    NameTable_erase_id(IdTable_get_name(BASIC(ptr)->id));
+    IdTable_set_heap(BASIC(ptr)->id, (VALUE)NULL);
+    
+    SET_LOCAL_NAMEID(BASIC(ptr)->id); //    BASIC(ptr)->id = ID_NAME;
     myfree(ptr);
   }
 
@@ -1706,9 +1723,12 @@ void free_names_ast(Ast *ast) {
   Ast *param = ast;
 
   while (param != NULL) {
-    char *sym = param->left->sym;
-    VALUE heap = NameTable_get_heap(sym);
-    flush_name_port0(heap);
+    int sym_id = NameTable_get_id(param->left->sym);
+    if (IS_GNAMEID(sym_id)) {
+      flush_name_port0(IdTable_get_heap(sym_id));
+    } else {
+      flush_name_port0((VALUE)NULL);
+    }
     param = ast_getTail(param);		     
   }
 }
@@ -1716,15 +1736,6 @@ void free_names_ast(Ast *ast) {
 
 
 
-/**************************************
- NAME TABLE
-**************************************/
-//#include "name_table.h"
-// Just include it, because the object file version causes *inefficiency* !
-#include "name_table.c"  
-
-
-
 
 
 
@@ -2305,21 +2316,33 @@ int CmEnv_check_name_reference_times(void) {
 
 
 void CmEnv_Retrieve_GNAME(void) {
-  int reg_name;
+  int local_var;
 
   for (int i=0; i<IMCode_n; i++) {
     if (IMCode[i].opcode != OP_MKNAME) {
       continue;
     }
 
-    reg_name = IMCode[i].operand1;
+    local_var = IMCode[i].operand1;
 
     for (int j=0; j<CmEnv.bindPtr; j++) {
       if ((CmEnv.bind[j].type == NB_NAME) &&
-	  (CmEnv.bind[j].reg == reg_name) &&
+	  (CmEnv.bind[j].reg == local_var) &&
 	  (CmEnv.bind[j].refnum  == 0)) {
-	    IMCode[i].opcode = OP_MKGNAME;
-	    IMCode[i].operand2 = j;
+
+	// ==> OP_MKGNAME id dest
+	char *sym = CmEnv.bind[j].name;
+	int sym_id = NameTable_get_id(sym);
+	if (!IS_GNAMEID(sym_id)) {
+	  // new occurrence
+	  sym_id = IdTable_new_gnameid();
+	  NameTable_set_id(sym, sym_id);
+	  IdTable_set_name(sym_id, sym);
+	}
+	
+	IMCode[i].opcode = OP_MKGNAME;
+	IMCode[i].operand2 = IMCode[i].operand1;
+	IMCode[i].operand1 = sym_id;
       }
     }
   }      
@@ -2889,19 +2912,18 @@ int CmEnv_generate_VMCode(void **code) {
       break;
     }
     case OP_MKGNAME: {
-      //      printf("OP_MKGNAME var%d sym:%d (as `%s')\n",
+      //      printf("OP_MKGNAME sym:%d var%d (as `%s')\n",
       //	     imcode->operand1, imcode->operand2,
-      //	     CmEnv.bind[imcode->operand2].name);
-      int dest = imcode->operand1;
+      //	     CmEnv.bind[imcode->operand1].name);
+      int dest = imcode->operand2;
 
 #ifdef OPTIMISE_IMCODE
       dest = CmEnv_get_newreg(dest);
 #endif
       
       code[addr++] = CodeAddr[imcode->opcode];
+      code[addr++] = (void *)(unsigned long)imcode->operand1;
       code[addr++] = (void *)(unsigned long)dest;
-      // char*
-      code[addr++] = CmEnv.bind[imcode->operand2].name;
       
       break;
     }
@@ -3781,9 +3803,9 @@ void IMCode_puts(int n) {
       break;
 
     case OP_MKGNAME:
-      printf("%s var%d sym:%d (as \"%s\")\n", string_opcode[imcode->opcode],
+      printf("%s id:%d var%d; \"%s\"\n", string_opcode[imcode->opcode],
 	     imcode->operand1, imcode->operand2,
-	     CmEnv.bind[imcode->operand2].name);
+	     IdTable_get_name(imcode->operand1));
       break;
 
     case OP_MKAGENT0:
@@ -3992,9 +4014,10 @@ void VMCode_puts(void **code, int n) {
       i+=1;
       
     } else if (code[i] == CodeAddr[OP_MKGNAME]) {
-      printf("mkgname reg%lu \"%s\"\n",
+      printf("mkgname id:%lu reg%lu; \"%s\"\n",
 	     (unsigned long)code[i+1],
-	     (char *)code[i+2]);
+	     (unsigned long)code[i+2],
+	     IdTable_get_name((unsigned long)code[i+1]));
       i+=2;
 
     } else if (code[i] == CodeAddr[OP_MKAGENT0]) {
@@ -4800,7 +4823,7 @@ int CompileTermFromAst(Ast *ptr, int target) {
     
     int id = IdTable_getid_builtin_funcAgent(ptr);
     if (id == -1) {
-      id = NameTable_get_set_id((char *)ptr->left->sym);
+      id = NameTable_get_set_id_with_IdTable_forAgent((char *)ptr->left->sym);
     }
 
     arity=0;
@@ -4954,12 +4977,12 @@ int check_invalid_occurrence(Ast *ast) {
   int count;
 
   if (ast->id == AST_NAME) {
-    char *sym = ast->left->sym;
+    int sym_id = NameTable_get_id(ast->left->sym);
 
     
-    VALUE aheap = NameTable_get_heap(sym);
-    if (aheap != (VALUE)NULL) {
+    if (IS_GNAMEID(sym_id)) {
       // already exists as a global
+      VALUE aheap = IdTable_get_heap(sym_id);
 
       /*
       // it is connected with something.
@@ -4974,7 +4997,7 @@ int check_invalid_occurrence(Ast *ast) {
       count = keynode_exists_in_another_term(aheap, NULL);
       if (count == 2) {
 	// already twice
-	printf("ERROR: '%s' occurs twice already. \n", sym);
+	printf("ERROR: '%s' occurs twice already. \n", ast->left->sym);
 	printf("        Use 'ifce' command to see the occurrence.\n");
 	return 1;	    
       }	  
@@ -5582,7 +5605,7 @@ int getRuleAgentID(Ast *ruleAgent) {
 
     id = IdTable_getid_builtin_funcAgent(ruleAgent);
     if (id == -1) {
-      id=NameTable_get_set_id(ruleAgent->left->sym);
+      id=NameTable_get_set_id_with_IdTable_forAgent(ruleAgent->left->sym);
     }
   }
 
@@ -6077,22 +6100,22 @@ void *ExecCode(int mode, VirtualMachine *restrict vm, void *restrict *code) {
   goto *code[pc];
 
  E_MKGNAME:
-  //    puts("mkgname dest sym");
-
-  //a1 = makeGlobalName(vm, (char *)code[pc+1]);
-
-  a1 = NameTable_get_heap((char *)code[pc+2]);
+  //    puts("mkgname id dest");
+  pc++;
+  
+  i = (unsigned long)code[pc++];
+  a1 = IdTable_get_heap(i);
+  //  a1 = NameTable_get_heap((char *)code[pc+2]);
   if (a1 == (VALUE)NULL) {
     a1 = makeName(vm);
 
     // set GID obtained by IdTable_new_gnameid()    
-    i = IdTable_new_gnameid();
-    BASIC(a1)->id = i;  
-    NameTable_set_heap_id((char *)code[pc+2], a1, i);
+    BASIC(a1)->id = i;
+    IdTable_set_heap(i, a1);
+    
   }
 
-  reg[(unsigned long)code[pc+1]] = a1;
-  pc +=3;
+  reg[(unsigned long)code[pc++]] = a1;
   goto *code[pc];
 
   
@@ -6933,80 +6956,6 @@ void *ExecCode(int mode, VirtualMachine *restrict vm, void *restrict *code) {
 ******************************************/
 #ifndef THREAD
 
-/* 30bit目が 1 ならば、Garbage Collection の Mark&Sweep にて、
-   Mark されたことを意味する*/
-#define FLAG_MARKED 0x01 << 30
-#define IS_FLAG_MARKED(a) ((a) & FLAG_MARKED)
-#define SET_FLAG_MARKED(a) ((a) = ((a) | FLAG_MARKED))
-#define TOGGLE_FLAG_MARKED(a) ((a) = ((a) ^ FLAG_MARKED))
-
-
-void markHeapRec(VALUE ptr) {
- loop:  
-  if ((ptr == (VALUE)NULL) || (IS_FIXNUM(ptr))) {
-    return;
-  } else if (IS_NAMEID(BASIC(ptr)->id)) {
-    if (ptr == ShowNameHeap) return;
-
-    SET_FLAG_MARKED(BASIC(ptr)->id);
-    if (NAME(ptr)->port != (VALUE)NULL) {
-      ptr = NAME(ptr)->port;
-      goto loop;
-    }
-  } else {
-    if (BASIC(ptr)->id == ID_CONS) {
-      if (IS_FIXNUM(AGENT(ptr)->port[0])) {
-	SET_FLAG_MARKED(BASIC(ptr)->id);
-	ptr = AGENT(ptr)->port[1];
-	goto loop;
-      }
-    }      
-
-    int arity = IdTable_get_arity(BASIC(ptr)->id);
-    SET_FLAG_MARKED(BASIC(ptr)->id);
-    if (arity == 1) {
-      ptr = AGENT(ptr)->port[0];
-      goto loop;
-    } else { // it also contains the case that arity = 0.
-      int i;
-      for(i=0; i<arity; i++) {
-	markHeapRec(AGENT(ptr)->port[i]);
-      }
-    }
-  }
-}
-
-
-void mark_name_port0(VALUE ptr) {
-  if (ptr != (VALUE)NULL) {
-
-    SET_FLAG_MARKED(BASIC(ptr)->id);
-    if (NAME(ptr)->port != (VALUE)NULL) {
-      ShowNameHeap=ptr;
-      markHeapRec(NAME(ptr)->port);
-      ShowNameHeap=(VALUE)NULL;
-    }      
-  }
-}
-
-
-void mark_allHash(void) {
-  int i;
-  NameList *at;
-
-  for (i=0; i<NAME_HASHSIZE; i++) {
-    at = NameHashTable[i];
-    while (at != NULL) {
-      if (at->heap != (VALUE)NULL) {
-	if (IS_NAMEID(BASIC(at->heap)->id))  {
-	  mark_name_port0(at->heap);
-	}
-      }
-      at = at->next;
-    }
-  }
-}
-
 #ifdef EXPANDABLE_HEAP
 void sweep_AgentHeap(Heap *hp) {
 
@@ -7832,11 +7781,11 @@ loop_a2IsAgent:
 
 
 void select_kind_of_push(Ast *ast, int p1, int p2) {  
-  char *sym = ast->left->sym;
-  VALUE aheap = NameTable_get_heap(sym);
+  int sym_id = NameTable_get_id(ast->left->sym);
   
-  if (aheap != (VALUE)NULL) {
+  if (IS_GNAMEID(sym_id)) {
     // aheap already exists as a global
+    VALUE aheap = IdTable_get_heap(sym_id);
     
     // aheap is connected with something such as aheap->t
     // ==> p2 should be conncected with t, so OP_CNCTGN(p1,p2)
@@ -7992,11 +7941,11 @@ int exec(Ast *at) {
     return 0;
   }
 
-  
+
   CmEnv_Retrieve_GNAME();
   CmEnv_generate_VMCode(code);
 
-
+  
   /*
   // for debug
   CmEnv_Retrieve_GNAME();
@@ -8006,7 +7955,6 @@ int exec(Ast *at) {
   VMCode_puts(code, codenum-2); //exit(1);
   // end for debug
   */
-
   
   
 #ifdef COUNT_MKAGENT
diff --git a/src/name_table.c b/src/name_table.c
index b6ed9a1..06ff955 100644
--- a/src/name_table.c
+++ b/src/name_table.c
@@ -51,73 +51,9 @@ int getHash(char *key)
 
 
 
-void NameTable_set_heap_id(char *key, VALUE heap, IDTYPE id) {
-  // Set (id, heap) for the key in the name table.
-  
-  int hash;
-  NameList *add;
-  hash = getHash(key);
-    
-  if (NameHashTable[hash] == NULL) {  
-    // When the linear list of the hash table is EMPTY
-
-    // Make a new linear list
-    add = NameList_new(); 
-
-    // Set (id, heap) for the key
-    add->name = key;
-    add->id = id;
-    IdTable_set_name(id, key);
-    add->heap = heap;
-    add->next = NULL;
-
-    // Store the liner list to the hash table
-    NameHashTable[hash] = add;
-    return;
-  }
 
 
-  // linear search for the key
-  NameList *at = NameHashTable[hash];
-
-  while (at != NULL) {
-    
-    if (strcmp(at->name, key) == 0) {
-      // already exists
-
-      // set (id, heap) for the key
-      at->id = id;
-      IdTable_set_name(at->id, key);
-      at->heap = heap;
-      return;
-
-    }
-    at = at->next;
-  }
-
-
-  // The case of no entries
-
-  // Make a new linear list
-  add = NameList_new();
-
-  // Set (id, heap) for the key
-  add->name = key;  
-  add->id = id;
-  IdTable_set_name(add->id, key);
-  add->heap = heap;
-
-  // Change the first element of the hash table into me.
-  add->next = NameHashTable[hash];
-  NameHashTable[hash] = add;
-  
-  return;
-}
-
-
-
-
-void NameTable_erase(char *key) {
+void NameTable_erase_id(char *key) {
   // Delete the entry for the key
   
   int hash;
@@ -140,17 +76,7 @@ void NameTable_erase(char *key) {
     if (strcmp(at->name, key) == 0) {
       // already exists
 
-      // No need to be freed
-      // because it stores just a pointer to the heap,
-      // and this function is expected to remove only the information.
-      at->heap = (VALUE)NULL;
-      //at->id = -1;                  // id stores -1 for the deleted condition.
-                                    // It is not mandatory,
-                                    // but 10% less performance causes
-                                    // if we omit this. WHY?
-                                    // 2021-10-06: it was not caused,
-                                    // so it was commented out.
-
+      at->id = -1;
       return;
       
     }
@@ -162,32 +88,32 @@ void NameTable_erase(char *key) {
 
 
 
-VALUE NameTable_get_heap(char *key) {
+int NameTable_get_id(char *key) {
   int hash;
   
   hash = getHash(key);
   
   if (NameHashTable[hash] == NULL) {
-    return (VALUE)NULL;
+    return -1;
   }
 
   NameList *at = NameHashTable[hash];
   while (at != NULL) {
     if (strcmp(at->name, key) == 0) {
       // already exists
-      return at->heap;
+      return at->id;
     }
     
     at = at->next;
   }
   
   // There is no entry for the key
-  return (VALUE)NULL;
+  return -1;
   
 }
 
 
-IDTYPE NameTable_get_set_id(char *key) {
+IDTYPE NameTable_get_set_id_with_IdTable_forAgent(char *key) {
   int hash;
   NameList *add;
 
@@ -200,7 +126,6 @@ IDTYPE NameTable_get_set_id(char *key) {
     add->name = key;
     add->id = IdTable_new_agentid();
     IdTable_set_name(add->id, add->name);
-    add->heap = (VALUE)NULL;
     add->next = NULL;
     NameHashTable[hash] = add;
     return (add->id);
@@ -221,7 +146,6 @@ IDTYPE NameTable_get_set_id(char *key) {
   add->name = key;  
   add->id = IdTable_new_agentid();
   IdTable_set_name(add->id, add->name);
-  add->heap = (VALUE)NULL;
   
   add->next = NameHashTable[hash];
   NameHashTable[hash] = add;
@@ -231,6 +155,47 @@ IDTYPE NameTable_get_set_id(char *key) {
 
 
 
+void NameTable_set_id(char *key, IDTYPE id) {
+  int hash;
+  NameList *add;
+
+
+  hash = getHash(key);
+  
+  if (NameHashTable[hash] == NULL) {
+
+    add = NameList_new();
+    add->name = key;
+    add->id = id;
+    add->next = NULL;
+    NameHashTable[hash] = add;
+    return;
+
+  }
+  
+  NameList *at = NameHashTable[hash];
+  while (at != NULL) {
+    if (strcmp(at->name, key) == 0) {
+      at->id = id;
+      return;
+      
+    }
+    at = at->next;
+  }
+  
+
+  add = NameList_new();
+  add->name = key;  
+  add->id = id;
+  
+  add->next = NameHashTable[hash];
+  NameHashTable[hash] = add;
+
+  return;
+}
+
+
+
 
 
 
@@ -282,12 +247,13 @@ int keynode_exists_in_another_term(VALUE keynode, VALUE *connected_from) {
   for (i=0; i<NAME_HASHSIZE; i++) {
     at = NameHashTable[i];
     while (at != NULL) {
-      if (at->heap != (VALUE)NULL) {
-	if (at->heap != keynode)  {
-	  if (term_has_keynode(keynode, at->heap)) {
+      if (IS_GNAMEID(at->id)) {
+	VALUE heap = IdTable_get_heap(at->id);
+	if (heap != keynode)  {
+	  if (term_has_keynode(keynode, heap)) {
 	    result++;
 	    if (connected_from != NULL) {
-	      *connected_from = at->heap;
+	      *connected_from = heap;
 	    }
 	    /*
 	    PutIndirection=1;
@@ -348,14 +314,19 @@ void global_replace_keynode_in_another_term(VALUE keynode, VALUE term) {
   for (i=0; i<NAME_HASHSIZE; i++) {
     at = NameHashTable[i];
     while (at != NULL) {
-      if (at->heap != (VALUE)NULL) {
-	if (at->heap != keynode)  {
+      if (IS_GNAMEID(at->id)) {
+	VALUE heap = IdTable_get_heap(at->id);
+
+	if (heap != keynode)  {
 	  
-	  if (term_has_keynode(keynode, at->heap)) {
+	  if (term_has_keynode(keynode, heap)) {
+
+	    // replaced <- heap[term/keynode]
+	    VALUE replaced = replace_keynode(keynode, term, heap);
+	    IdTable_set_heap(at->id, replaced);
+
+	    //freeName(keynode); <-- this is called at the calling function.
 
-	    VALUE replaced = replace_keynode(keynode, term, at->heap);
-	    at->heap = replaced;
-	    
 	    return;
 	  }
 	}
@@ -376,9 +347,10 @@ void NameTable_puts_all() {
   for (i=0; i<NAME_HASHSIZE; i++) {
     at = NameHashTable[i];
     while (at != NULL) {
-      if (at->heap != (VALUE)NULL) {
-	if (IS_NAMEID(BASIC(at->heap)->id))  {
-	  printf("%s ", IdTable_get_name(BASIC(at->heap)->id));
+      if (IS_GNAMEID(at->id)) {
+	VALUE heap = IdTable_get_heap(at->id);
+	if (IS_NAMEID(BASIC(heap)->id))  {
+	  printf("%s ", IdTable_get_name(BASIC(heap)->id));
 	  count++;
 	}
       }
@@ -395,10 +367,11 @@ void NameTable_puts_all() {
   for (i=0; i<NAME_HASHSIZE; i++) {
     at = NameHashTable[i];
     while (at != NULL) {
-      if (at->heap != (VALUE)NULL) {
-	if (IS_NAMEID(BASIC(at->heap)->id))  {
-	  printf("%s ->", IdTable_get_name(BASIC(at->heap)->id));
-	  puts_name_port0(at->heap);
+      if (IS_GNAMEID(at->id)) {
+	VALUE heap = IdTable_get_heap(at->id);	
+	if (IS_NAMEID(BASIC(heap)->id))  {
+	  printf("%s ->", IdTable_get_name(BASIC(heap)->id));
+	  puts_name_port0(heap);
 	  printf("\n");
 	}
       }
@@ -416,9 +389,10 @@ void NameTable_free_all() {
   for (i=0; i<NAME_HASHSIZE; i++) {
     at = NameHashTable[i];
     while (at != NULL) {
-      if (at->heap != (VALUE)NULL) {
-	if (IS_NAMEID(BASIC(at->heap)->id))  {
-	  flush_name_port0(at->heap);
+      if (IS_GNAMEID(at->id)) {
+	VALUE heap = IdTable_get_heap(at->id);	
+	if (IS_NAMEID(BASIC(heap)->id))  {
+	  flush_name_port0(heap);
 	}
       }
       at = at->next;
@@ -430,13 +404,13 @@ void NameTable_free_all() {
 int NameTable_check_if_term_has_gname(VALUE term) {
   int i;
   NameList *at;
-  VALUE ptr;
   
   for (i=0; i<NAME_HASHSIZE; i++) {
     at = NameHashTable[i];
     while (at != NULL) {
-      if (at->heap != (VALUE)NULL) {
-	ptr = at->heap;
+      if (IS_GNAMEID(at->id)) {
+	VALUE ptr = IdTable_get_heap(at->id);	
+	
 	while ((ptr != (VALUE)NULL) &&
 	       (! IS_FIXNUM(ptr)) &&
 	       (IS_NAMEID(BASIC(ptr)->id))) {
@@ -458,3 +432,79 @@ int NameTable_check_if_term_has_gname(VALUE term) {
   return 0;
 }
 
+
+
+/******************************************
+ Mark and Sweep for error recovery
+******************************************/
+#ifndef THREAD
+static VALUE CyclicNameHeap=(VALUE)NULL;
+
+void markHeapRec(VALUE ptr) {
+ loop:  
+  if ((ptr == (VALUE)NULL) || (IS_FIXNUM(ptr))) {
+    return;
+  } else if (IS_NAMEID(BASIC(ptr)->id)) {
+    if (ptr == CyclicNameHeap) return;
+
+    SET_FLAG_MARKED(BASIC(ptr)->id);
+    if (NAME(ptr)->port != (VALUE)NULL) {
+      ptr = NAME(ptr)->port;
+      goto loop;
+    }
+  } else {
+    if (BASIC(ptr)->id == ID_CONS) {
+      if (IS_FIXNUM(AGENT(ptr)->port[0])) {
+	SET_FLAG_MARKED(BASIC(ptr)->id);
+	ptr = AGENT(ptr)->port[1];
+	goto loop;
+      }
+    }      
+
+    int arity = IdTable_get_arity(BASIC(ptr)->id);
+    SET_FLAG_MARKED(BASIC(ptr)->id);
+    if (arity == 1) {
+      ptr = AGENT(ptr)->port[0];
+      goto loop;
+    } else { // it also contains the case that arity = 0.
+      int i;
+      for(i=0; i<arity; i++) {
+	markHeapRec(AGENT(ptr)->port[i]);
+      }
+    }
+  }
+}
+
+
+void mark_name_port0(VALUE ptr) {
+  if (ptr != (VALUE)NULL) {
+
+    SET_FLAG_MARKED(BASIC(ptr)->id);
+    if (NAME(ptr)->port != (VALUE)NULL) {
+      CyclicNameHeap=ptr;
+      markHeapRec(NAME(ptr)->port);
+      CyclicNameHeap=(VALUE)NULL;
+    }      
+  }
+}
+
+
+void mark_allHash(void) {
+  int i;
+  NameList *at;
+
+  for (i=0; i<NAME_HASHSIZE; i++) {
+    at = NameHashTable[i];
+    while (at != NULL) {
+      if (IS_GNAMEID(at->id)) {
+	VALUE heap = IdTable_get_heap(at->id);	
+
+	if (IS_NAMEID(BASIC(heap)->id))  {
+	  mark_name_port0(heap);
+	}
+      }
+      at = at->next;
+    }
+  }
+}
+#endif
diff --git a/src/name_table.h b/src/name_table.h
index 4bc1361..70d71cc 100644
--- a/src/name_table.h
+++ b/src/name_table.h
@@ -3,7 +3,7 @@
 
 #include "mytype.h"
 #include "id_table.h"
-
+#include "inpla.h"
 
 /**************************************
  NAME TABLE
@@ -15,13 +15,9 @@
 
 
 typedef struct NameList {
-  char *name;             // KEY
-  IDTYPE id;
+  char *name;          // KEY
+  int id;              // -1: no entry
 
-  // `heap' stores a heap only of a global name,
-  // that is, is kept having NULL for other nodes, such as agents.
-  VALUE heap;
-  
   struct NameList *next;
 } NameList;
 
@@ -35,12 +31,16 @@ void NameTable_init();
 void NameTable_set_heap_id(char *key, VALUE heap, IDTYPE id);
 
 
-// Erace key entry from NameHashTable
-void NameTable_erase(char *key);
+// Set id at key entry to -1
+void NameTable_erase_id(char *key);
+
+
+int NameTable_get_id(char *key);
+void NameTable_set_id(char *key, IDTYPE id);
 
 
-VALUE NameTable_get_heap(char *key);
-IDTYPE NameTable_get_set_id(char *key);
+IDTYPE NameTable_get_set_id_with_IdTable_forAgent(char *key);
+
 
 void NameTable_puts_all();
 void NameTable_free_all();
@@ -52,4 +52,18 @@ int keynode_exists_in_another_term(VALUE keynode, VALUE *connected_from);
 void global_replace_keynode_in_another_term(VALUE keynode, VALUE term);
 
 
+#ifndef THREAD
+//  Mark and Sweep for error recovery
+
+/* 30bit目が 1 ならば、Garbage Collection の Mark&Sweep にて、
+   Mark されたことを意味する*/
+#define FLAG_MARKED 0x01 << 30
+#define IS_FLAG_MARKED(a) ((a) & FLAG_MARKED)
+#define SET_FLAG_MARKED(a) ((a) = ((a) | FLAG_MARKED))
+#define TOGGLE_FLAG_MARKED(a) ((a) = ((a) ^ FLAG_MARKED))
+
+void mark_allHash(void);
+#endif
+
+
 #endif