Merge pull request #169 from mitchblank/cplusplus

Part 1 of C++ compilability

16 files changed, 258 insertions, 241 deletions

diff --git a/include/mruby.h b/include/mruby.h
index 9e7d20351..ed5fe79d2 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -81,7 +81,7 @@ typedef struct mrb_value {
 #define mrb_fixnum(o) (o).value.i
 #define mrb_float(o)  (o).value.f
 #define mrb_symbol(o) (o).value.sym
-#define mrb_object(o) (o).value.p
+#define mrb_object(o) ((struct RObject *) (o).value.p)
 #define FIXNUM_P(o)   ((o).tt == MRB_TT_FIXNUM)
 #define UNDEF_P(o)    ((o).tt == MRB_TT_UNDEF)
 
@@ -368,11 +368,11 @@ int mrb_gc_arena_save(mrb_state*);
 void mrb_gc_arena_restore(mrb_state*,int);
 void mrb_gc_mark(mrb_state*,struct RBasic*);
 #define mrb_gc_mark_value(mrb,val) do {\
-  if ((val).tt >= MRB_TT_OBJECT) mrb_gc_mark((mrb), mrb_object(val));\
+  if ((val).tt >= MRB_TT_OBJECT) mrb_gc_mark((mrb), (struct RBasic *) mrb_object(val));\
 } while (0);
 void mrb_field_write_barrier(mrb_state *, struct RBasic*, struct RBasic*);
 #define mrb_field_write_barrier_value(mrb, obj, val) do{\
-  if ((val.tt >= MRB_TT_OBJECT)) mrb_field_write_barrier((mrb), (obj), mrb_object(val));\
+  if ((val.tt >= MRB_TT_OBJECT)) mrb_field_write_barrier((mrb), (obj), (struct RBasic *) mrb_object(val));\
 } while (0);
 void mrb_write_barrier(mrb_state *, struct RBasic*);
 
diff --git a/include/mruby/range.h b/include/mruby/range.h
index b95838375..036cdd574 100644
--- a/include/mruby/range.h
+++ b/include/mruby/range.h
@@ -11,12 +11,14 @@
 extern "C" {
 #endif
 
+struct mrb_range_edges {
+  mrb_value beg;
+  mrb_value end;
+};
+
 struct RRange {
   MRUBY_OBJECT_HEADER;
-  struct mrb_range_edges {
-    mrb_value beg;
-    mrb_value end;
-  } *edges;
+  struct mrb_range_edges *edges;
   int excl;
 };
 
diff --git a/src/class.c b/src/class.c
index ee8cb8f48..eda3f87a0 100644
--- a/src/class.c
+++ b/src/class.c
@@ -1003,10 +1003,10 @@ mrb_value
 mrb_mod_alias(mrb_state *mrb, mrb_value mod)
 {
   struct RClass *c = mrb_class_ptr(mod);
-  mrb_value new, old;
+  mrb_value new_value, old_value;
 
-  mrb_get_args(mrb, "oo", &new, &old);
-  mrb_alias_method(mrb, c, mrb_symbol(new), mrb_symbol(old));
+  mrb_get_args(mrb, "oo", &new_value, &old_value);
+  mrb_alias_method(mrb, c, mrb_symbol(new_value), mrb_symbol(old_value));
   return mrb_nil_value();
 }
 
diff --git a/src/codegen.c b/src/codegen.c
index 769f9e538..263490f27 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -20,14 +20,16 @@
 typedef mrb_ast_node node;
 typedef struct mrb_parser_state parser_state;
 
+enum looptype {
+  LOOP_NORMAL,
+  LOOP_BLOCK,
+  LOOP_FOR,
+  LOOP_BEGIN,
+  LOOP_RESCUE,
+} type;
+
 struct loopinfo {
-  enum looptype {
-    LOOP_NORMAL,
-    LOOP_BLOCK,
-    LOOP_FOR,
-    LOOP_BEGIN,
-    LOOP_RESCUE,
-  } type;
+  enum looptype type;
   int pc1, pc2, pc3, acc;
   int ensure_level;
   struct loopinfo *prev;
diff --git a/src/encoding.c b/src/encoding.c
index 8a3bd8ef2..cfe21b581 100644
--- a/src/encoding.c
+++ b/src/encoding.c
@@ -913,11 +913,11 @@ enc_name(mrb_state *mrb, mrb_value self)
 
 struct fn_arg {
   mrb_state *mrb;
-  int (*func)(ANYARGS);
+  enum st_retval (*func)(ANYARGS);
   void *a;
 };
 
-static int
+static enum st_retval
 fn_i(st_data_t key, st_data_t val, st_data_t arg) {
   struct fn_arg *a = (struct fn_arg*)arg;
 
@@ -925,7 +925,7 @@ fn_i(st_data_t key, st_data_t val, st_data_t arg) {
 }
 
 static int
-st_foreachNew(mrb_state *mrb, st_table *tbl, int (*func)(ANYARGS), void *a)
+st_foreachNew(mrb_state *mrb, st_table *tbl, enum st_retval (*func)(ANYARGS), void *a)
 {
   struct fn_arg arg = {
     mrb,
@@ -936,7 +936,7 @@ st_foreachNew(mrb_state *mrb, st_table *tbl, int (*func)(ANYARGS), void *a)
   return st_foreach(tbl, fn_i, (st_data_t)&arg);
 }
 
-static int
+static enum st_retval
 enc_names_i(mrb_state *mrb, st_data_t name, st_data_t idx, st_data_t args)
 {
   mrb_value *arg = (mrb_value *)args;
@@ -1521,7 +1521,7 @@ set_encoding_const(mrb_state *mrb, const char *name, mrb_encoding *enc)
     }
   }
 }
-static int
+static enum st_retval
 mrb_enc_name_list_i(mrb_state *mrb, st_data_t name, st_data_t idx, mrb_value *arg)
 {
     mrb_value ary = *arg;
@@ -1554,7 +1554,7 @@ mrb_enc_name_list(mrb_state *mrb, mrb_value klass)
     return ary;
 }
 
-static int
+static enum st_retval
 mrb_enc_aliases_enc_i(mrb_state *mrb, st_data_t name, st_data_t orig, st_data_t arg)
 {
     mrb_value *p = (mrb_value *)arg;
diff --git a/src/gc.h b/src/gc.h
index 0a4bc1c51..fea761d1b 100644
--- a/src/gc.h
+++ b/src/gc.h
@@ -11,12 +11,14 @@
 extern "C" {
 #endif
 
+struct free_obj {
+  MRUBY_OBJECT_HEADER;
+  struct RBasic *next;
+};
+
 typedef struct {
   union {
-    struct free_obj {
-      MRUBY_OBJECT_HEADER;
-      struct RBasic *next;
-    } free;
+    struct free_obj free;
     struct RBasic basic;
     struct RObject object;
     struct RClass klass;
diff --git a/src/hash.c b/src/hash.c
index a435b4afd..45219cb40 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -75,10 +75,10 @@ mrb_gc_mark_ht(mrb_state *mrb, struct RHash *c)
 }
 
 size_t
-mrb_gc_mark_ht_size(mrb_state *mrb, struct RClass *c)
+mrb_gc_mark_ht_size(mrb_state *mrb, struct RHash *c)
 {
   size_t ht_size = 0;
-  khash_t(ht) *h = ((struct RHash*)c)->ht;
+  khash_t(ht) *h = c->ht;
 
   /* ((struct RHash*)c)->ht */
   if (h) ht_size += kh_size(h)*2;
@@ -87,9 +87,9 @@ mrb_gc_mark_ht_size(mrb_state *mrb, struct RClass *c)
 }
 
 void
-mrb_gc_free_ht(mrb_state *mrb, struct RClass *c)
+mrb_gc_free_ht(mrb_state *mrb, struct RHash *c)
 {
-  khash_t(ht) *h = ((struct RHash*)c)->ht;
+  khash_t(ht) *h = c->ht;
 
   kh_destroy(ht, h);
 }
diff --git a/src/parse.y b/src/parse.y
index 63c15e056..96f399fb0 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -813,7 +813,7 @@ var_reference(parser_state *p, node *lhs)
 %lex-param {parser_state *p}
 
 %union {
-    node *node;
+    node *nd;
     mrb_sym id;
     int num;
     unsigned int stack;
@@ -871,28 +871,28 @@ var_reference(parser_state *p, node *lhs)
 	keyword__ENCODING__
 
 %token <id>   tIDENTIFIER tFID tGVAR tIVAR tCONSTANT tCVAR tLABEL
-%token <node> tINTEGER tFLOAT tCHAR tREGEXP
-%token <node> tSTRING tSTRING_PART
-%token <node> tNTH_REF tBACK_REF
+%token <nd> tINTEGER tFLOAT tCHAR tREGEXP
+%token <nd> tSTRING tSTRING_PART
+%token <nd> tNTH_REF tBACK_REF
 %token <num>  tREGEXP_END
 
-%type <node> singleton string string_interp regexp
-%type <node> literal numeric cpath
-%type <node> top_compstmt top_stmts top_stmt
-%type <node> bodystmt compstmt stmts stmt expr arg primary command command_call method_call
-%type <node> expr_value arg_value primary_value
-%type <node> if_tail opt_else case_body cases opt_rescue exc_list exc_var opt_ensure
-%type <node> args call_args opt_call_args
-%type <node> paren_args opt_paren_args variable
-%type <node> command_args aref_args opt_block_arg block_arg var_ref var_lhs
-%type <node> command_asgn mrhs superclass block_call block_command
-%type <node> f_block_optarg f_block_opt
-%type <node> f_arglist f_args f_arg f_arg_item f_optarg f_marg f_marg_list f_margs
-%type <node> assoc_list assocs assoc undef_list backref for_var
-%type <node> block_param opt_block_param block_param_def f_opt
-%type <node> bv_decls opt_bv_decl bvar f_larglist lambda_body
-%type <node> brace_block cmd_brace_block do_block lhs none fitem f_bad_arg
-%type <node> mlhs mlhs_list mlhs_post mlhs_basic mlhs_item mlhs_node mlhs_inner
+%type <nd> singleton string string_interp regexp
+%type <nd> literal numeric cpath
+%type <nd> top_compstmt top_stmts top_stmt
+%type <nd> bodystmt compstmt stmts stmt expr arg primary command command_call method_call
+%type <nd> expr_value arg_value primary_value
+%type <nd> if_tail opt_else case_body cases opt_rescue exc_list exc_var opt_ensure
+%type <nd> args call_args opt_call_args
+%type <nd> paren_args opt_paren_args variable
+%type <nd> command_args aref_args opt_block_arg block_arg var_ref var_lhs
+%type <nd> command_asgn mrhs superclass block_call block_command
+%type <nd> f_block_optarg f_block_opt
+%type <nd> f_arglist f_args f_arg f_arg_item f_optarg f_marg f_marg_list f_margs
+%type <nd> assoc_list assocs assoc undef_list backref for_var
+%type <nd> block_param opt_block_param block_param_def f_opt
+%type <nd> bv_decls opt_bv_decl bvar f_larglist lambda_body
+%type <nd> brace_block cmd_brace_block do_block lhs none fitem f_bad_arg
+%type <nd> mlhs mlhs_list mlhs_post mlhs_basic mlhs_item mlhs_node mlhs_inner
 %type <id>   fsym sym symbol operation operation2 operation3
 %type <id>   cname fname op f_rest_arg f_block_arg opt_f_block_arg f_norm_arg
 
@@ -1007,12 +1007,12 @@ top_stmt	: stmt
 		      if (p->in_def || p->in_single) {
 			yyerror(p, "BEGIN in method");
 		      }
-		      $<node>$ = local_switch(p);
+		      $<nd>$ = local_switch(p);
 		    }
 		  '{' top_compstmt '}'
 		    {
 		      p->begin_tree = push(p->begin_tree, $4);
-		      local_resume(p, $<node>2);
+		      local_resume(p, $<nd>2);
 		      $$ = 0;
 		    }
 		;
@@ -1980,13 +1980,13 @@ primary		: literal
 		    {
 		      if (p->in_def || p->in_single)
 			yyerror(p, "class definition in method body");
-		      $<node>$ = local_switch(p);
+		      $<nd>$ = local_switch(p);
 		    }
 		  bodystmt
 		  keyword_end
 		    {
 		      $$ = new_class(p, $2, $3, $5);
-		      local_resume(p, $<node>4);
+		      local_resume(p, $<nd>4);
 		    }
 		| keyword_class tLSHFT expr
 		    {
@@ -1995,54 +1995,54 @@ primary		: literal
 		    }
 		  term
 		    {
-		      $<node>$ = cons(local_switch(p), (node*)(intptr_t)p->in_single);
+		      $<nd>$ = cons(local_switch(p), (node*)(intptr_t)p->in_single);
 		      p->in_single = 0;
 		    }
 		  bodystmt
 		  keyword_end
 		    {
 		      $$ = new_sclass(p, $3, $7);
-		      local_resume(p, $<node>6->car);
+		      local_resume(p, $<nd>6->car);
 		      p->in_def = $<num>4;
-		      p->in_single = (int)(intptr_t)$<node>6->cdr;
+		      p->in_single = (int)(intptr_t)$<nd>6->cdr;
 		    }
 		| keyword_module cpath
 		    {
 		      if (p->in_def || p->in_single)
 			yyerror(p, "module definition in method body");
-		      $<node>$ = local_switch(p);
+		      $<nd>$ = local_switch(p);
 		    }
 		  bodystmt
 		  keyword_end
 		    {
 		      $$ = new_module(p, $2, $4);
-		      local_resume(p, $<node>3);
+		      local_resume(p, $<nd>3);
 		    }
 		| keyword_def fname
 		    {
 		      p->in_def++;
-		      $<node>$ = local_switch(p);
+		      $<nd>$ = local_switch(p);
 		    }
 		  f_arglist
 		  bodystmt
 		  keyword_end
 		    {
 		      $$ = new_def(p, $2, $4, $5);
-		      local_resume(p, $<node>3);
+		      local_resume(p, $<nd>3);
 		      p->in_def--;
 		    }
 		| keyword_def singleton dot_or_colon {p->lstate = EXPR_FNAME;} fname
 		    {
 		      p->in_single++;
 		      p->lstate = EXPR_ENDFN; /* force for args */
-		      $<node>$ = local_switch(p);
+		      $<nd>$ = local_switch(p);
 		    }
 		  f_arglist
 		  bodystmt
 		  keyword_end
 		    {
 		      $$ = new_sdef(p, $2, $5, $7, $8);
-		      local_resume(p, $<node>6);
+		      local_resume(p, $<nd>6);
 		      p->in_single--;
 		    }
 		| keyword_break
@@ -3355,7 +3355,7 @@ parse_string(parser_state *p, int term)
 	p->lstate = EXPR_BEG;
 	p->sterm = term;
 	p->cmd_start = TRUE;
-	yylval.node = new_str(p, tok(p), toklen(p));
+	yylval.nd = new_str(p, tok(p), toklen(p));
 	return tSTRING_PART;
       }
       tokadd(p, '#');
@@ -3368,7 +3368,7 @@ parse_string(parser_state *p, int term)
   tokfix(p);
   p->lstate = EXPR_END;
   p->sterm = 0;
-  yylval.node = new_str(p, tok(p), toklen(p));
+  yylval.nd = new_str(p, tok(p), toklen(p));
   return tSTRING;
 }
 
@@ -3409,7 +3409,7 @@ parse_qstring(parser_state *p, int term)
   }
 
   tokfix(p);
-  yylval.node = new_str(p, tok(p), toklen(p));
+  yylval.nd = new_str(p, tok(p), toklen(p));
   p->lstate = EXPR_END;
   return tSTRING;
 }
@@ -3717,7 +3717,7 @@ parser_yylex(parser_state *p)
       tokadd(p, c);
     }
     tokfix(p);
-    yylval.node = new_str(p, tok(p), toklen(p));
+    yylval.nd = new_str(p, tok(p), toklen(p));
     p->lstate = EXPR_END;
     return tCHAR;
 
@@ -3894,7 +3894,7 @@ parser_yylex(parser_state *p)
 	    no_digits();
 	  }
 	  else if (nondigit) goto trailing_uc;
-	  yylval.node = new_int(p, tok(p), 16);
+	  yylval.nd = new_int(p, tok(p), 16);
 	  return tINTEGER;
 	}
 	if (c == 'b' || c == 'B') {
@@ -3918,7 +3918,7 @@ parser_yylex(parser_state *p)
 	    no_digits();
 	  }
 	  else if (nondigit) goto trailing_uc;
-	  yylval.node = new_int(p, tok(p), 2);
+	  yylval.nd = new_int(p, tok(p), 2);
 	  return tINTEGER;
 	}
 	if (c == 'd' || c == 'D') {
@@ -3942,7 +3942,7 @@ parser_yylex(parser_state *p)
 	    no_digits();
 	  }
 	  else if (nondigit) goto trailing_uc;
-	  yylval.node = new_int(p, tok(p), 10);
+	  yylval.nd = new_int(p, tok(p), 10);
 	  return tINTEGER;
 	}
 	if (c == '_') {
@@ -3975,7 +3975,7 @@ parser_yylex(parser_state *p)
 	    pushback(p, c);
 	    tokfix(p);
 	    if (nondigit) goto trailing_uc;
-	    yylval.node = new_int(p, tok(p), 8);
+	    yylval.nd = new_int(p, tok(p), 8);
 	    return tINTEGER;
 	  }
 	  if (nondigit) {
@@ -3992,7 +3992,7 @@ parser_yylex(parser_state *p)
 	}
 	else {
 	  pushback(p, c);
-	  yylval.node = new_int(p, "0", 10);
+	  yylval.nd = new_int(p, "0", 10);
 	  return tINTEGER;
 	}
       }
@@ -4069,10 +4069,10 @@ parser_yylex(parser_state *p)
 	  yywarning_s(p, "float %s out of range", tok(p));
 	  errno = 0;
 	}
-	yylval.node = new_float(p, tok(p));
+	yylval.nd = new_float(p, tok(p));
 	return tFLOAT;
       }
-      yylval.node = new_int(p, tok(p), 10);
+      yylval.nd = new_int(p, tok(p), 10);
       return tINTEGER;
     }
 
@@ -4404,7 +4404,7 @@ parser_yylex(parser_state *p)
 	tokadd(p, c);
 	goto gvar;
       }
-      yylval.node = new_back_ref(p, c);
+      yylval.nd = new_back_ref(p, c);
       return tBACK_REF;
 
     case '1': case '2': case '3':
@@ -4417,7 +4417,7 @@ parser_yylex(parser_state *p)
       pushback(p, c);
       if (last_state == EXPR_FNAME) goto gvar;
       tokfix(p);
-      yylval.node = new_nth_ref(p, atoi(tok(p))); 
+      yylval.nd = new_nth_ref(p, atoi(tok(p))); 
       return tNTH_REF;
 
     default:
diff --git a/src/pool.c b/src/pool.c
index a367a30a5..3cbb2b163 100644
--- a/src/pool.c
+++ b/src/pool.c
@@ -8,15 +8,17 @@
 #include <stddef.h>
 #include <string.h>
 
+struct mrb_pool_page {
+  struct mrb_pool_page *next;
+  size_t offset;
+  size_t len;
+  void *last;
+  char page[1];
+};
+
 struct mrb_pool {
   mrb_state *mrb;
-  struct mrb_pool_page {
-    struct mrb_pool_page *next;
-    size_t offset;
-    size_t len;
-    void *last;
-    char page[1];
-  } *pages;
+  struct mrb_pool_page *pages;
 };
 
 #undef TEST_POOL
diff --git a/src/regcomp.c b/src/regcomp.c
index 816e219c7..523124b26 100644
--- a/src/regcomp.c
+++ b/src/regcomp.c
@@ -1640,8 +1640,8 @@ compile_tree(Node* node, regex_t* reg)
 
       switch (NCTYPE(node)->ctype) {
       case ONIGENC_CTYPE_WORD:
-        if (NCTYPE(node)->not != 0)  op = OP_NOT_WORD;
-        else                         op = OP_WORD;
+        if (NCTYPE(node)->is_not != 0)  op = OP_NOT_WORD;
+        else                            op = OP_WORD;
         break;
       default:
         return ONIGERR_TYPE_BUG;
@@ -2440,8 +2440,8 @@ is_not_included(Node* x, Node* y, regex_t* reg)
     {
       switch (ytype) {
       case NT_CTYPE:
-        if (NCTYPE(y)->ctype == NCTYPE(x)->ctype &&
-            NCTYPE(y)->not   != NCTYPE(x)->not)
+        if (NCTYPE(y)->ctype  == NCTYPE(x)->ctype &&
+            NCTYPE(y)->is_not != NCTYPE(x)->is_not)
           return 1;
         else
           return 0;
@@ -2473,7 +2473,7 @@ is_not_included(Node* x, Node* y, regex_t* reg)
       case NT_CTYPE:
         switch (NCTYPE(y)->ctype) {
         case ONIGENC_CTYPE_WORD:
-          if (NCTYPE(y)->not == 0) {
+          if (NCTYPE(y)->is_not == 0) {
             if (IS_NULL(xc->mbuf) && !IS_NCCLASS_NOT(xc)) {
               for (i = 0; i < SINGLE_BYTE_SIZE; i++) {
                 if (BITSET_AT(xc->bs, i)) {
@@ -2550,9 +2550,9 @@ is_not_included(Node* x, Node* y, regex_t* reg)
         switch (NCTYPE(y)->ctype) {
         case ONIGENC_CTYPE_WORD:
           if (ONIGENC_IS_MBC_WORD(reg->enc, xs->s, xs->end))
-            return NCTYPE(y)->not;
+            return NCTYPE(y)->is_not;
           else
-            return !(NCTYPE(y)->not);
+            return !(NCTYPE(y)->is_not);
           break;
         default:
           break;
@@ -3038,19 +3038,21 @@ setup_subexp_call(Node* node, ScanEnv* env)
       Node** nodes = SCANENV_MEM_NODES(env);
 
       if (cn->group_num != 0) {
-        int gnum = cn->group_num;
+        {
+          int gnum = cn->group_num;
 
 #ifdef USE_NAMED_GROUP
-        if (env->num_named > 0 &&
-            IS_SYNTAX_BV(env->syntax, ONIG_SYN_CAPTURE_ONLY_NAMED_GROUP) &&
-            !ONIG_IS_OPTION_ON(env->option, ONIG_OPTION_CAPTURE_GROUP)) {
-          return ONIGERR_NUMBERED_BACKREF_OR_CALL_NOT_ALLOWED;
-        }
+          if (env->num_named > 0 &&
+              IS_SYNTAX_BV(env->syntax, ONIG_SYN_CAPTURE_ONLY_NAMED_GROUP) &&
+              !ONIG_IS_OPTION_ON(env->option, ONIG_OPTION_CAPTURE_GROUP)) {
+            return ONIGERR_NUMBERED_BACKREF_OR_CALL_NOT_ALLOWED;
+          }
 #endif
-        if (gnum > env->num_mem) {
-          onig_scan_env_set_error_string(env,
-                 ONIGERR_UNDEFINED_GROUP_REFERENCE, cn->name, cn->name_end);
-          return ONIGERR_UNDEFINED_GROUP_REFERENCE;
+          if (gnum > env->num_mem) {
+            onig_scan_env_set_error_string(env,
+                   ONIGERR_UNDEFINED_GROUP_REFERENCE, cn->name, cn->name_end);
+            return ONIGERR_UNDEFINED_GROUP_REFERENCE;
+          }
         }
 
 #ifdef USE_NAMED_GROUP
@@ -4668,7 +4670,7 @@ optimize_node_left(Node* node, NodeOptInfo* opt, OptEnv* env)
 
         switch (NCTYPE(node)->ctype) {
         case ONIGENC_CTYPE_WORD:
-          if (NCTYPE(node)->not != 0) {
+          if (NCTYPE(node)->is_not != 0) {
             for (i = 0; i < SINGLE_BYTE_SIZE; i++) {
               if (! ONIGENC_IS_CODE_WORD(env->enc, i)) {
                 add_char_opt_map_info(&opt->map, (UChar )i, env->enc);
@@ -6170,7 +6172,7 @@ print_indent_tree(FILE* f, Node* node, int indent)
     fprintf(f, "<ctype:%x> ", (int )node);
     switch (NCTYPE(node)->ctype) {
     case ONIGENC_CTYPE_WORD:
-      if (NCTYPE(node)->not != 0)
+      if (NCTYPE(node)->is_not != 0)
         fputs("not word",       f);
       else
         fputs("word",           f);
diff --git a/src/regparse.c b/src/regparse.c
index ee933662c..f98e82ff2 100644
--- a/src/regparse.c
+++ b/src/regparse.c
@@ -416,7 +416,7 @@ typedef st_data_t HashDataType;   /* 1.6 st.h doesn't define st_data_t type */
 #define NAMEBUF_SIZE_1  25
 
 #ifdef ONIG_DEBUG
-static int
+static enum st_retval
 i_print_name_entry(UChar* key, NameEntry* e, void* arg)
 {
   int i;
@@ -451,7 +451,7 @@ onig_print_names(FILE* fp, regex_t* reg)
 }
 #endif /* ONIG_DEBUG */
 
-static int
+static enum st_retval
 i_free_name_entry(UChar* key, NameEntry* e, void* arg ARG_UNUSED)
 {
   xfree(e->name);
@@ -508,7 +508,7 @@ typedef struct {
   OnigEncoding enc;
 } INamesArg;
 
-static int
+static enum st_retval
 i_names(UChar* key ARG_UNUSED, NameEntry* e, INamesArg* arg)
 {
   int r = (*(arg->func))(e->name,
@@ -541,7 +541,7 @@ onig_foreach_name(regex_t* reg,
   return narg.ret;
 }
 
-static int
+static enum st_retval
 i_renumber_name(UChar* key ARG_UNUSED, NameEntry* e, GroupNumRemap* map)
 {
   int i;
@@ -1151,7 +1151,7 @@ node_new_cclass(void)
 }
 
 static Node*
-node_new_cclass_by_codepoint_range(int not, OnigCodePoint sb_out,
+node_new_cclass_by_codepoint_range(int is_not, OnigCodePoint sb_out,
                                    const OnigCodePoint ranges[])
 {
   int n, i;
@@ -1162,7 +1162,7 @@ node_new_cclass_by_codepoint_range(int not, OnigCodePoint sb_out,
   CHECK_NULL_RETURN(node);
 
   cc = NCCLASS(node);
-  if (not != 0) NCCLASS_SET_NOT(cc);
+  if (is_not != 0) NCCLASS_SET_NOT(cc);
 
   BITSET_CLEAR(cc->bs);
   if (sb_out > 0 && IS_NOT_NULL(ranges)) {
@@ -1201,14 +1201,14 @@ node_new_cclass_by_codepoint_range(int not, OnigCodePoint sb_out,
 }
 
 static Node*
-node_new_ctype(int type, int not)
+node_new_ctype(int type, int is_not)
 {
   Node* node = node_new();
   CHECK_NULL_RETURN(node);
 
   SET_NTYPE(node, NT_CTYPE);
-  NCTYPE(node)->ctype = type;
-  NCTYPE(node)->not   = not;
+  NCTYPE(node)->ctype  = type;
+  NCTYPE(node)->is_not = is_not;
   return node;
 }
 
@@ -2285,7 +2285,7 @@ typedef struct {
     } call;
     struct {
       int ctype;
-      int not;
+      int is_not;
     } prop;
   } u;
 } OnigToken;
@@ -2954,45 +2954,45 @@ fetch_token_in_cc(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
     switch (c) {
     case 'w':
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_W;
-      tok->u.prop.not   = 0;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_W;
+      tok->u.prop.is_not = 0;
       break;
     case 'W':
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_W;
-      tok->u.prop.not   = 1;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_W;
+      tok->u.prop.is_not = 1;
       break;
     case 'd':
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_D;
-      tok->u.prop.not   = 0;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_D;
+      tok->u.prop.is_not = 0;
       break;
     case 'D':
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_D;
-      tok->u.prop.not   = 1;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_D;
+      tok->u.prop.is_not = 1;
       break;
     case 's':
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_S;
-      tok->u.prop.not   = 0;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_S;
+      tok->u.prop.is_not = 0;
       break;
     case 'S':
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_S;
-      tok->u.prop.not   = 1;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_S;
+      tok->u.prop.is_not = 1;
       break;
     case 'h':
       if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_H_XDIGIT)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_XDIGIT;
-      tok->u.prop.not   = 0;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_XDIGIT;
+      tok->u.prop.is_not = 0;
       break;
     case 'H':
       if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_H_XDIGIT)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_XDIGIT;
-      tok->u.prop.not   = 1;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_XDIGIT;
+      tok->u.prop.is_not = 1;
       break;
 
     case 'p':
@@ -3002,12 +3002,12 @@ fetch_token_in_cc(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
           IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_P_BRACE_CHAR_PROPERTY)) {
         PINC;
         tok->type = TK_CHAR_PROPERTY;
-        tok->u.prop.not = (c == 'P' ? 1 : 0);
+        tok->u.prop.is_not = (c == 'P' ? 1 : 0);
 
         if (IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT)) {
           PFETCH(c2);
           if (c2 == '^') {
-            tok->u.prop.not = (tok->u.prop.not == 0 ? 1 : 0);
+            tok->u.prop.is_not = (tok->u.prop.is_not == 0 ? 1 : 0);
           }
           else
             PUNFETCH;
@@ -3244,15 +3244,15 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
     case 'w':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_W_WORD)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_W;
-      tok->u.prop.not   = 0;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_W;
+      tok->u.prop.is_not = 0;
       break;
 
     case 'W':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_W_WORD)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_W;
-      tok->u.prop.not   = 1;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_W;
+      tok->u.prop.is_not = 1;
       break;
 
     case 'b':
@@ -3284,43 +3284,43 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
     case 's':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_S_WHITE_SPACE)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_S;
-      tok->u.prop.not   = 0;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_S;
+      tok->u.prop.is_not = 0;
       break;
 
     case 'S':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_S_WHITE_SPACE)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_S;
-      tok->u.prop.not   = 1;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_S;
+      tok->u.prop.is_not = 1;
       break;
 
     case 'd':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_D_DIGIT)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_D;
-      tok->u.prop.not   = 0;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_D;
+      tok->u.prop.is_not = 0;
       break;
 
     case 'D':
       if (! IS_SYNTAX_OP(syn, ONIG_SYN_OP_ESC_D_DIGIT)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_D;
-      tok->u.prop.not   = 1;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_D;
+      tok->u.prop.is_not = 1;
       break;
 
     case 'h':
       if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_H_XDIGIT)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_XDIGIT;
-      tok->u.prop.not   = 0;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_XDIGIT;
+      tok->u.prop.is_not = 0;
       break;
 
     case 'H':
       if (! IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_H_XDIGIT)) break;
       tok->type = TK_CHAR_TYPE;
-      tok->u.prop.ctype = ONIGENC_CTYPE_XDIGIT;
-      tok->u.prop.not   = 1;
+      tok->u.prop.ctype  = ONIGENC_CTYPE_XDIGIT;
+      tok->u.prop.is_not = 1;
       break;
 
     case 'A':
@@ -3574,12 +3574,12 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
           IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_P_BRACE_CHAR_PROPERTY)) {
         PINC;
         tok->type = TK_CHAR_PROPERTY;
-        tok->u.prop.not = (c == 'P' ? 1 : 0);
+        tok->u.prop.is_not = (c == 'P' ? 1 : 0);
 
         if (IS_SYNTAX_OP2(syn, ONIG_SYN_OP2_ESC_P_BRACE_CIRCUMFLEX_NOT)) {
           PFETCH(c);
           if (c == '^') {
-            tok->u.prop.not = (tok->u.prop.not == 0 ? 1 : 0);
+            tok->u.prop.is_not = (tok->u.prop.is_not == 0 ? 1 : 0);
           }
           else
             PUNFETCH;
@@ -3773,7 +3773,7 @@ fetch_token(OnigToken* tok, UChar** src, UChar* end, ScanEnv* env)
 }
 
 static int
-add_ctype_to_cc_by_range(CClassNode* cc, int ctype ARG_UNUSED, int not,
+add_ctype_to_cc_by_range(CClassNode* cc, int ctype ARG_UNUSED, int is_not,
                          ScanEnv* env,
                          OnigCodePoint sb_out, const OnigCodePoint mbr[])
 {
@@ -3782,7 +3782,7 @@ add_ctype_to_cc_by_range(CClassNode* cc, int ctype ARG_UNUSED, int not,
 
   int n = ONIGENC_CODE_RANGE_NUM(mbr);
 
-  if (not == 0) {
+  if (is_not == 0) {
     for (i = 0; i < n; i++) {
       for (j  = ONIGENC_CODE_RANGE_FROM(mbr, i);
            j <= ONIGENC_CODE_RANGE_TO(mbr, i); j++) {
@@ -3846,7 +3846,7 @@ add_ctype_to_cc_by_range(CClassNode* cc, int ctype ARG_UNUSED, int not,
 }
 
 static int
-add_ctype_to_cc(CClassNode* cc, int ctype, int not, ScanEnv* env)
+add_ctype_to_cc(CClassNode* cc, int ctype, int is_not, ScanEnv* env)
 {
   int c, r;
   const OnigCodePoint *ranges;
@@ -3858,7 +3858,7 @@ add_ctype_to_cc(CClassNode* cc, int ctype, int not, ScanEnv* env)
   case ONIGENC_CTYPE_S:
   case ONIGENC_CTYPE_W:
     ctype ^= ONIGENC_CTYPE_SPECIAL_MASK;
-    if (not != 0) {
+    if (is_not != 0) {
       for (c = 0; c < SINGLE_BYTE_SIZE; c++) {
         if (! ONIGENC_IS_ASCII_CODE_CTYPE((OnigCodePoint )c, ctype))
           BITSET_SET_BIT_CHKDUP(cc->bs, c);
@@ -3877,7 +3877,7 @@ add_ctype_to_cc(CClassNode* cc, int ctype, int not, ScanEnv* env)
 
   r = ONIGENC_GET_CTYPE_CODE_RANGE(enc, ctype, &sb_out, &ranges);
   if (r == 0) {
-    return add_ctype_to_cc_by_range(cc, ctype, not, env, sb_out, ranges);
+    return add_ctype_to_cc_by_range(cc, ctype, is_not, env, sb_out, ranges);
   }
   else if (r != ONIG_NO_SUPPORT_CONFIG) {
     return r;
@@ -3896,7 +3896,7 @@ add_ctype_to_cc(CClassNode* cc, int ctype, int not, ScanEnv* env)
   case ONIGENC_CTYPE_XDIGIT:
   case ONIGENC_CTYPE_ASCII:
   case ONIGENC_CTYPE_ALNUM:
-    if (not != 0) {
+    if (is_not != 0) {
       for (c = 0; c < SINGLE_BYTE_SIZE; c++) {
         if (! ONIGENC_IS_CODE_CTYPE(enc, (OnigCodePoint )c, ctype))
           BITSET_SET_BIT_CHKDUP(cc->bs, c);
@@ -3913,7 +3913,7 @@ add_ctype_to_cc(CClassNode* cc, int ctype, int not, ScanEnv* env)
 
   case ONIGENC_CTYPE_GRAPH:
   case ONIGENC_CTYPE_PRINT:
-    if (not != 0) {
+    if (is_not != 0) {
       for (c = 0; c < SINGLE_BYTE_SIZE; c++) {
         if (! ONIGENC_IS_CODE_CTYPE(enc, (OnigCodePoint )c, ctype))
           BITSET_SET_BIT_CHKDUP(cc->bs, c);
@@ -3929,7 +3929,7 @@ add_ctype_to_cc(CClassNode* cc, int ctype, int not, ScanEnv* env)
     break;
 
   case ONIGENC_CTYPE_WORD:
-    if (not == 0) {
+    if (is_not == 0) {
       for (c = 0; c < SINGLE_BYTE_SIZE; c++) {
         if (IS_CODE_SB_WORD(enc, c)) BITSET_SET_BIT_CHKDUP(cc->bs, c);
       }
@@ -3977,7 +3977,7 @@ parse_posix_bracket(CClassNode* cc, UChar** src, UChar* end, ScanEnv* env)
   };
 
   const PosixBracketEntryType *pb;
-  int not, i, r;
+  int is_not, i, r;
   OnigCodePoint c;
   OnigEncoding enc = env->enc;
   UChar *p = *src;
@@ -3985,10 +3985,10 @@ parse_posix_bracket(CClassNode* cc, UChar** src, UChar* end, ScanEnv* env)
 
   if (PPEEK_IS('^')) {
     PINC;
-    not = 1;
+    is_not = 1;
   }
   else
-    not = 0;
+    is_not = 0;
 
   if (onigenc_strlen(enc, p, end) < POSIX_BRACKET_NAME_MIN_LEN + 3)
     goto not_posix_bracket;
@@ -3999,7 +3999,7 @@ parse_posix_bracket(CClassNode* cc, UChar** src, UChar* end, ScanEnv* env)
       if (onigenc_with_ascii_strncmp(enc, p, end, (UChar* )":]", 2) != 0)
         return ONIGERR_INVALID_POSIX_BRACKET_TYPE;
 
-      r = add_ctype_to_cc(cc, pb->ctype, not, env);
+      r = add_ctype_to_cc(cc, pb->ctype, is_not, env);
       if (r != 0) return r;
 
       PINC; PINC;
@@ -4074,7 +4074,7 @@ parse_char_property(Node** np, OnigToken* tok, UChar** src, UChar* end,
   cc = NCCLASS(*np);
   r = add_ctype_to_cc(cc, ctype, 0, env);
   if (r != 0) return r;
-  if (tok->u.prop.not != 0) NCCLASS_SET_NOT(cc);
+  if (tok->u.prop.is_not != 0) NCCLASS_SET_NOT(cc);
 
   return 0;
 }
@@ -4356,7 +4356,7 @@ parse_char_class(Node** np, OnigToken* tok, UChar** src, UChar* end,
       break;
 
     case TK_CHAR_TYPE:
-      r = add_ctype_to_cc(cc, tok->u.prop.ctype, tok->u.prop.not, env);
+      r = add_ctype_to_cc(cc, tok->u.prop.ctype, tok->u.prop.is_not, env);
       if (r != 0) return r;
 
     next_class:
@@ -4370,7 +4370,7 @@ parse_char_class(Node** np, OnigToken* tok, UChar** src, UChar* end,
 
         ctype = fetch_char_property_to_ctype(&p, end, env);
         if (ctype < 0) return ctype;
-        r = add_ctype_to_cc(cc, ctype, tok->u.prop.not, env);
+        r = add_ctype_to_cc(cc, ctype, tok->u.prop.is_not, env);
         if (r != 0) return r;
         goto next_class;
       }
@@ -4881,15 +4881,15 @@ set_quantifier(Node* qnode, Node* target, int group, ScanEnv* env)
 
 typedef struct {
   OnigEncoding enc;
-  int not;
+  int is_not;
   int type;
 } type_cclass_key;
 
 static int type_cclass_cmp(type_cclass_key* x, type_cclass_key* y)
 {
-  if (x->type != y->type) return 1;
-  if (x->enc  != y->enc)  return 1;
-  if (x->not  != y->not)  return 1;
+  if (x->type   != y->type) return 1;
+  if (x->enc    != y->enc)  return 1;
+  if (x->is_not != y->is_not)  return 1;
   return 0;
 }
 
@@ -4910,7 +4910,7 @@ static st_index_t type_cclass_hash(type_cclass_key* key)
     val = val * 997 + (int )*p++;
   }
 
-  val += key->not;
+  val += key->is_not;
   return val + (val >> 5);
 }
 
@@ -4922,7 +4922,7 @@ static const struct st_hash_type type_type_cclass_hash = {
 static st_table* OnigTypeCClassTable;
 
 
-static int
+static enum st_retval
 i_free_shared_class(type_cclass_key* key, Node* node, void* arg ARG_UNUSED)
 {
   if (IS_NOT_NULL(node)) {
@@ -5208,12 +5208,12 @@ parse_exp(Node** np, OnigToken* tok, int term,
             CHECK_NULL_RETURN_MEMERR(*np);
             cc = NCCLASS(*np);
             add_ctype_to_cc(cc, tok->u.prop.ctype, 0, env);
-            if (tok->u.prop.not != 0) NCCLASS_SET_NOT(cc);
+            if (tok->u.prop.is_not != 0) NCCLASS_SET_NOT(cc);
         }
         break;
 
       case ONIGENC_CTYPE_WORD:
-        *np = node_new_ctype(tok->u.prop.ctype, tok->u.prop.not);
+        *np = node_new_ctype(tok->u.prop.ctype, tok->u.prop.is_not);
         CHECK_NULL_RETURN_MEMERR(*np);
         break;
 
@@ -5235,9 +5235,9 @@ parse_exp(Node** np, OnigToken* tok, int term,
             type_cclass_key  key;
             type_cclass_key* new_key;
 
-            key.enc  = env->enc;
-            key.not  = tok->u.prop.not;
-            key.type = tok->u.prop.ctype;
+            key.enc    = env->enc;
+            key.is_not = tok->u.prop.is_not;
+            key.type   = tok->u.prop.ctype;
 
             THREAD_ATOMIC_START;
 
@@ -5257,7 +5257,7 @@ parse_exp(Node** np, OnigToken* tok, int term,
               }
             }
 
-            *np = node_new_cclass_by_codepoint_range(tok->u.prop.not,
+            *np = node_new_cclass_by_codepoint_range(tok->u.prop.is_not,
                                                      sb_out, mbr);
             if (IS_NULL(*np)) {
               THREAD_ATOMIC_END;
@@ -5279,7 +5279,7 @@ parse_exp(Node** np, OnigToken* tok, int term,
             CHECK_NULL_RETURN_MEMERR(*np);
             cc = NCCLASS(*np);
             add_ctype_to_cc(cc, tok->u.prop.ctype, 0, env);
-            if (tok->u.prop.not != 0) NCCLASS_SET_NOT(cc);
+            if (tok->u.prop.is_not != 0) NCCLASS_SET_NOT(cc);
 #ifdef USE_SHARED_CCLASS_TABLE
           }
 #endif
diff --git a/src/regparse.h b/src/regparse.h
index ac8758bd1..1f7855df8 100644
--- a/src/regparse.h
+++ b/src/regparse.h
@@ -247,7 +247,7 @@ typedef struct {
 typedef struct {
   NodeBase base;
   int ctype;
-  int not;
+  int is_not;
 } CtypeNode;
 
 typedef struct _Node {
diff --git a/src/sprintf.c b/src/sprintf.c
index 12d96c92d..6a86a0d04 100644
--- a/src/sprintf.c
+++ b/src/sprintf.c
@@ -191,7 +191,7 @@ mrb_fix2binstr(mrb_state *mrb, mrb_value x, int base)
 } while (0)
 
 static mrb_value
-get_hash(mrb_state *mrb, volatile mrb_value *hash, int argc, const mrb_value *argv)
+get_hash(mrb_state *mrb, mrb_value *hash, int argc, const mrb_value *argv)
 {
   mrb_value tmp;
 
@@ -497,7 +497,7 @@ mrb_str_format(mrb_state *mrb, int argc, const mrb_value *argv, mrb_value fmt)
   mrb_value nextvalue;
   mrb_value tmp;
   mrb_value str;
-  volatile mrb_value hash = mrb_undef_value();
+  mrb_value hash = mrb_undef_value();
 
 #define CHECK_FOR_WIDTH(f)                                                  \
   if ((f) & FWIDTH) {                                                       \
@@ -772,7 +772,7 @@ format_s:
     case 'B':
     case 'u':
       {
-        volatile mrb_value val = GETARG();
+        mrb_value val = GETARG();
         char fbuf[32], nbuf[64], *s;
         const char *prefix = 0;
         int sign = 0, dots = 0;
diff --git a/src/st.c b/src/st.c
index 777a03bd2..c0597395d 100644
--- a/src/st.c
+++ b/src/st.c
@@ -404,7 +404,7 @@ st_delete(register st_table *table, register st_data_t *key, st_data_t *value)
 }
 
 int
-st_foreach(st_table *table, int (*func)(ANYARGS), st_data_t arg)
+st_foreach(st_table *table, enum st_retval (*func)(ANYARGS), st_data_t arg)
 {
     st_table_entry *ptr, **last, *tmp;
     enum st_retval retval;
@@ -572,7 +572,7 @@ numhash(long n)
 }
 
 #if 0
-static int
+static enum st_retval
 f(st_data_t key, st_data_t val, st_data_t a)
 {
   printf("tbl=%p key=%s val=%s\n", (st_table*)a, (char*)key, (char*)val);
diff --git a/src/st.h b/src/st.h
index 24db1fd23..2be618041 100644
--- a/src/st.h
+++ b/src/st.h
@@ -74,7 +74,7 @@ int st_delete(st_table *, st_data_t *, st_data_t *);
 int st_delete_safe(st_table *, st_data_t *, st_data_t *, st_data_t);
 int st_insert(st_table *, st_data_t, st_data_t);
 int st_lookup(st_table *, st_data_t, st_data_t *);
-int st_foreach(st_table *, int (*)(ANYARGS), st_data_t);
+int st_foreach(st_table *, enum st_retval (*)(ANYARGS), st_data_t);
 void st_add_direct(st_table *, st_data_t, st_data_t);
 void st_free_table(st_table *);
 void st_cleanup_safe(st_table *, st_data_t);
diff --git a/src/transcode.c b/src/transcode.c
index 42c86d167..e9d9b01ef 100644
--- a/src/transcode.c
+++ b/src/transcode.c
@@ -65,6 +65,12 @@ allocate_converted_string(mrb_state *mrb,
         unsigned char *caller_dst_buf, size_t caller_dst_bufsize,
         size_t *dst_len_ptr);
 
+union mrb_transcoding_state_t { /* opaque data for stateful encoding */
+    void *ptr;
+    char ary[sizeof(double) > sizeof(void*) ? sizeof(double) : sizeof(void*)];
+    double dummy_for_alignment;
+};
+
 /* dynamic structure, one per conversion (similar to iconv_t) */
 /* may carry conversion state (e.g. for iso-2022-jp) */
 typedef struct mrb_transcoding {
@@ -92,11 +98,7 @@ typedef struct mrb_transcoding {
         unsigned char *ptr; /* length: max_output */
     } writebuf;
 
-    union mrb_transcoding_state_t { /* opaque data for stateful encoding */
-        void *ptr;
-        char ary[sizeof(double) > sizeof(void*) ? sizeof(double) : sizeof(void*)];
-        double dummy_for_alignment;
-    } state;
+    union mrb_transcoding_state_t state;
 } mrb_transcoding;
 #define TRANSCODING_READBUF(tc) \
     ((tc)->transcoder->max_input <= (int)sizeof((tc)->readbuf.ary) ? \
@@ -271,7 +273,7 @@ typedef struct {
     const char *base_enc;
 } search_path_bfs_t;
 
-static int
+static enum st_retval
 transcode_search_path_i(st_data_t key, st_data_t val, st_data_t arg)
 {
     const char *dname = (const char *)key;
@@ -577,10 +579,12 @@ transcode_restartable0(mrb_state *mrb,
       switch (mrb_fixnum(next_info) & 0x1F) {
         case NOMAP:
             {
-                const unsigned char *p = inchar_start;
-                writebuf_off = 0;
-                while (p < in_p) {
-                    TRANSCODING_WRITEBUF(tc)[writebuf_off++] = (unsigned char)*p++;
+                {
+                    const unsigned char *p = inchar_start;
+                    writebuf_off = 0;
+                    while (p < in_p) {
+                        TRANSCODING_WRITEBUF(tc)[writebuf_off++] = (unsigned char)*p++;
+                    }
                 }
                 writebuf_len = writebuf_off;
                 writebuf_off = 0;
@@ -1125,16 +1129,16 @@ trans_sweep(mrb_state *mrb, mrb_econv_t *ec,
     int flags,
     int start)
 {
-    int try;
+    int should_try;
     int i, f;
 
     const unsigned char **ipp, *is, *iold;
     unsigned char **opp, *os, *oold;
     mrb_econv_result_t res;
 
-    try = 1;
-    while (try) {
-        try = 0;
+    should_try = 1;
+    while (should_try) {
+        should_try = 0;
         for (i = start; i < ec->num_trans; i++) {
             mrb_econv_elem_t *te = &ec->elems[i];
 
@@ -1177,7 +1181,7 @@ trans_sweep(mrb_state *mrb, mrb_econv_t *ec,
             oold = *opp;
             te->last_result = res = mrb_transcoding_convert(mrb, te->tc, ipp, is, opp, os, f);
             if (iold != *ipp || oold != *opp)
-                try = 1;
+                should_try = 1;
 
             switch (res) {
               case econv_invalid_byte_sequence:
@@ -1795,7 +1799,7 @@ struct asciicompat_encoding_t {
     const char *ascii_incompat_name;
 };
 
-static int
+static enum st_retval
 asciicompat_encoding_i(mrb_state *mrb, st_data_t key, st_data_t val, st_data_t arg)
 {
     struct asciicompat_encoding_t *data = (struct asciicompat_encoding_t *)arg;
@@ -2083,51 +2087,54 @@ make_econv_exception(mrb_state *mrb, mrb_econv_t *ec)
     mrb_value mesg, exc;
     if (ec->last_error.result == econv_invalid_byte_sequence ||
         ec->last_error.result == econv_incomplete_input) {
-        const char *err = (const char *)ec->last_error.error_bytes_start;
-        size_t error_len = ec->last_error.error_bytes_len;
-        mrb_value bytes = mrb_str_new(mrb, err, error_len);
-        mrb_value dumped = mrb_str_dump(mrb, bytes);
-        size_t readagain_len = ec->last_error.readagain_len;
-        mrb_value bytes2 = mrb_nil_value();
-        mrb_value dumped2;
-        int idx;
-        if (ec->last_error.result == econv_incomplete_input) {
-            mesg = mrb_sprintf(mrb, "incomplete %s on %s",
-                    //StringValueCStr(dumped),
-                    mrb_string_value_cstr(mrb, &dumped),
-                    ec->last_error.source_encoding);
-        }
-        else if (readagain_len) {
-            bytes2 = mrb_str_new(mrb, err+error_len, readagain_len);
-            dumped2 = mrb_str_dump(mrb, bytes2);
-            mesg = mrb_sprintf(mrb, "%s followed by %s on %s",
-                    //StringValueCStr(dumped),
-                    mrb_string_value_cstr(mrb, &dumped),
-                    //StringValueCStr(dumped2),
-                    mrb_string_value_cstr(mrb, &dumped2),
-                    ec->last_error.source_encoding);
-        }
-        else {
-            mesg = mrb_sprintf(mrb, "%s on %s",
-                    //StringValueCStr(dumped),
-                    mrb_string_value_cstr(mrb, &dumped),
-                    ec->last_error.source_encoding);
+        {
+            const char *err = (const char *)ec->last_error.error_bytes_start;
+            size_t error_len = ec->last_error.error_bytes_len;
+            mrb_value bytes = mrb_str_new(mrb, err, error_len);
+            mrb_value dumped = mrb_str_dump(mrb, bytes);
+            size_t readagain_len = ec->last_error.readagain_len;
+            mrb_value bytes2 = mrb_nil_value();
+            mrb_value dumped2;
+            if (ec->last_error.result == econv_incomplete_input) {
+                mesg = mrb_sprintf(mrb, "incomplete %s on %s",
+                        //StringValueCStr(dumped),
+                        mrb_string_value_cstr(mrb, &dumped),
+                        ec->last_error.source_encoding);
+            }
+            else if (readagain_len) {
+                bytes2 = mrb_str_new(mrb, err+error_len, readagain_len);
+                dumped2 = mrb_str_dump(mrb, bytes2);
+                mesg = mrb_sprintf(mrb, "%s followed by %s on %s",
+                        //StringValueCStr(dumped),
+                        mrb_string_value_cstr(mrb, &dumped),
+                        //StringValueCStr(dumped2),
+                        mrb_string_value_cstr(mrb, &dumped2),
+                        ec->last_error.source_encoding);
+            }
+            else {
+                mesg = mrb_sprintf(mrb, "%s on %s",
+                        //StringValueCStr(dumped),
+                        mrb_string_value_cstr(mrb, &dumped),
+                        ec->last_error.source_encoding);
+            }
+    
+            exc = mrb_exc_new3(mrb, E_INVALIDBYTESEQUENCE_ERROR, mesg);
+            mrb_iv_set(mrb, exc, mrb_intern(mrb, "error_bytes"), bytes);
+            mrb_iv_set(mrb, exc, mrb_intern(mrb, "readagain_bytes"), bytes2);
+            mrb_iv_set(mrb, exc, mrb_intern(mrb, "incomplete_input"), ec->last_error.result == econv_incomplete_input ? mrb_true_value() : mrb_false_value());
         }
 
-        exc = mrb_exc_new3(mrb, E_INVALIDBYTESEQUENCE_ERROR, mesg);
-        mrb_iv_set(mrb, exc, mrb_intern(mrb, "error_bytes"), bytes);
-        mrb_iv_set(mrb, exc, mrb_intern(mrb, "readagain_bytes"), bytes2);
-        mrb_iv_set(mrb, exc, mrb_intern(mrb, "incomplete_input"), ec->last_error.result == econv_incomplete_input ? mrb_true_value() : mrb_false_value());
-
 set_encs:
         mrb_iv_set(mrb, exc, mrb_intern(mrb, "source_encoding_name"), mrb_str_new2(mrb, ec->last_error.source_encoding));
         mrb_iv_set(mrb, exc, mrb_intern(mrb, "destination_encoding_name"), mrb_str_new2(mrb, ec->last_error.destination_encoding));
-        idx = mrb_enc_find_index(mrb, ec->last_error.source_encoding);
-        if (0 <= idx)
-            mrb_iv_set(mrb, exc, mrb_intern(mrb, "source_encoding"), mrb_enc_from_encoding(mrb, mrb_enc_from_index(mrb, idx)));
-        idx = mrb_enc_find_index(mrb, ec->last_error.destination_encoding);
-        if (0 <= idx)
-            mrb_iv_set(mrb, exc, mrb_intern(mrb, "destination_encoding"), mrb_enc_from_encoding(mrb, mrb_enc_from_index(mrb, idx)));
+        {
+            int idx = mrb_enc_find_index(mrb, ec->last_error.source_encoding);
+            if (0 <= idx)
+                mrb_iv_set(mrb, exc, mrb_intern(mrb, "source_encoding"), mrb_enc_from_encoding(mrb, mrb_enc_from_index(mrb, idx)));
+            idx = mrb_enc_find_index(mrb, ec->last_error.destination_encoding);
+            if (0 <= idx)
+                mrb_iv_set(mrb, exc, mrb_intern(mrb, "destination_encoding"), mrb_enc_from_encoding(mrb, mrb_enc_from_index(mrb, idx)));
+        }
         return exc;
     }
     if (ec->last_error.result == econv_undefined_conversion) {