diff --git a/bin/main.c b/bin/main.c
index a27976c..fce8a19 100644
--- a/bin/main.c
+++ b/bin/main.c
@@ -435,75 +435,6 @@ static hcl_oop_t execute_in_batch_mode (hcl_t* hcl, int verbose)
 	return retv;
 }
 
-static int main_loop (hcl_t* hcl, xtn_t* xtn, int cflags, int verbose)
-{
-	while (1)
-	{
-		hcl_cnode_t* obj;
-		int n;
-
-/*
-static int count = 0;
-if (count %5 == 0) hcl_reset (hcl);
-count++;
-*/
-		obj = hcl_read(hcl);
-		if (!obj)
-		{
-			if (hcl->errnum == HCL_EFINIS)
-			{
-				/* end of input */
-				break;
-			}
-			else if (hcl->errnum == HCL_ESYNERR)
-			{
-				print_synerr (hcl);
-				if (hcl_isstdreadertty(hcl) && hcl_getsynerrnum(hcl) != HCL_SYNERR_EOF)
-				{
-					/* TODO: drain remaining data in the reader including the actual input stream and buffered data in hcl */
-					continue;
-				}
-			}
-			else
-			{
-				hcl_logbfmt (hcl, HCL_LOG_STDERR, "ERROR: cannot read object - [%d] %js\n", hcl_geterrnum(hcl), hcl_geterrmsg(hcl));
-			}
-			goto oops;
-		}
-
-		if (verbose) hcl_prbfmt (hcl, "\n"); /* flush the output buffer by hcl_print above */
-		n = hcl_compile(hcl, obj, cflags);
-		hcl_freecnode (hcl, obj); /* not needed any more */
-
-		if (n <= -1)
-		{
-			if (hcl->errnum == HCL_ESYNERR)
-			{
-				print_synerr (hcl);
-			}
-			else
-			{
-				hcl_logbfmt (hcl, HCL_LOG_STDERR, "ERROR: cannot compile object - [%d] %js\n", hcl_geterrnum(hcl), hcl_geterrmsg(hcl));
-			}
-			/* carry on? */
-
-			if (!hcl_isstdreadertty(hcl)) goto oops;
-		}
-		else if (hcl_isstdreadertty(hcl))
-		{
-			/* interactive mode */
-			execute_in_interactive_mode (hcl);
-		}
-	}
-
-	if (!hcl_isstdreadertty(hcl) && hcl_getbclen(hcl) > 0) execute_in_batch_mode (hcl, verbose);
-
-	return 0;
-
-oops:
-	return -1;
-}
-
 static int on_fed_cnode_in_interactive_mode (hcl_t* hcl, hcl_cnode_t* obj)
 {
 	if (hcl_compile(hcl, obj, HCL_COMPILE_CLEAR_CODE | HCL_COMPILE_CLEAR_FNBLK) <= -1) return -1;
@@ -568,7 +499,7 @@ int main (int argc, char* argv[])
 	};
 	static hcl_bopt_t opt =
 	{
-		"l:xv",
+		"l:v",
 		lopt
 	};
 
@@ -576,7 +507,7 @@ int main (int argc, char* argv[])
 	hcl_oow_t heapsize = DEFAULT_HEAPSIZE;
 	int cflags;
 	int verbose = 0;
-	int experimental = 0;
+	/*int experimental = 0;*/
 
 #if defined(HCL_BUILD_DEBUG)
 	const char* dbgopt = HCL_NULL;
@@ -600,9 +531,9 @@ int main (int argc, char* argv[])
 				logopt = opt.arg;
 				break;
 
-			case 'x':
+			/*case 'x':
 				experimental = 1;
-				break;
+				break;*/
 
 			case 'v':
 				verbose = 1;
@@ -744,15 +675,7 @@ int main (int argc, char* argv[])
 	cflags = 0;
 	if (hcl_isstdreadertty(hcl)) cflags = HCL_COMPILE_CLEAR_CODE | HCL_COMPILE_CLEAR_FNBLK;
 
-	if (experimental)
-	{
-		/* this is to test the feed-based reader */
-		if (feed_loop(hcl, xtn, cflags, verbose) <= -1) goto oops;
-	}
-	else
-	{
-		if (main_loop(hcl, xtn, cflags, verbose) <= -1) goto oops;
-	}
+	if (feed_loop(hcl, xtn, cflags, verbose) <= -1) goto oops;
 
 	set_signal_to_default (SIGINT);
 	hcl_close (hcl);
diff --git a/lib/hcl.h b/lib/hcl.h
index 27317b3..eae527b 100644
--- a/lib/hcl.h
+++ b/lib/hcl.h
@@ -2261,10 +2261,6 @@ HCL_EXPORT void hcl_flushio (
 	hcl_t*       hcl
 );
 
-HCL_EXPORT hcl_cnode_t* hcl_read (
-	hcl_t*       hcl
-);
-
 HCL_EXPORT int hcl_print (
 	hcl_t*       hcl,
 	hcl_oop_t    obj
diff --git a/lib/read.c b/lib/read.c
index 472e47b..9f1de4d 100644
--- a/lib/read.c
+++ b/lib/read.c
@@ -1857,379 +1857,6 @@ oops:
 	return HCL_NULL;
 }
 
-static hcl_cnode_t* read_object (hcl_t* hcl)
-{
-	/* this function read an s-expression non-recursively
-	 * by manipulating its own stack. */
-
-	int level = 0, flagv = 0;
-	hcl_cnode_t* obj = HCL_NULL;
-
-	while (1)
-	{
-	redo:
-		switch (TOKEN_TYPE(hcl))
-		{
-			default:
-				hcl_setsynerr (hcl, HCL_SYNERR_ILTOK, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				goto oops;
-
-			case HCL_IOTOK_EOF:
-				hcl_setsynerr (hcl, HCL_SYNERR_EOF, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				goto oops;
-
-			case HCL_IOTOK_INCLUDE:
-				/* TODO: should i limit where #include can be specified?
-				 *       disallow it inside a list literal or an array literal? */
-				GET_TOKEN_WITH_GOTO (hcl, oops);
-				if (TOKEN_TYPE(hcl) != HCL_IOTOK_STRLIT)
-				{
-					hcl_setsynerr (hcl, HCL_SYNERR_STRING, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-					goto oops;
-				}
-				if (begin_include(hcl) <= -1) goto oops;
-				goto redo;
-
-			case HCL_IOTOK_LBRACK: /* [] */
-				flagv = DATA_LIST;
-				LIST_FLAG_SET_CONCODE (flagv, HCL_CONCODE_ARRAY);
-				goto start_list;
-
-			case HCL_IOTOK_BAPAREN: /* #[ */
-				flagv = DATA_LIST;
-				LIST_FLAG_SET_CONCODE (flagv, HCL_CONCODE_BYTEARRAY);
-				goto start_list;
-
-			case HCL_IOTOK_LBRACE: /* { */
-				flagv = DATA_LIST;
-				LIST_FLAG_SET_CONCODE (flagv, HCL_CONCODE_DIC);
-				goto start_list;
-
-			case HCL_IOTOK_QLPAREN: /* #( */
-				flagv = DATA_LIST;
-				LIST_FLAG_SET_CONCODE (flagv, HCL_CONCODE_QLIST);
-				goto start_list;
-
-			case HCL_IOTOK_LPARCOLON: /* (: */
-				flagv = 0;
-				LIST_FLAG_SET_CONCODE (flagv, HCL_CONCODE_MLIST);
-				goto start_list;
-
-			case HCL_IOTOK_LPAREN: /* ( */
-				flagv = 0;
-				LIST_FLAG_SET_CONCODE (flagv, HCL_CONCODE_XLIST);
-			start_list:
-				if (level >= HCL_TYPE_MAX(int))
-				{
-					/* the nesting level has become too deep */
-					hcl_setsynerr (hcl, HCL_SYNERR_NESTING, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-					goto oops;
-				}
-
-				/* push some data to simulate recursion into
-				 * a list literal or an array literal */
-				if (enter_list(hcl, TOKEN_LOC(hcl), flagv) <= -1) goto oops;
-				level++;
-
-				/* read the next token */
-				GET_TOKEN_WITH_GOTO (hcl, oops);
-				goto redo;
-
-			case HCL_IOTOK_DOT:
-				if (level <= 0 || !can_dot_list(hcl))
-				{
-					/* cannot have a period:
-					 *   1. at the top level - not inside ()
-					 *   2. at the beginning of a list
-					 *   3. inside an array, byte-array, dictionary, xlist */
-					hcl_setsynerr (hcl, HCL_SYNERR_DOTBANNED, TOKEN_LOC(hcl), HCL_NULL);
-					goto oops;
-				}
-
-				GET_TOKEN_WITH_GOTO (hcl, oops);
-				goto redo;
-
-			case HCL_IOTOK_COLON:
-				if (level <= 0 || !can_colon_list(hcl))
-				{
-					hcl_setsynerr (hcl, HCL_SYNERR_COLONBANNED, TOKEN_LOC(hcl), HCL_NULL);
-					goto oops;
-				}
-
-				GET_TOKEN_WITH_GOTO (hcl, oops);
-				goto redo;
-
-			case HCL_IOTOK_COMMA:
-				if (level <= 0 || !can_comma_list(hcl))
-				{
-					hcl_setsynerr (hcl, HCL_SYNERR_COMMABANNED, TOKEN_LOC(hcl), HCL_NULL);
-					goto oops;
-				}
-
-				GET_TOKEN_WITH_GOTO (hcl, oops);
-				goto redo;
-
-			case HCL_IOTOK_RPAREN: /* xlist (), qlist #() */
-			case HCL_IOTOK_RBRACK: /* bytearray #[], array[] */
-			case HCL_IOTOK_RBRACE: /* dictionary {} */
-			{
-				static struct
-				{
-					int             closer;
-					hcl_synerrnum_t synerr;
-				} req[] =
-				{
-					{ HCL_IOTOK_RPAREN, HCL_SYNERR_RPAREN }, /* XLIST     ( )  */
-					{ HCL_IOTOK_RPAREN, HCL_SYNERR_RPAREN }, /* MLIST     (: ) */
-					{ HCL_IOTOK_RBRACK, HCL_SYNERR_RBRACK }, /* ARRAY     [ ] */
-					{ HCL_IOTOK_RBRACK, HCL_SYNERR_RBRACK }, /* BYTEARRAY #[ ] */
-					{ HCL_IOTOK_RBRACE, HCL_SYNERR_RBRACE }, /* DIC       { } */
-					{ HCL_IOTOK_RPAREN, HCL_SYNERR_RPAREN }  /* QLIST     #( )  */
-				};
-
-				int oldflagv;
-				int concode;
-
-				if (level <= 0)
-				{
-					hcl_setsynerr (hcl, HCL_SYNERR_UNBALPBB, TOKEN_LOC(hcl), HCL_NULL);
-					goto oops;
-				}
-
-				concode = LIST_FLAG_GET_CONCODE(flagv);
-
-				if (req[concode].closer != TOKEN_TYPE(hcl))
-				{
-					hcl_setsynerr (hcl, req[concode].synerr, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-					goto oops;
-				}
-
-#if 0
-				if ((flagv & QUOTED) || level <= 0)
-				{
-					/* the right parenthesis can never appear while
-					 * 'quoted' is true. 'quoted' is set to false when
-					 * entering a normal list. 'quoted' is set to true
-					 * when entering a quoted list. a quoted list does
-					 * not have an explicit right parenthesis.
-					 * so the right parenthesis can only pair up with
-					 * the left parenthesis for the normal list.
-					 *
-					 * For example, '(1 2 3 ') 5 6)
-					 *
-					 * this condition is triggerred when the first ) is
-					 * met after the second quote.
-					 *
-					 * also it is illegal to have the right parenthesis
-					 * with no opening(left) parenthesis, which is
-					 * indicated by level<=0.
-					 */
-					hcl_setsynerr (hcl, HCL_SYNERR_LPAREN, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-					goto oops;
-				}
-#endif
-				obj = leave_list(hcl, &flagv, &oldflagv);
-
-				level--;
-				break;
-			}
-
-			case HCL_IOTOK_VBAR:
-				if (hcl->c->r.st && (hcl->c->r.st->flagv & DATA_LIST))
-				{
-					hcl_setsynerr (hcl, HCL_SYNERR_VBARBANNED, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-					goto oops;
-				}
-				obj = read_vlist(hcl);
-				break;
-
-			case HCL_IOTOK_NIL:
-				obj = hcl_makecnodenil(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_TRUE:
-				obj = hcl_makecnodetrue(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_FALSE:
-				obj = hcl_makecnodefalse(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_SELF:
-				obj = hcl_makecnodeself(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_SUPER:
-				obj = hcl_makecnodesuper(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_ELLIPSIS:
-				obj = hcl_makecnodeellipsis(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_TRPCOLONS:
-				obj = hcl_makecnodetrpcolons(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_DCSTAR:
-				obj = hcl_makecnodedcstar(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_SMPTRLIT:
-			{
-				hcl_oow_t i;
-				hcl_oow_t v = 0;
-
-				HCL_ASSERT (hcl, TOKEN_NAME_LEN(hcl) >= 3);
-				for (i = 2; i < TOKEN_NAME_LEN(hcl); i++)
-				{
-					HCL_ASSERT (hcl, is_xdigitchar(TOKEN_NAME_CHAR(hcl, i)));
-					v = v * 16 + CHAR_TO_NUM(TOKEN_NAME_CHAR(hcl, i), 16);
-				}
-
-				if (!HCL_IN_SMPTR_RANGE(v))
-				{
-					hcl_setsynerr (hcl, HCL_SYNERR_SMPTRLIT, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-					goto oops;
-				}
-
-				obj = hcl_makecnodesmptrlit(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl), v);
-				break;
-			}
-
-			case HCL_IOTOK_ERRLIT:
-			{
-				hcl_oow_t i;
-				hcl_ooi_t v = 0;
-
-				HCL_ASSERT (hcl, TOKEN_NAME_LEN(hcl) >= 3);
-				for (i = 2; i < TOKEN_NAME_LEN(hcl); i++)
-				{
-					HCL_ASSERT (hcl, is_digitchar(TOKEN_NAME_CHAR(hcl, i)));
-					v = v * 10 + CHAR_TO_NUM(TOKEN_NAME_CHAR(hcl, i), 10);
-
-					if (v > HCL_ERROR_MAX)
-					{
-						hcl_setsynerr (hcl, HCL_SYNERR_ERRLIT, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-						goto oops;
-					}
-				}
-
-				obj = hcl_makecnodeerrlit(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl), v);
-				break;
-			}
-
-			case HCL_IOTOK_CHARLIT:
-				obj = hcl_makecnodecharlit(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl), TOKEN_NAME_CHAR(hcl, 0));
-				break;
-
-			case HCL_IOTOK_NUMLIT:
-				obj = hcl_makecnodenumlit(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_RADNUMLIT:
-				obj = hcl_makecnoderadnumlit(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_FPDECLIT:
-				obj = hcl_makecnodefpdeclit(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			/*
-			case HCL_IOTOK_REAL:
-				obj = hcl_makerealnum(hcl, HCL_IOTOK_RVAL(hcl));
-				break;
-			*/
-
-			case HCL_IOTOK_STRLIT:
-				obj = hcl_makecnodestrlit(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_IDENT:
-				obj = hcl_makecnodesymbol(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-			case HCL_IOTOK_IDENT_DOTTED:
-				obj = hcl_makecnodedsymbol(hcl, TOKEN_LOC(hcl), TOKEN_NAME(hcl));
-				break;
-
-		}
-
-		if (!obj) goto oops;
-
-#if 0
-		/* check if the element is read for a quoted list */
-		while (flagv & QUOTED)
-		{
-			int oldflagv;
-
-			HCL_ASSERT (hcl, level > 0);
-
-			/* if so, append the element read into the quote list */
-			if (chain_to_list(hcl, obj) <= -1) goto oops;
-
-			/* exit out of the quoted list. the quoted list can have one element only. */
-			obj = leave_list(hcl, &flagv, &oldflagv);
-
-			/* one level up toward the top */
-			level--;
-		}
-#endif
-
-		/* check if we are at the top level */
-		if (level <= 0) break; /* yes */
-
-		/* if not, append the element read into the current list.
-		 * if we are not at the top level, we must be in a list */
-		if (chain_to_list(hcl, obj) <= -1) goto oops;
-
-		/* because it has been chained to the list, it belongs to the current stack top.
-		 * mark that obj is not stand-alone by nullifying it. without this, if a jump
-		 * is made to oops, the momory block pointed to by obj may get freed twice. */
-		obj = HCL_NULL;
-
-		clear_comma_colon_flag (hcl);
-
-		/* read the next token */
-		GET_TOKEN_WITH_GOTO (hcl, oops);
-	}
-
-	/* upon exit, we must be at the top level */
-	HCL_ASSERT (hcl, level == 0);
-
-	HCL_ASSERT (hcl, hcl->c->r.st == HCL_NULL);
-	HCL_ASSERT (hcl, obj != HCL_NULL);
-	return obj;
-
-oops:
-	if (obj) hcl_freecnode (hcl, obj);
-
-	/* clean up the reader stack for a list */
-	while (hcl->c->r.st)
-	{
-		hcl_rstl_t* rstl;
-
-		rstl = hcl->c->r.st;
-		hcl->c->r.st = rstl->prev;
-		if (rstl->head) hcl_freecnode (hcl, rstl->head);
-		hcl_freemem (hcl, rstl);
-	}
-
-	return HCL_NULL;
-}
-
-hcl_cnode_t* hcl_read (hcl_t* hcl)
-{
-	HCL_ASSERT (hcl, hcl->c && hcl->c->reader);
-	if (get_token(hcl) <= -1) return HCL_NULL;
-	if (TOKEN_TYPE(hcl) == HCL_IOTOK_EOF)
-	{
-		hcl_seterrnum (hcl, HCL_EFINIS);
-		return HCL_NULL;
-	}
-	return read_object(hcl);
-}
-
 /* ------------------------------------------------------------------------ */
 
 /* TODO: