diff --git a/bin/hcl.c b/bin/hcl.c
index 65f743b..8f08fe4 100644
--- a/bin/hcl.c
+++ b/bin/hcl.c
@@ -641,10 +641,8 @@ static int feed_loop (hcl_t* hcl, xtn_t* xtn, int verbose)
 				print_error (hcl, "failed to feed");
 				if (len > 0) show_prompt (hcl, 0);
 
-				/* clear the compiled code but not executed yet */
-				hcl_clearcode(hcl);
-				hcl_clearfnblks(hcl);
-				xtn->feed.ncompexprs = 0;
+				hcl_clearcode(hcl); /* clear the compiled code but not executed yet in advance */
+				xtn->feed.ncompexprs = 0; /* next time, hcl_compile() is supposed to clear code and fnblks */
 			}
 			else
 			{
diff --git a/lib/comp.c b/lib/comp.c
index cb5ed3b..4aac594 100644
--- a/lib/comp.c
+++ b/lib/comp.c
@@ -1242,12 +1242,6 @@ static void pop_fnblk (hcl_t* hcl)
 	}
 }
 
-void hcl_clearfnblks (hcl_t* hcl)
-{
-	while (hcl->c->fnblk.depth >= 0) pop_fnblk (hcl);
-	HCL_ASSERT (hcl, hcl->c->fnblk.depth == -1);
-}
-
 /* ========================================================================= */
 static HCL_INLINE int _insert_cframe (hcl_t* hcl, hcl_ooi_t index, int opcode, hcl_cnode_t* operand)
 {
@@ -5897,7 +5891,8 @@ int hcl_compile (hcl_t* hcl, hcl_cnode_t* obj, int flags)
 		 * in the interactive mode, the information doesn't have
 		 * to get carried over.
 		 */
-		hcl_clearfnblks (hcl);
+		while (hcl->c->fnblk.depth >= 0) pop_fnblk (hcl);
+		HCL_ASSERT (hcl, hcl->c->fnblk.depth == -1);
 		/* it will be recreated below */
 	}
 	if (flags & HCL_COMPILE_CLEAR_CODE) hcl_clearcode (hcl);
@@ -6203,9 +6198,6 @@ int hcl_compile (hcl_t* hcl, hcl_cnode_t* obj, int flags)
 	HCL_ASSERT (hcl, hcl->c->fnblk.depth == 0); /* ensure the virtual function block be the only one left */
 	hcl->code.ngtmprs = hcl->c->fnblk.info[0].tmprcnt; /* populate the number of global temporary variables */
 
-	/* TODO: delete all !defined(CLEAR_FNBLK_ALWAYS) code
-	 *       keep only defined(CLEAR_FNBLK_ALWAYS) code.
-	 *       not clearing the top fnblk for the reuse doesn't look very beneficial */
 #if defined(CLEAR_FNBLK_ALWAYS)
 	pop_fnblk (hcl);
 	HCL_ASSERT (hcl, hcl->c->tv.s.len == 0);
diff --git a/lib/hcl.h b/lib/hcl.h
index a5d1e39..18ac7af 100644
--- a/lib/hcl.h
+++ b/lib/hcl.h
@@ -1318,7 +1318,7 @@ struct hcl_io_udiarg_t
 	void* handle;
 
 	/**
-	 * [OUT] place data here for #HCL_IO_READ
+	 * [OUT] place data in c for #HCL_IO_READ and in d for #HCL_IO_READ_BYTES
 	 */
 	union {
 		hcl_ooch_t  c[2048]; /* TODO: resize this if necessary */
@@ -1330,6 +1330,12 @@ struct hcl_io_udiarg_t
 	 * #HCL_IO_READ or #HCL_IO_READ_BYTES
 	 */
 	hcl_oow_t xlen;
+
+	/**
+	 * Internal use only. Don't touch these.
+	 */
+	hcl_oow_t pos;
+	int is_byte;
 };
 
 typedef struct hcl_io_udoarg_t hcl_io_udoarg_t;
@@ -2568,10 +2574,6 @@ HCL_EXPORT void hcl_clearcode (
 	hcl_t* hcl
 );
 
-HCL_EXPORT void hcl_clearfnblks (
-	hcl_t* hcl
-);
-
 #if defined(HCL_HAVE_INLINE)
 static HCL_INLINE hcl_code_t* hcl_getcode (hcl_t* hcl) { return &hcl->code; }
 static HCL_INLINE hcl_oob_t* hcl_getbcptr (hcl_t* hcl) { return hcl->code.bc.ptr; }
diff --git a/lib/prim.c b/lib/prim.c
index 7a57d15..e6d56d0 100644
--- a/lib/prim.c
+++ b/lib/prim.c
@@ -215,15 +215,77 @@ static hcl_pfrc_t pf_sprintf (hcl_t* hcl, hcl_mod_t* mod, hcl_ooi_t nargs)
 
 /* ------------------------------------------------------------------------- */
 
+
+static int get_udi_char (hcl_t* hcl, hcl_ooch_t* ch)
+{
+	if (hcl->io.udi_arg.pos >= hcl->io.udi_arg.xlen)
+	{
+		hcl->io.udi_arg.pos = 0;
+		hcl->io.udi_arg.xlen = 0;
+		if (hcl->io.udi_rdr(hcl, HCL_IO_READ, &hcl->io.udi_arg) <= -1) return -1;
+		if (hcl->io.udi_arg.xlen <= 0) return 0; /* EOF */
+		hcl->io.udi_arg.is_byte = 0;
+	}
+
+
+	if (hcl->io.udi_arg.is_byte)
+	{
+		/* TODO: set error */
+		return -1;
+	}
+
+	*ch = hcl->io.udi_arg.buf.c[hcl->io.udi_arg.pos++];
+	return 1;
+}
+
+static int get_udi_byte (hcl_t* hcl, hcl_uint8_t* bt)
+{
+	if (hcl->io.udi_arg.pos >= hcl->io.udi_arg.xlen)
+	{
+		hcl->io.udi_arg.pos = 0;
+		hcl->io.udi_arg.xlen = 0;
+		if (hcl->io.udi_rdr(hcl, HCL_IO_READ_BYTES, &hcl->io.udi_arg) <= -1) return -1;
+		if (hcl->io.udi_arg.xlen <= 0) return 0; /* EOF */
+		hcl->io.udi_arg.is_byte = 1;
+	}
+
+	if (!hcl->io.udi_arg.is_byte)
+	{
+		/* TODO: set error */
+		return -1;
+	}
+
+	*bt = hcl->io.udi_arg.buf.b[hcl->io.udi_arg.pos++];
+	return 1;
+}
+
 static hcl_pfrc_t pf_getbyte (hcl_t* hcl, hcl_mod_t* mod, hcl_ooi_t nargs)
 {
+	hcl_oop_t v;
+	hcl_uint8_t bt;
+	int n;
+
+	n = get_udi_byte(hcl, &bt);
+	if (n <= -1) return HCL_PF_FAILURE;
+
+	/* return nil on EOF, or the actual character read */
+	v = (n == 0)? hcl->_nil: HCL_SMOOI_TO_OOP(bt);
+	HCL_STACK_SETRET (hcl, nargs, v);
 	return HCL_PF_SUCCESS;
 }
 
 static hcl_pfrc_t pf_getch (hcl_t* hcl, hcl_mod_t* mod, hcl_ooi_t nargs)
 {
-	/*getchar(;)
-	HCL_STACK_SETRET (hcl, nars, v);*/
+	hcl_oop_t v;
+	hcl_ooch_t ch;
+	int n;
+
+	n = get_udi_char(hcl, &ch);
+	if (n <= -1) return HCL_PF_FAILURE;
+
+	/* return nil on EOF, or the actual character read */
+	v = (n == 0)? hcl->_nil: HCL_CHAR_TO_OOP(ch);
+	HCL_STACK_SETRET (hcl, nargs, v);
 	return HCL_PF_SUCCESS;
 }