diff --git a/lib/comp.c b/lib/comp.c
index 0021d75..5a73ae6 100644
--- a/lib/comp.c
+++ b/lib/comp.c
@@ -210,13 +210,13 @@ static int emit_byte_instruction (hcl_t* hcl, hcl_oob_t bc, const hcl_ioloc_t* s
 	{
 		hcl_oow_t newcapa;
 		hcl_oob_t* tmp;
-		hcl_oow_t* tmp2;
+		hcl_dbgl_t* tmp2;
 
 		newcapa = HCL_ALIGN(hcl->code.bc.capa + 1, HCL_BC_BUFFER_ALIGN);
 		tmp = (hcl_oob_t*)hcl_reallocmem(hcl, hcl->code.bc.ptr, HCL_SIZEOF(*tmp) * newcapa);
 		if (HCL_UNLIKELY(!tmp)) return -1;
 
-		tmp2 = (hcl_oow_t*)hcl_reallocmem(hcl, hcl->code.locptr, HCL_SIZEOF(*tmp2) * newcapa);
+		tmp2 = (hcl_dbgl_t*)hcl_reallocmem(hcl, hcl->code.locptr, HCL_SIZEOF(*tmp2) * newcapa);
 		if (HCL_UNLIKELY(!tmp2))
 		{
 			hcl_freemem (hcl, tmp);
@@ -231,10 +231,13 @@ static int emit_byte_instruction (hcl_t* hcl, hcl_oob_t bc, const hcl_ioloc_t* s
 
 	hcl->code.bc.ptr[hcl->code.bc.len] = bc;
 
+/*
 	if (srcloc)
 	{
-		hcl->code.locptr[hcl->code.bc.len] = srcloc->line;
+		hcl->code.locptr[hcl->code.bc.len].fname = srcloc->file;
+		hcl->code.locptr[hcl->code.bc.len].sline = srcloc->line;
 	}
+*/
 
 	hcl->code.bc.len++;
 	return 0;
diff --git a/lib/comp2.c b/lib/comp2.c
index 80c2032..60bc343 100644
--- a/lib/comp2.c
+++ b/lib/comp2.c
@@ -277,13 +277,13 @@ static int emit_byte_instruction (hcl_t* hcl, hcl_oob_t bc, const hcl_ioloc_t* s
 	{
 		hcl_oow_t newcapa;
 		hcl_oob_t* tmp;
-		hcl_oow_t* tmp2;
+		hcl_dbgl_t* tmp2;
 
 		newcapa = HCL_ALIGN(hcl->code.bc.capa + 1, HCL_BC_BUFFER_ALIGN);
 		tmp = (hcl_oob_t*)hcl_reallocmem(hcl, hcl->code.bc.ptr, HCL_SIZEOF(*tmp) * newcapa);
 		if (HCL_UNLIKELY(!tmp)) return -1;
 
-		tmp2 = (hcl_oow_t*)hcl_reallocmem(hcl, hcl->code.locptr, HCL_SIZEOF(*tmp2) * newcapa);
+		tmp2 = (hcl_dbgl_t*)hcl_reallocmem(hcl, hcl->code.locptr, HCL_SIZEOF(*tmp2) * newcapa);
 		if (HCL_UNLIKELY(!tmp2))
 		{
 			hcl_freemem (hcl, tmp);
@@ -300,8 +300,8 @@ static int emit_byte_instruction (hcl_t* hcl, hcl_oob_t bc, const hcl_ioloc_t* s
 
 	if (srcloc)
 	{
-		
-		hcl->code.locptr[hcl->code.bc.len] = srcloc->line;
+		hcl->code.locptr[hcl->code.bc.len].fname = srcloc->file;
+		hcl->code.locptr[hcl->code.bc.len].sline = srcloc->line;
 	}
 
 	hcl->code.bc.len++;
@@ -983,7 +983,7 @@ static int compile_if (hcl_t* hcl, hcl_cnode_t* src)
 
 	SWITCH_TOP_CFRAME (hcl, COP_COMPILE_OBJECT, cond); /* 1 */
 	PUSH_SUBCFRAME (hcl, COP_POST_IF_COND, obj); /* 2 */
-	cf = GET_SUBCFRAME (hcl);
+	cf = GET_SUBCFRAME(hcl);
 	cf->u.post_if.body_pos = -1; /* unknown yet */
 	cf->u.post_if.start_loc = *HCL_CNODE_GET_LOC(src);
 /* TODO: OPTIMIZATION:
@@ -1242,10 +1242,10 @@ static int compile_lambda (hcl_t* hcl, hcl_cnode_t* src, int defun)
 		}
 	}
 
-	PUSH_SUBCFRAME (hcl, COP_EMIT_LAMBDA, HCL_SMOOI_TO_OOP(jump_inst_pos));
+	PUSH_SUBCFRAME (hcl, COP_EMIT_LAMBDA, src);
 
 	cf = GET_SUBCFRAME (hcl);
-	cf->u.lambda.start_loc = *HCL_CNODE_GET_LOC(src);
+	cf->u.lambda.jump_inst_pos = jump_inst_pos;
 
 	if (hcl->option.trait & HCL_TRAIT_INTERACTIVE)
 	{
@@ -1256,9 +1256,10 @@ static int compile_lambda (hcl_t* hcl, hcl_cnode_t* src, int defun)
 	return 0;
 }
 
-static int compile_return (hcl_t* hcl, hcl_cnode_t* src, int mode)
+static int compile_return (hcl_t* hcl, hcl_cnode_t* src, int ret_from_home)
 {
 	hcl_cnode_t* obj, * val;
+	hcl_cframe2_t* cf;
 
 	HCL_ASSERT (hcl, HCL_CNODE_IS_CONS(src));
 	HCL_ASSERT (hcl, HCL_CNODE_IS_SYMBOL_SYNCODED(HCL_CNODE_CONS_CAR(src), HCL_SYNCODE_RETURN) || 
@@ -1293,7 +1294,9 @@ static int compile_return (hcl_t* hcl, hcl_cnode_t* src, int mode)
 
 	SWITCH_TOP_CFRAME (hcl, COP_COMPILE_OBJECT, val);
 
-	PUSH_SUBCFRAME (hcl, COP_EMIT_RETURN, HCL_SMOOI_TO_OOP(mode));
+	PUSH_SUBCFRAME (hcl, COP_EMIT_RETURN, src);
+	cf = GET_SUBCFRAME(hcl);
+	cf->u._return.from_home = ret_from_home;
 
 	return 0;
 }
@@ -1447,7 +1450,7 @@ static int compile_while (hcl_t* hcl, hcl_cnode_t* src, int next_cop)
 
 	SWITCH_TOP_CFRAME (hcl, COP_COMPILE_OBJECT, cond); /* 1 */
 	PUSH_SUBCFRAME (hcl, next_cop, obj); /* 2 */
-	cf = GET_SUBCFRAME (hcl);
+	cf = GET_SUBCFRAME(hcl);
 	cf->u.post_while.cond_pos = cond_pos;
 	cf->u.post_while.body_pos = -1; /* unknown yet*/
 	cf->u.post_while.start_loc = *HCL_CNODE_GET_LOC(src);
@@ -2361,13 +2364,12 @@ static int compile_qlist (hcl_t* hcl)
 	else
 	{
 		hcl_cnode_t* car, * cdr;
-		hcl_ooi_t oldidx;
 
 		if (!HCL_CNODE_IS_CONS(oprnd))
 		{
 			/* the last element after . */
 			SWITCH_TOP_CFRAME (hcl, COP_COMPILE_OBJECT, oprnd);
-			PUSH_SUBCFRAME (hcl, COP_EMIT_POP_INTO_CONS_CDR, HCL_NULL);
+			PUSH_SUBCFRAME (hcl, COP_EMIT_POP_INTO_CONS_CDR, oprnd); /* TODO: can i pass the location of the closing )? */
 		}
 		else
 		{
@@ -2378,12 +2380,12 @@ static int compile_qlist (hcl_t* hcl)
 			if (cdr)
 			{
 				PUSH_SUBCFRAME (hcl, COP_COMPILE_QLIST, cdr); /* 3 */
-				PUSH_SUBCFRAME (hcl, COP_EMIT_POP_INTO_CONS, HCL_NULL); /* 2 */
+				PUSH_SUBCFRAME (hcl, COP_EMIT_POP_INTO_CONS, oprnd); /* 2 */
 			}
 			else
 			{
 				/* the last element */
-				PUSH_SUBCFRAME (hcl, COP_EMIT_POP_INTO_CONS_END, HCL_NULL); /* 2 */
+				PUSH_SUBCFRAME (hcl, COP_EMIT_POP_INTO_CONS_END, oprnd); /* 2 */
 			}
 		}
 	}
@@ -2479,7 +2481,7 @@ static HCL_INLINE int subcompile_elif (hcl_t* hcl)
 
 	SWITCH_TOP_CFRAME (hcl, COP_COMPILE_OBJECT, cond); /* 1 */
 	PUSH_SUBCFRAME (hcl, COP_POST_IF_COND, obj); /* 2 */
-	cf = GET_SUBCFRAME (hcl);
+	cf = GET_SUBCFRAME(hcl);
 	cf->u.post_if.body_pos = -1; /* unknown yet */
 	cf->u.post_if.start_loc = *HCL_CNODE_GET_LOC(src);
 
@@ -2953,9 +2955,9 @@ static HCL_INLINE int emit_pop_into_cons (hcl_t* hcl, int cmd)
 	HCL_ASSERT (hcl, cf->opcode == COP_EMIT_POP_INTO_CONS ||
 	                 cf->opcode == COP_EMIT_POP_INTO_CONS_END ||
 	                 cf->opcode == COP_EMIT_POP_INTO_CONS_CDR);
-	HCL_ASSERT (hcl, cf->operand == HCL_NULL);
+	HCL_ASSERT (hcl, cf->operand != HCL_NULL);
 
-	n = emit_byte_instruction (hcl, cmd, HCL_NULL);
+	n = emit_byte_instruction (hcl, cmd, HCL_CNODE_GET_LOC(cf->operand));
 
 	POP_CFRAME (hcl);
 	return n;
@@ -2969,9 +2971,9 @@ static HCL_INLINE int emit_lambda (hcl_t* hcl)
 
 	cf = GET_TOP_CFRAME(hcl);
 	HCL_ASSERT (hcl, cf->opcode == COP_EMIT_LAMBDA);
-	HCL_ASSERT (hcl, HCL_OOP_IS_SMOOI(cf->operand));
+	HCL_ASSERT (hcl, cf->operand != HCL_NULL);
 
-	jip = HCL_OOP_TO_SMOOI(cf->operand);
+	jip = cf->u.lambda.jump_inst_pos;
 
 	if (hcl->option.trait & HCL_TRAIT_INTERACTIVE) 
 		lfsize = hcl->code.lit.len - hcl->c->blk.info[hcl->c->blk.depth].lfbase;
@@ -2987,16 +2989,16 @@ static HCL_INLINE int emit_lambda (hcl_t* hcl)
  	{
 		/* no body in lambda - (lambda (a b c)) */
 /* TODO: is this correct??? */
-		if (emit_byte_instruction(hcl, HCL_CODE_PUSH_NIL, HCL_NULL) <= -1) return -1;
+		if (emit_byte_instruction(hcl, HCL_CODE_PUSH_NIL, HCL_CNODE_GET_LOC(cf->operand)) <= -1) return -1;
 		block_code_size++;
 	}
 
-	if (emit_byte_instruction(hcl, HCL_CODE_RETURN_FROM_BLOCK, HCL_NULL) <= -1) return -1;
+	if (emit_byte_instruction(hcl, HCL_CODE_RETURN_FROM_BLOCK, HCL_CNODE_GET_LOC(cf->operand)) <= -1) return -1;
 	block_code_size++;
 
 	if (block_code_size > MAX_CODE_JUMP * 2)
 	{
-		hcl_setsynerrbfmt (hcl, HCL_SYNERR_BLKFLOOD, &cf->u.lambda.start_loc, HCL_NULL, "code too big - size %zu", block_code_size);
+		hcl_setsynerrbfmt (hcl, HCL_SYNERR_BLKFLOOD, HCL_CNODE_GET_LOC(cf->operand), HCL_NULL, "code too big - size %zu", block_code_size);
 		return -1;
 	}
 	patch_long_jump (hcl, jip, block_code_size);
@@ -3030,9 +3032,9 @@ static HCL_INLINE int emit_return (hcl_t* hcl)
 
 	cf = GET_TOP_CFRAME(hcl);
 	HCL_ASSERT (hcl, cf->opcode == COP_EMIT_RETURN);
-	HCL_ASSERT (hcl, HCL_OOP_IS_SMOOI(cf->operand));
+	HCL_ASSERT (hcl, cf->operand != HCL_NULL);
 
-	n = emit_byte_instruction(hcl, (HCL_OOP_TO_SMOOI(cf->operand) == 0? HCL_CODE_RETURN_FROM_BLOCK: HCL_CODE_RETURN_STACKTOP), HCL_NULL);
+	n = emit_byte_instruction(hcl, (cf->u._return.from_home? HCL_CODE_RETURN_STACKTOP: HCL_CODE_RETURN_FROM_BLOCK), HCL_CNODE_GET_LOC(cf->operand));
 
 	POP_CFRAME (hcl);
 	return n;
diff --git a/lib/exec.c b/lib/exec.c
index 2c08656..c10c8de 100644
--- a/lib/exec.c
+++ b/lib/exec.c
@@ -3649,6 +3649,8 @@ hcl_oop_t hcl_execute (hcl_t* hcl)
 	func = make_function(hcl, hcl->code.lit.len, hcl->code.bc.ptr, hcl->code.bc.len);
 	if (HCL_UNLIKELY(!func)) return HCL_NULL;
 
+/* TODO: copy the debug information as well into the dbgi field of the function object. */
+
 	/* pass nil for the home context of the initial function */
 	fill_function_data (hcl, func, 0, 0, (hcl_oop_context_t)hcl->_nil, hcl->code.lit.arr->slot, hcl->code.lit.len);
 
diff --git a/lib/hcl-prv.h b/lib/hcl-prv.h
index b2a5ed8..7b2818e 100644
--- a/lib/hcl-prv.h
+++ b/lib/hcl-prv.h
@@ -47,7 +47,7 @@
 #define HCL_ENABLE_FLTFMT
 
 #if defined(HCL_BUILD_DEBUG)
-#define HCL_DEBUG_LEXER 1
+/*#define HCL_DEBUG_LEXER 1*/
 #define HCL_DEBUG_VM_PROCESSOR 1
 #define HCL_DEBUG_VM_EXEC 1
 /*#define HCL_PROFILE_VM 1*/
@@ -349,10 +349,15 @@ struct hcl_cframe2_t
 
 		struct
 		{
-			hcl_ioloc_t start_loc;
+			hcl_oow_t jump_inst_pos;
 			hcl_ooi_t lfbase_pos;
 			hcl_ooi_t lfsize_pos;
 		} lambda;
+
+		struct
+		{
+			int from_home;
+		} _return;
 	} u;
 };
 typedef struct hcl_cframe2_t hcl_cframe2_t;
diff --git a/lib/hcl.h b/lib/hcl.h
index 5838577..f8cbe3b 100644
--- a/lib/hcl.h
+++ b/lib/hcl.h
@@ -1373,6 +1373,14 @@ struct hcl_synerr_t
 	} tgt;
 };
 
+
+typedef struct hcl_dbgl_t hcl_dbgl_t;
+struct hcl_dbgl_t
+{
+	const hcl_ooch_t* fname; /* file name */
+	hcl_oow_t sline; /* source line in the file */
+};
+
 #if defined(HCL_INCLUDE_COMPILER)
 typedef struct hcl_compiler_t hcl_compiler_t;
 typedef struct hcl_cnode_t hcl_cnode_t;
@@ -1567,7 +1575,8 @@ struct hcl_t
 		} lit;
 
 		/* array that hold the location of the byte code emitted */
-		hcl_oow_t* locptr;
+
+		hcl_dbgl_t* locptr;
 	} code;
 
 	/* == PRINTER == */
diff --git a/lib/read.c b/lib/read.c
index 24c65a8..fb473d8 100644
--- a/lib/read.c
+++ b/lib/read.c
@@ -1299,7 +1299,7 @@ static const hcl_ooch_t* add_io_name (hcl_t* hcl, const hcl_oocs_t* name)
 	hcl_iolink_t* link;
 	hcl_ooch_t* ptr;
 
-	link = (hcl_iolink_t*)hcl_callocmem (hcl, HCL_SIZEOF(*link) + HCL_SIZEOF(hcl_ooch_t) * (name->len + 1));
+	link = (hcl_iolink_t*)hcl_callocmem(hcl, HCL_SIZEOF(*link) + HCL_SIZEOF(hcl_ooch_t) * (name->len + 1));
 	if (HCL_UNLIKELY(!link)) return HCL_NULL;
 
 	ptr = (hcl_ooch_t*)(link + 1);
diff --git a/lib/read2.c b/lib/read2.c
index db5c558..45a1e79 100644
--- a/lib/read2.c
+++ b/lib/read2.c
@@ -1319,10 +1319,10 @@ static int begin_include (hcl_t* hcl)
 	hcl_ioinarg_t* arg;
 	const hcl_ooch_t* io_name;
 
-	io_name = add_io_name (hcl, TOKEN_NAME(hcl));
-	if (!io_name) return -1;
+	io_name = add_io_name(hcl, TOKEN_NAME(hcl));
+	if (HCL_UNLIKELY(!io_name)) return -1;
 
-	arg = (hcl_ioinarg_t*)hcl_callocmem (hcl, HCL_SIZEOF(*arg));
+	arg = (hcl_ioinarg_t*)hcl_callocmem(hcl, HCL_SIZEOF(*arg));
 	if (HCL_UNLIKELY(!arg)) goto oops;
 
 	arg->name = io_name;