From 35944a5565c0708e5c082fd4ad234ae1890ae68e Mon Sep 17 00:00:00 2001
From: Wang Renxin <hellotony521@qq.com>
Date: Sat, 10 Mar 2018 14:06:34 +0800
Subject: [PATCH] *fixed a stepping bug in the `if` statement.

---
 HISTORY         | 1 +
 core/my_basic.c | 7 ++++++-
 core/my_basic.h | 1 +
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/HISTORY b/HISTORY
index fc3785b..2bf5235 100755
--- a/HISTORY
+++ b/HISTORY
@@ -1,5 +1,6 @@
 Mar. 9 2018
 Fixed a GC bug with ranged FOR loop
+Fixed a stepping bug in the IF statement
 
 Jan. 15 2018
 Fixed a crash bug with invalid collection index
diff --git a/core/my_basic.c b/core/my_basic.c
index c246e81..79f1467 100755
--- a/core/my_basic.c
+++ b/core/my_basic.c
@@ -293,6 +293,7 @@ MBCONST static const char* const _ERR_DESC[] = {
 	"Operation failed",
 	"Operator expected",
 	"Assign operator expected",
+	"THEN statement expected",
 	"ELSE statement expected",
 	"ENDIF statement expected",
 	"TO statement expected",
@@ -15654,7 +15655,11 @@ _elseif:
 		skip = true;
 
 		if(!_IS_FUNC(obj, _core_then)) {
-			_handle_error_on_obj(s, SE_RN_INTEGER_EXPECTED, s->source_file, DON(ast), MB_FUNC_ERR, _exit, result);
+			if(ast->prev && _IS_FUNC(ast->prev->data, _core_then)) {
+				ast = ast->prev;
+			} else {
+				_handle_error_on_obj(s, SE_RN_THEN_EXPECTED, s->source_file, DON(ast), MB_FUNC_ERR, _exit, result);
+			}
 		}
 
 		if(ast && ast->next && _IS_EOS(ast->next->data)) {
diff --git a/core/my_basic.h b/core/my_basic.h
index db4b318..8cfa9b2 100755
--- a/core/my_basic.h
+++ b/core/my_basic.h
@@ -434,6 +434,7 @@ typedef enum mb_error_e {
 	SE_RN_OPERATION_FAILED,
 	SE_RN_OPERATOR_EXPECTED,
 	SE_RN_ASSIGN_OPERATOR_EXPECTED,
+	SE_RN_THEN_EXPECTED,
 	SE_RN_ELSE_EXPECTED,
 	SE_RN_ENDIF_EXPECTED,
 	SE_RN_TO_EXPECTED,