add left/child requirement

2 files changed, 18 insertions, 4 deletions

diff --git a/include/lexer/enum_type.h b/include/lexer/enum_type.h
index 9de3dc7..e1c5b6f 100644
--- a/include/lexer/enum_type.h
+++ b/include/lexer/enum_type.h
@@ -25,4 +25,11 @@ enum guard_type
     GUARD_STRONG,
 };
 
+enum child_existance_type
+{
+    NOT_EXIST,
+    OPTIONAL,
+    EXIST,
+};
+
 }
diff --git a/include/lexer/symbol_property.h b/include/lexer/symbol_property.h
index 3d85623..2e94cf7 100644
--- a/include/lexer/symbol_property.h
+++ b/include/lexer/symbol_property.h
@@ -15,6 +15,12 @@ public:
     int operand_number = 0;
     bool continuable = true;
     int pivot_priority = -1;
+
+    // require: MUST
+    // accept: optional, but if it doesn't accept, but there is indeed a child, then error
+    child_existance_type left;
+    child_existance_type right;
+
     enum_token_type enum_type = TEXT;
 };
 
@@ -28,10 +34,11 @@ unordered_map<string, T_property> symbol_property = {
     {")",    {.continuable = false, .enum_type = RIGHT_BRACKET}},
 
     // operator
-    {"&",    {.operand_number = 1, .continuable = true,  .pivot_priority = 1000, .enum_type = ASYNC}},
-    {"|",    {.operand_number = 1, .continuable = true,  .pivot_priority = 100,  .enum_type = PIPE}},
-    {"&&",   {.operand_number = 1, .continuable = true,  .pivot_priority = 1000, .enum_type = LOGIC_AND}},
-    {"||",   {.operand_number = 1, .continuable = true,  .pivot_priority = 1000, .enum_type = LOGIC_OR}},
+    {"&",    {.operand_number = 1, .continuable = true, .pivot_priority = 1000, .left = EXIST,     .right = NOT_EXIST, .enum_type = ASYNC}},
+    {"|",    {.operand_number = 1, .continuable = true, .pivot_priority = 100,  .left = EXIST,     .right = EXIST,     .enum_type = PIPE}},
+    {"&&",   {.operand_number = 1, .continuable = true, .pivot_priority = 1000, .left = EXIST,     .right = EXIST,     .enum_type = LOGIC_AND}},
+    {"||",   {.operand_number = 1, .continuable = true, .pivot_priority = 1000, .left = EXIST,     .right = EXIST,     .enum_type = LOGIC_OR}},
+
 };
     
 }