Fixed ambiguity for if else

1 files changed, 15 insertions, 1 deletions

diff --git a/source/mod_student/parser.mly b/source/mod_student/parser.mly
index 2665861..4d1a142 100644
--- a/source/mod_student/parser.mly
+++ b/source/mod_student/parser.mly
@@ -195,11 +195,25 @@ statement:
         {STMT_VarDecl { var=var;init=init } }
     | WHILE cond=expression body=statement 
         { STMT_While {loc=mkLocation $startpos;cond=cond;body=body } }
-    | IF cond=expression then_branch=statement else_branch=option(preceded(ELSE,statement)) (*Menhir attempts to mimic ocamlyacc’s specification, that is, to resolve shift/reduce conflicts in favor of shifting*)
+    | IF cond=expression then_branch=statement2 else_branch=option(preceded(ELSE,statement)) (*Menhir attempts to mimic ocamlyacc’s specification, that is, to resolve shift/reduce conflicts in favor of shifting*)
         { STMT_If {loc=mkLocation $startpos;cond=cond;then_branch=then_branch;
           else_branch=else_branch } }
     | head=option_var_decl COMMA tail=separated_nonempty_list(COMMA, option_var_decl) ASSIGN call=call
         { STMT_MultiVarDecl {loc=mkLocation $startpos; vars= head::tail; init=call } }
+statement2:
+    | left=lvalue ASSIGN right=expression  { STMT_Assign {loc=mkLocation $startpos;
+                              lhs=left;rhs=right} }
+    | block=statement_block {STMT_Block block }
+    | call=call {STMT_Call call }
+    | var=var_decl init=option(preceded(ASSIGN,expression))
+        {STMT_VarDecl { var=var;init=init } }
+    | WHILE cond=expression body=statement2 
+        { STMT_While {loc=mkLocation $startpos;cond=cond;body=body } }
+    | IF cond=expression then_branch=statement2 ELSE else_branch=statement2 
+        { STMT_If {loc=mkLocation $startpos;cond=cond;then_branch=then_branch;
+          else_branch=Some else_branch } }
+    | head=option_var_decl COMMA tail=separated_nonempty_list(COMMA, option_var_decl) ASSIGN call=call
+        { STMT_MultiVarDecl {loc=mkLocation $startpos; vars= head::tail; init=call } }
 return_stmt:
     | RETURN values=separated_list(COMMA,expression)
         { [STMT_Return { loc=mkLocation $startpos; values=values }] }