Created grammar for simple version of the language

Lexer.x

+--tokens
+
+.in
+.out
\ No newline at end of file

Parser.y

+Prog : .in SetNames .out SetFuncCalls
+
+SetNames : SetName
+    | SetName, SetNames
+    
+VarNames : VarName
+    | VarName, VarNames
+
+SetSetFuncCalls : SetFuncCall    {[SetFuncCall]}
+    | SetFuncCall; SetFuncCalls   {SetFuncCall:SetFuncCalls}
+
+SetFuncCall : filter '['SetName']' (Func)
+
+Func : \'('VarNames')' -> Expr
+\(r) -> r[1] == "hello"
+
+Expr : Expr == Expr
+    | Expr'['Nat']'
+    | String
+    | VarName
+    | Record
+    | true
+    | false
+
+
+Record : '['Exprs']'
+Exprs : Expr
+    | Expr','Exprs