+/** fac1 = "(" expr ")" */
+let fac1 = circumfix((x : TokenMatcheePair)=>
+thenDo(thenDo(thenDo(tk.toSome(x), tLParen), expr), tRParen), "fac1");
+
+let fac2 = tInt;
+
+let fac = orDo(fac1, fac2);
+
+
+
+/**
+ *
+ * term1 = fac (MUL | DIV) fac
+ */
+
+let term1 = midfix((x : TokenMatcheePair)=>
+ thenDo(thenDo(thenDo(tk.toSome(x), fac), orDo(tMul,tDiv)), fac), "term1");
+
+
+/**
+ *
+ * term2 = int MUL int
+ */
+let term2 = fac;
+
+/**
+ * term = term1 | term2
+ */
+let term = orDo(term1, term2);
+
+
+/**
+ *
+ * expr1 = term ADD term
+ */
+let expr1 = midfix((x : TokenMatcheePair)=>
+ thenDo(thenDo(thenDo(tk.toSome(x), term), orDo(tAdd,tSub)), term), "expr1");
+/**
+ * expr2 = term
+ */
+let expr2 = term;
+