Here’s some random stuff I found useful after discussing with Phil on “how to start writing ML.”

1. use eval_be to handle binary operations and eval_ue for unary operations.

2. use conv() to handle A.Const_e and A.DataCon_e

3. patMatch() basically handle two cases: “Let val …” and “case … of …” both of these requires pattern matching (that’s why it is there).

4. Before you handling A.Let_e(A.Val_d(…)) in patMatch, it is a good idea to study how A.Case_e() works in patMatch. That should give you some hint on how to proceed.

5. Don’t worry about the A.Id_t(“pat”) or A.Id_t(“patType”) that you found in interp.sml. They are not used at all.

6. http://www.standardml.org/Basis/list-pair.html contains useful function to use when handling A.Tuple_p and A.Record_p in pat_compile. Specifically you need to walk down the tuple/records and perform matching one by one. ListPair is different from List where ListPair walk down two lists simultaneously (your root and p) whereas List do the same thing on one list.

7. Lastly, the assignment statement “x := 3” returns a unit “()”.

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