Andl.Net – making progress

Working surprisingly well. As purely a query language, it has:

  • Equals, subset, distinct
  • Where
  • Select (combines Rename, Project, Extend)
  • Set ops: union, minus, intersect, symdiff
  • Join and Antijoin
  • Order by (for export purposes)
  • Skip Take

The code looks like this:

      class TT1 : NdlTuple<TT1> {
      public string A2;
      public int A1;
      public decimal A3;
      public static TT1[] R1() {
        return new TT1[] {
          new TT1 { A1 = 42, A2 = "hello", A3 = 1.2m },
          new TT1 { A1 = 42, A2 = "world", A3 = 1.2m },
        };
      }
      public static NdlRelation<TT1> NDR_1() {
        return new NdlRelation<TT1>(R1());
      }
    }

    var v1 = TT1.NDR_1();
    var v2 = v1.Where(t => t.A1 == 42);
    var v3 = v2.Select(t => new TT2 { A1 = t.A1, A2 = "constant", A3 = t.A3 });

I’m making heavy use of NUnit and finding plenty of bugs. No updates yet; no data import; no aggregation; no while/recursion; no ordered queries. But it all seems surprisingly possible, even without a lot of help from the compiler. And much easier than writing compilers.

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