Add test for the various aspects of first class dicts.

jscomp/test/FirstClassDicts.res

@@ -0,0 +1,33 @@
+module CreateAndLookup = {
+  type myDict = {name?: string, mutable anyOtherField?: int}
+
+  let test_create: myDict = {name: "hello", something: 5}
+
+  let test_lookup = (d: myDict) => d.something = Some(10)
+}
+
+
+module Update = {
+  type myDict = {name?: string, mutable anyOtherField?: int}
+
+  let test_update = (d: myDict) => d.something = Some(10)
+}
+
+
+module PatternMatching = {
+  type myDict = {name?: string, anyOtherField?: int}
+
+  let tst1 = (d: myDict) =>
+    switch d {
+    | {name: n, something: i} => String.length(n) + i
+    | {name: n} => String.length(n)
+    | {something: i} => i
+    | _ => 0
+    }
+
+  let tst2 = (d: myDict) =>
+    switch d {
+    | {name: _, a: i, b: j} => i + j
+    | _ => 0
+    }
+}