Data commit

Task/First-class-environments/D/first-class-environments.d

@@ -0,0 +1,28 @@
+import std.stdio, std.algorithm, std.range, std.array;
+
+struct Prop {
+    int[string] data;
+    ref opDispatch(string s)() pure nothrow {
+        return data[s];
+    }
+}
+
+immutable code = `
+writef("% 4d", e.seq);
+if (e.seq != 1) {
+    e.cnt++;
+    e.seq = (e.seq & 1) ? 3 * e.seq + 1 : e.seq / 2;
+}`;
+
+void main() {
+    auto envs = 12.iota.map!(i => Prop(["cnt": 0, "seq": i+1])).array;
+
+    while (envs.any!(env => env.seq > 1)) {
+        foreach (e; envs) {
+            mixin(code);
+        }
+        writeln;
+    }
+
+    writefln("Counts:\n%(% 4d%)", envs.map!(env => env.cnt));
+}