September 2017 Update

Task/Hash-join/Zkl/hash-join.zkl

@@ -0,0 +1,24 @@
+ageName:=T(27,"Jonah", 18,"Alan", 28,"Glory", 18,"Popeye", 28,"Alan");
+nameNemesis:=T("Jonah","Whales", "Jonah","Spiders", "Alan","Ghosts",
+      "Alan","Zombies", "Glory","Buffy");
+
+fcn addAN(age,name,d){  // keys are names, values are ( (age,...),() )
+   if (r:=d.find(name)) d[name] = T(r[0].append(age),r[1]);
+   else d.add(name,T(T(age),T));
+   d	// return d so pump will use that as result for assignment
+}
+fcn addNN(name,nemesis,d){ // values-->( (age,age...), (nemesis,...) )
+   if (r:=d.find(name)){
+      ages,nemesises := r;
+      d[name] = T(ages,nemesises.append(nemesis));
+   }
+}
+    // Void.Read --> take existing i, read next one, pass both to next function
+var d=ageName.pump(Void,Void.Read,T(addAN,Dictionary()));
+nameNemesis.pump(Void,Void.Read,T(addNN,d));
+
+d.println();  // the union of the two tables
+d.keys.sort().pump(Console.println,'wrap(name){  //pretty print the join
+   val:=d[name]; if (not val[1])return(Void.Skip);
+   String(name,":",d[name][1].concat(","));
+})