Add find_function to library_d3.js, start re-implementing SelectionOr…

…Transition wrapper

source/web/d3/library_d3.js

@@ -2,6 +2,12 @@ var D3Library = {
   $emp_d3: {objects: {}, counts: {}, next_id:0},
   get_emp_d3: function() {
     return this.emp_d3;
+  },
+  find_function: function(sel) {
+    return (window["d3"][sel] === "function") ? window["d3"][sel] :
+           (window["emp"][sel] === "function") ? window["emp"][sel] :
+           (window[sel] === "function") ? window[sel] :
+           sel;
   }
 };
 

source/web/d3/selection.h

@@ -0,0 +1,102 @@
+//  This file is part of Empirical, https://github.com/devosoft/Empirical
+//  Copyright (C) Michigan State University, 2016-2020.
+//  Released under the MIT Software license; see doc/LICENSE
+
+#ifndef __SELECTION_H__
+#define __SELECTION_H__
+
+#include "d3_init.h"
+
+#include <iostream>
+#include <string>
+#include <typeinfo>
+#include <map>
+#include <array>
+
+#include "../../base/assert.h"
+#include "../js_utils.h"
+#include "../JSWrap.h"
+
+namespace D3 {
+
+namespace internal {
+
+  /// You probably never want to instantiate this class. Its sole purpose is to hold code for
+  /// methods that are common to selections and transitions.
+  ///
+  /// Developer note: It's also handy if you want to allow a function to accept either a selection
+  /// or transition. This is a good idea any time you are only using methods that are applicable to
+  /// either, and the person calling the function may want to animate its results.
+  template <typename DERIVED>
+  class SelectionOrTransition : public D3_Base {
+  public:
+
+      SelectionOrTransition() { ; }
+      SelectionOrTransition(int id) : D3_Base(id) { ; }
+      SelectionOrTransition(const SelectionOrTransition<DERIVED> & s) : D3_Base(s) { ; }
+
+      /// Create a new selection/transition containing the first element matching the
+      /// [selector] string that are within this current selection/transition
+      DERIVED Select(const std::string & selector) const {
+        const int new_id = NextD3ID();
+
+        EM_ASM({
+          const id = $0;
+          const selector = UTF8ToString($1);
+          const new_id = $2;
+          var new_selection = emp_d3.objects[id].select(selector);
+          emp_d3.objects[new_id] = new_selection;
+        }, this->id, selector.c_str(), new_id);
+
+        return DERIVED(new_id);
+      }
+
+      /// Create a new selection/transition containing all elements matching the [selector]
+      /// string that are within this current selection/transition
+      DERIVED SelectAll(const std::string & selector) const {
+        const int new_id = NextD3ID();
+
+        EM_ASM({
+          const id = $0;
+          const selector = UTF8ToString($1);
+          const new_id = $2;
+  	      var new_selection = emp_d3.objects[id].selectAll(selector);
+          emp_d3.objects[new_id] = new_selection;
+        }, this->id, selector.c_str(), new_id);
+
+        return DERIVED(new_id);
+      }
+
+      // TODO - Consider re-implementing the 'Call' wrapper but allow for arbitrary arguments to the
+      //        function being called.
+
+      /// Returns a new selection/transition, representing the current selection/transition
+      /// filtered by [selector]. [selector] can be a C++ function that returns a bool, a
+      /// string representing a function in either the d3, emp, or window namespaces that
+      /// returns a bool, or a string containing a selector to filter by.
+      ///
+      /// For more information see the
+      /// [D3 documentation](https://github.com/d3/d3-3.x-api-reference/blob/master/Selections.md#filter)
+      DERIVED Filter(const std::string & selector) const {
+        const int new_id = NextD3ID();
+
+        EM_ASM({
+          const id = $0;
+          const new_id = $1;
+          const selector_str = UTF8ToString($2);
+          var sel = emp_d3.find_function(selector_str);
+          emp_d3.objects[new_id] = emp_d3.objects[id].filter(sel);
+        }, this->id, new_id, selector.c_str());
+
+        return DERIVED(new_id);
+      }
+
+
+
+  };
+
+}
+
+}
+
+#endif

source/web/d3/test.cc

@@ -8,14 +8,21 @@
 #include "web/init.h"
 #include "web/Document.h"
 #include "d3_init.h"
+#include "selection.h"
 
 // namespace UI = emp::web;
 // UI::Document doc("emp_d3_test");
 
+// EM_JS(const char*, hello, (), {
+//   const js_str = "Hello World!";
+//   return js_str;
+// });
+
 int main() {
 
   D3::internal::get_emp_d3();
   size_t id = D3::internal::NextD3ID();
   std::cout << "This is the ID you got: " << id << std::endl;
+  // std::cout << "This string is from javascript: " << hello() << std::endl;
 
 }