Generic getter-setter property.

d3.js

@@ -7887,34 +7887,22 @@
     return identity;
   }
   d3.svg = {};
+  function d3_property_number(object, name, value) {
+    object[name] = function(_) {
+      return arguments.length ? (value = typeof _ === "function" ? _ : +_, object) : value;
+    };
+    return function(that, args) {
+      return typeof value === "function" ? +value.apply(that, args) : value;
+    };
+  }
   d3.svg.arc = function() {
-    var innerRadius = d3_svg_arcInnerRadius, outerRadius = d3_svg_arcOuterRadius, startAngle = d3_svg_arcStartAngle, endAngle = d3_svg_arcEndAngle;
+    var innerRadius = d3_property_number(arc, "innerRadius", d3_svg_arcInnerRadius), outerRadius = d3_property_number(arc, "outerRadius", d3_svg_arcOuterRadius), startAngle = d3_property_number(arc, "startAngle", d3_svg_arcStartAngle), endAngle = d3_property_number(arc, "endAngle", d3_svg_arcEndAngle);
     function arc() {
-      var r0 = innerRadius.apply(this, arguments), r1 = outerRadius.apply(this, arguments), a0 = startAngle.apply(this, arguments) + d3_svg_arcOffset, a1 = endAngle.apply(this, arguments) + d3_svg_arcOffset, da = Math.abs(a1 - a0), df = da < π ? " 0 0" : " 0 1", fs = a1 < a0 ? ",0 " : ",1 ", ss = a1 < a0 ? ",1 " : ",0 ", c0 = Math.cos(a0), s0 = Math.sin(a0), c1 = Math.cos(a1), s1 = Math.sin(a1);
+      var r0 = innerRadius(this, arguments), r1 = outerRadius(this, arguments), a0 = startAngle(this, arguments) + d3_svg_arcOffset, a1 = endAngle(this, arguments) + d3_svg_arcOffset, da = Math.abs(a1 - a0), df = da < π ? " 0 0" : " 0 1", fs = a1 < a0 ? ",0 " : ",1 ", ss = a1 < a0 ? ",1 " : ",0 ", c0 = Math.cos(a0), s0 = Math.sin(a0), c1 = Math.cos(a1), s1 = Math.sin(a1);
       return da >= d3_svg_arcMax ? r0 ? "M0," + r1 + "A" + r1 + "," + r1 + " 0 1" + fs + "0," + -r1 + "A" + r1 + "," + r1 + " 0 1" + fs + "0," + r1 + "M0," + r0 + "A" + r0 + "," + r0 + " 0 1" + ss + "0," + -r0 + "A" + r0 + "," + r0 + " 0 1" + ss + "0," + r0 + "Z" : "M0," + r1 + "A" + r1 + "," + r1 + " 0 1" + fs + "0," + -r1 + "A" + r1 + "," + r1 + " 0 1" + fs + "0," + r1 + "Z" : r0 ? "M" + r1 * c0 + "," + r1 * s0 + "A" + r1 + "," + r1 + df + fs + r1 * c1 + "," + r1 * s1 + "L" + r0 * c1 + "," + r0 * s1 + "A" + r0 + "," + r0 + df + ss + r0 * c0 + "," + r0 * s0 + "Z" : "M" + r1 * c0 + "," + r1 * s0 + "A" + r1 + "," + r1 + df + fs + r1 * c1 + "," + r1 * s1 + "L0,0Z";
     }
-    arc.innerRadius = function(v) {
-      if (!arguments.length) return innerRadius;
-      innerRadius = d3_functor(v);
-      return arc;
-    };
-    arc.outerRadius = function(v) {
-      if (!arguments.length) return outerRadius;
-      outerRadius = d3_functor(v);
-      return arc;
-    };
-    arc.startAngle = function(v) {
-      if (!arguments.length) return startAngle;
-      startAngle = d3_functor(v);
-      return arc;
-    };
-    arc.endAngle = function(v) {
-      if (!arguments.length) return endAngle;
-      endAngle = d3_functor(v);
-      return arc;
-    };
     arc.centroid = function() {
-      var r = (innerRadius.apply(this, arguments) + outerRadius.apply(this, arguments)) / 2, a = (startAngle.apply(this, arguments) + endAngle.apply(this, arguments)) / 2 + d3_svg_arcOffset;
+      var r = (innerRadius(this, arguments) + outerRadius(this, arguments)) / 2, a = (startAngle(this, arguments) + endAngle(this, arguments)) / 2 + d3_svg_arcOffset;
       return [ Math.cos(a) * r, Math.sin(a) * r ];
     };
     return arc;

src/core/property.js

@@ -0,0 +1,10 @@
+function d3_property_number(object, name, value) {
+
+  object[name] = function(_) {
+    return arguments.length ? (value = typeof _ === "function" ? _ : +_, object) : value;
+  };
+
+  return function(that, args) {
+    return typeof value === "function" ? +value.apply(that, args) : value;
+  };
+}

src/svg/arc.js

@@ -1,18 +1,18 @@
-import "../core/functor";
+import "../core/property";
 import "../math/trigonometry";
 import "svg";
 
 d3.svg.arc = function() {
-  var innerRadius = d3_svg_arcInnerRadius,
-      outerRadius = d3_svg_arcOuterRadius,
-      startAngle = d3_svg_arcStartAngle,
-      endAngle = d3_svg_arcEndAngle;
+  var innerRadius = d3_property_number(arc, "innerRadius", d3_svg_arcInnerRadius),
+      outerRadius = d3_property_number(arc, "outerRadius", d3_svg_arcOuterRadius),
+      startAngle = d3_property_number(arc, "startAngle", d3_svg_arcStartAngle),
+      endAngle = d3_property_number(arc, "endAngle", d3_svg_arcEndAngle);
 
   function arc() {
-    var r0 = innerRadius.apply(this, arguments),
-        r1 = outerRadius.apply(this, arguments),
-        a0 = startAngle.apply(this, arguments) + d3_svg_arcOffset,
-        a1 = endAngle.apply(this, arguments) + d3_svg_arcOffset,
+    var r0 = innerRadius(this, arguments),
+        r1 = outerRadius(this, arguments),
+        a0 = startAngle(this, arguments) + d3_svg_arcOffset,
+        a1 = endAngle(this, arguments) + d3_svg_arcOffset,
         da = Math.abs(a1 - a0),
         df = da < π ? " 0 0" : " 0 1",
         fs = a1 < a0 ? ",0 " : ",1 ",
@@ -45,35 +45,9 @@ d3.svg.arc = function() {
       + "L0,0Z");
   }
 
-  arc.innerRadius = function(v) {
-    if (!arguments.length) return innerRadius;
-    innerRadius = d3_functor(v);
-    return arc;
-  };
-
-  arc.outerRadius = function(v) {
-    if (!arguments.length) return outerRadius;
-    outerRadius = d3_functor(v);
-    return arc;
-  };
-
-  arc.startAngle = function(v) {
-    if (!arguments.length) return startAngle;
-    startAngle = d3_functor(v);
-    return arc;
-  };
-
-  arc.endAngle = function(v) {
-    if (!arguments.length) return endAngle;
-    endAngle = d3_functor(v);
-    return arc;
-  };
-
   arc.centroid = function() {
-    var r = (innerRadius.apply(this, arguments)
-        + outerRadius.apply(this, arguments)) / 2,
-        a = (startAngle.apply(this, arguments)
-        + endAngle.apply(this, arguments)) / 2 + d3_svg_arcOffset;
+    var r = (innerRadius(this, arguments) + outerRadius(this, arguments)) / 2,
+        a = (startAngle(this, arguments) + endAngle(this, arguments)) / 2 + d3_svg_arcOffset;
     return [Math.cos(a) * r, Math.sin(a) * r];
   };