Move "ordgroup" and "tag" builders into functions/*. (#1339)

* Move "ordgroup" builders to functions/ordgroup.js.
* Move "tag" MathML builder to functions/tag.js.

src/buildHTML.js

@@ -242,9 +242,6 @@ export const makeNullDelimiter = function(options, classes) {
  * Simpler types come at the beginning, while complicated types come afterwards.
  */
 export const groupTypes = {
-    ordgroup: (group, options) => makeSpan(
-        ["mord"], buildExpression(group.value, options, true), options),
-
     supsub(group, options) {
         // Superscript and subscripts are handled in the TeXbook on page
         // 445-446, rules 18(a-f).

src/buildMathML.js

@@ -79,10 +79,6 @@ export const getVariant = function(group, options) {
  */
 export const groupTypes = {};
 
-groupTypes.ordgroup = function(group, options) {
-    return buildExpressionRow(group.value, options);
-};
-
 groupTypes.supsub = function(group, options) {
     // Is the inner group a relevant horizonal brace?
     let isBrace = false;
@@ -140,21 +136,6 @@ groupTypes.supsub = function(group, options) {
     return node;
 };
 
-groupTypes.tag = function(group, options) {
-    const table = new mathMLTree.MathNode("mtable", [
-        new mathMLTree.MathNode("mlabeledtr", [
-            new mathMLTree.MathNode("mtd", [
-                buildExpressionRow(group.value.tag, options),
-            ]),
-            new mathMLTree.MathNode("mtd", [
-                buildExpressionRow(group.value.body, options),
-            ]),
-        ]),
-    ]);
-    table.setAttribute("side", "right");
-    return table;
-};
-
 /**
  * Takes a list of nodes, builds them, and returns a list of the generated
  * MathML nodes.  Also combine consecutive <mtext> outputs into a single

src/defineFunction.js

@@ -210,7 +210,7 @@ export function defineFunctionBuilders<NODETYPE: NodeType>({
     type, htmlBuilder, mathmlBuilder,
 }: {|
     type: NODETYPE,
-    htmlBuilder: HtmlBuilder<NODETYPE>,
+    htmlBuilder?: HtmlBuilder<NODETYPE>,
     mathmlBuilder: MathMLBuilder<NODETYPE>,
 |}) {
     defineFunction({

src/functions.js

@@ -27,6 +27,7 @@ import "./functions/mclass";
 import "./functions/mod";
 import "./functions/op";
 import "./functions/operatorname";
+import "./functions/ordgroup";
 import "./functions/overline";
 import "./functions/phantom";
 import "./functions/raisebox";
@@ -38,6 +39,7 @@ import "./functions/styling";
 import "./functions/symbolsOp";
 import "./functions/symbolsOrd";
 import "./functions/symbolsSpacing";
+import "./functions/tag";
 import "./functions/text";
 import "./functions/underline";
 import "./functions/verb";

src/functions/ordgroup.js

@@ -0,0 +1,18 @@
+// @flow
+import {defineFunctionBuilders} from "../defineFunction";
+import buildCommon from "../buildCommon";
+
+import * as html from "../buildHTML";
+import * as mml from "../buildMathML";
+
+defineFunctionBuilders({
+    type: "ordgroup",
+    htmlBuilder(group, options) {
+        return buildCommon.makeSpan(
+            ["mord"], html.buildExpression(group.value, options, true), options);
+    },
+    mathmlBuilder(group, options) {
+        return mml.buildExpressionRow(group.value, options);
+    },
+});
+

src/functions/tag.js

@@ -0,0 +1,24 @@
+// @flow
+import {defineFunctionBuilders} from "../defineFunction";
+import mathMLTree from "../mathMLTree";
+
+import * as mml from "../buildMathML";
+
+defineFunctionBuilders({
+    type: "tag",
+    mathmlBuilder(group, options) {
+        const table = new mathMLTree.MathNode("mtable", [
+            new mathMLTree.MathNode("mlabeledtr", [
+                new mathMLTree.MathNode("mtd", [
+                    mml.buildExpressionRow(group.value.tag, options),
+                ]),
+                new mathMLTree.MathNode("mtd", [
+                    mml.buildExpressionRow(group.value.body, options),
+                ]),
+            ]),
+        ]);
+        table.setAttribute("side", "right");
+        return table;
+    },
+});
+

src/mathMLTree.js

@@ -20,7 +20,7 @@ export type MathNodeType =
     "mtext" | "mn" | "mo" | "mi" | "mspace" |
     "mover" | "munder" | "munderover" | "msup" | "msub" |
     "mfrac" | "mroot" | "msqrt" |
-    "mtable" | "mtr" | "mtd" |
+    "mtable" | "mtr" | "mtd" | "mlabeledtr" |
     "mrow" | "menclose" |
     "mstyle" | "mpadded" | "mphantom";