diff --git a/src/functions/genfrac.js b/src/functions/genfrac.js
index 3ce6d66d..e757bea7 100644
--- a/src/functions/genfrac.js
+++ b/src/functions/genfrac.js
@@ -9,6 +9,202 @@ import ParseNode from "../ParseNode";
 import * as html from "../buildHTML";
 import * as mml from "../buildMathML";
 
+const htmlBuilder = (group, options) => {
+    // Fractions are handled in the TeXbook on pages 444-445, rules 15(a-e).
+    // Figure out what style this fraction should be in based on the
+    // function used
+    let style = options.style;
+    if (group.value.size === "display") {
+        style = Style.DISPLAY;
+    } else if (group.value.size === "text" &&
+        style.size === Style.DISPLAY.size) {
+        // We're in a \tfrac but incoming style is displaystyle, so:
+        style = Style.TEXT;
+    }
+
+    const nstyle = style.fracNum();
+    const dstyle = style.fracDen();
+    let newOptions;
+
+    newOptions = options.havingStyle(nstyle);
+    const numerm = html.buildGroup(group.value.numer, newOptions, options);
+
+    if (group.value.continued) {
+        // \cfrac inserts a \strut into the numerator.
+        // Get \strut dimensions from TeXbook page 353.
+        const hStrut = 8.5 / options.fontMetrics().ptPerEm;
+        const dStrut = 3.5 / options.fontMetrics().ptPerEm;
+        numerm.height = numerm.height < hStrut ? hStrut : numerm.height;
+        numerm.depth = numerm.depth < dStrut ? dStrut : numerm.depth;
+    }
+
+    newOptions = options.havingStyle(dstyle);
+    const denomm = html.buildGroup(group.value.denom, newOptions, options);
+
+    let rule;
+    let ruleWidth;
+    let ruleSpacing;
+    if (group.value.hasBarLine) {
+        rule = buildCommon.makeLineSpan("frac-line", options);
+        ruleWidth = rule.height;
+        ruleSpacing = rule.height;
+    } else {
+        rule = null;
+        ruleWidth = 0;
+        ruleSpacing = options.fontMetrics().defaultRuleThickness;
+    }
+
+    // Rule 15b
+    let numShift;
+    let clearance;
+    let denomShift;
+    if (style.size === Style.DISPLAY.size) {
+        numShift = options.fontMetrics().num1;
+        if (ruleWidth > 0) {
+            clearance = 3 * ruleSpacing;
+        } else {
+            clearance = 7 * ruleSpacing;
+        }
+        denomShift = options.fontMetrics().denom1;
+    } else {
+        if (ruleWidth > 0) {
+            numShift = options.fontMetrics().num2;
+            clearance = ruleSpacing;
+        } else {
+            numShift = options.fontMetrics().num3;
+            clearance = 3 * ruleSpacing;
+        }
+        denomShift = options.fontMetrics().denom2;
+    }
+
+    let frac;
+    if (!rule) {
+        // Rule 15c
+        const candidateClearance =
+            (numShift - numerm.depth) - (denomm.height - denomShift);
+        if (candidateClearance < clearance) {
+            numShift += 0.5 * (clearance - candidateClearance);
+            denomShift += 0.5 * (clearance - candidateClearance);
+        }
+
+        frac = buildCommon.makeVList({
+            positionType: "individualShift",
+            children: [
+                {type: "elem", elem: denomm, shift: denomShift},
+                {type: "elem", elem: numerm, shift: -numShift},
+            ],
+        }, options);
+    } else {
+        // Rule 15d
+        const axisHeight = options.fontMetrics().axisHeight;
+
+        if ((numShift - numerm.depth) - (axisHeight + 0.5 * ruleWidth) <
+                clearance) {
+            numShift +=
+                clearance - ((numShift - numerm.depth) -
+                            (axisHeight + 0.5 * ruleWidth));
+        }
+
+        if ((axisHeight - 0.5 * ruleWidth) - (denomm.height - denomShift) <
+                clearance) {
+            denomShift +=
+                clearance - ((axisHeight - 0.5 * ruleWidth) -
+                            (denomm.height - denomShift));
+        }
+
+        const midShift = -(axisHeight - 0.5 * ruleWidth);
+
+        frac = buildCommon.makeVList({
+            positionType: "individualShift",
+            children: [
+                {type: "elem", elem: denomm, shift: denomShift},
+                {type: "elem", elem: rule,   shift: midShift},
+                {type: "elem", elem: numerm, shift: -numShift},
+            ],
+        }, options);
+    }
+
+    // Since we manually change the style sometimes (with \dfrac or \tfrac),
+    // account for the possible size change here.
+    newOptions = options.havingStyle(style);
+    frac.height *= newOptions.sizeMultiplier / options.sizeMultiplier;
+    frac.depth *= newOptions.sizeMultiplier / options.sizeMultiplier;
+
+    // Rule 15e
+    let delimSize;
+    if (style.size === Style.DISPLAY.size) {
+        delimSize = options.fontMetrics().delim1;
+    } else {
+        delimSize = options.fontMetrics().delim2;
+    }
+
+    let leftDelim;
+    let rightDelim;
+    if (group.value.leftDelim == null) {
+        leftDelim = html.makeNullDelimiter(options, ["mopen"]);
+    } else {
+        leftDelim = delimiter.customSizedDelim(
+            group.value.leftDelim, delimSize, true,
+            options.havingStyle(style), group.mode, ["mopen"]);
+    }
+
+    if (group.value.continued) {
+        rightDelim = buildCommon.makeSpan([]); // zero width for \cfrac
+    } else if (group.value.rightDelim == null) {
+        rightDelim = html.makeNullDelimiter(options, ["mclose"]);
+    } else {
+        rightDelim = delimiter.customSizedDelim(
+            group.value.rightDelim, delimSize, true,
+            options.havingStyle(style), group.mode, ["mclose"]);
+    }
+
+    return buildCommon.makeSpan(
+        ["mord"].concat(newOptions.sizingClasses(options)),
+        [leftDelim, buildCommon.makeSpan(["mfrac"], [frac]), rightDelim],
+        options);
+};
+
+const mathmlBuilder = (group, options) => {
+    const node = new mathMLTree.MathNode(
+        "mfrac",
+        [
+            mml.buildGroup(group.value.numer, options),
+            mml.buildGroup(group.value.denom, options),
+        ]);
+
+    if (!group.value.hasBarLine) {
+        node.setAttribute("linethickness", "0px");
+    }
+
+    if (group.value.leftDelim != null || group.value.rightDelim != null) {
+        const withDelims = [];
+
+        if (group.value.leftDelim != null) {
+            const leftOp = new mathMLTree.MathNode(
+                "mo", [new mathMLTree.TextNode(group.value.leftDelim)]);
+
+            leftOp.setAttribute("fence", "true");
+
+            withDelims.push(leftOp);
+        }
+
+        withDelims.push(node);
+
+        if (group.value.rightDelim != null) {
+            const rightOp = new mathMLTree.MathNode(
+                "mo", [new mathMLTree.TextNode(group.value.rightDelim)]);
+
+            rightOp.setAttribute("fence", "true");
+
+            withDelims.push(rightOp);
+        }
+
+        return mml.makeRow(withDelims);
+    }
+
+    return node;
+};
+
 defineFunction({
     type: "genfrac",
     names: [
@@ -83,200 +279,9 @@ defineFunction({
             size: size,
         }, parser.mode);
     },
-    htmlBuilder: (group, options) => {
-        // Fractions are handled in the TeXbook on pages 444-445, rules 15(a-e).
-        // Figure out what style this fraction should be in based on the
-        // function used
-        let style = options.style;
-        if (group.value.size === "display") {
-            style = Style.DISPLAY;
-        } else if (group.value.size === "text" &&
-            style.size === Style.DISPLAY.size) {
-            // We're in a \tfrac but incoming style is displaystyle, so:
-            style = Style.TEXT;
-        }
 
-        const nstyle = style.fracNum();
-        const dstyle = style.fracDen();
-        let newOptions;
-
-        newOptions = options.havingStyle(nstyle);
-        const numerm = html.buildGroup(group.value.numer, newOptions, options);
-
-        if (group.value.continued) {
-            // \cfrac inserts a \strut into the numerator.
-            // Get \strut dimensions from TeXbook page 353.
-            const hStrut = 8.5 / options.fontMetrics().ptPerEm;
-            const dStrut = 3.5 / options.fontMetrics().ptPerEm;
-            numerm.height = numerm.height < hStrut ? hStrut : numerm.height;
-            numerm.depth = numerm.depth < dStrut ? dStrut : numerm.depth;
-        }
-
-        newOptions = options.havingStyle(dstyle);
-        const denomm = html.buildGroup(group.value.denom, newOptions, options);
-
-        let rule;
-        let ruleWidth;
-        let ruleSpacing;
-        if (group.value.hasBarLine) {
-            rule = buildCommon.makeLineSpan("frac-line", options);
-            ruleWidth = rule.height;
-            ruleSpacing = rule.height;
-        } else {
-            rule = null;
-            ruleWidth = 0;
-            ruleSpacing = options.fontMetrics().defaultRuleThickness;
-        }
-
-        // Rule 15b
-        let numShift;
-        let clearance;
-        let denomShift;
-        if (style.size === Style.DISPLAY.size) {
-            numShift = options.fontMetrics().num1;
-            if (ruleWidth > 0) {
-                clearance = 3 * ruleSpacing;
-            } else {
-                clearance = 7 * ruleSpacing;
-            }
-            denomShift = options.fontMetrics().denom1;
-        } else {
-            if (ruleWidth > 0) {
-                numShift = options.fontMetrics().num2;
-                clearance = ruleSpacing;
-            } else {
-                numShift = options.fontMetrics().num3;
-                clearance = 3 * ruleSpacing;
-            }
-            denomShift = options.fontMetrics().denom2;
-        }
-
-        let frac;
-        if (!rule) {
-            // Rule 15c
-            const candidateClearance =
-                (numShift - numerm.depth) - (denomm.height - denomShift);
-            if (candidateClearance < clearance) {
-                numShift += 0.5 * (clearance - candidateClearance);
-                denomShift += 0.5 * (clearance - candidateClearance);
-            }
-
-            frac = buildCommon.makeVList({
-                positionType: "individualShift",
-                children: [
-                    {type: "elem", elem: denomm, shift: denomShift},
-                    {type: "elem", elem: numerm, shift: -numShift},
-                ],
-            }, options);
-        } else {
-            // Rule 15d
-            const axisHeight = options.fontMetrics().axisHeight;
-
-            if ((numShift - numerm.depth) - (axisHeight + 0.5 * ruleWidth) <
-                    clearance) {
-                numShift +=
-                    clearance - ((numShift - numerm.depth) -
-                                (axisHeight + 0.5 * ruleWidth));
-            }
-
-            if ((axisHeight - 0.5 * ruleWidth) - (denomm.height - denomShift) <
-                    clearance) {
-                denomShift +=
-                    clearance - ((axisHeight - 0.5 * ruleWidth) -
-                                (denomm.height - denomShift));
-            }
-
-            const midShift = -(axisHeight - 0.5 * ruleWidth);
-
-            frac = buildCommon.makeVList({
-                positionType: "individualShift",
-                children: [
-                    {type: "elem", elem: denomm, shift: denomShift},
-                    {type: "elem", elem: rule,   shift: midShift},
-                    {type: "elem", elem: numerm, shift: -numShift},
-                ],
-            }, options);
-        }
-
-        // Since we manually change the style sometimes (with \dfrac or \tfrac),
-        // account for the possible size change here.
-        newOptions = options.havingStyle(style);
-        frac.height *= newOptions.sizeMultiplier / options.sizeMultiplier;
-        frac.depth *= newOptions.sizeMultiplier / options.sizeMultiplier;
-
-        // Rule 15e
-        let delimSize;
-        if (style.size === Style.DISPLAY.size) {
-            delimSize = options.fontMetrics().delim1;
-        } else {
-            delimSize = options.fontMetrics().delim2;
-        }
-
-        let leftDelim;
-        let rightDelim;
-        if (group.value.leftDelim == null) {
-            leftDelim = html.makeNullDelimiter(options, ["mopen"]);
-        } else {
-            leftDelim = delimiter.customSizedDelim(
-                group.value.leftDelim, delimSize, true,
-                options.havingStyle(style), group.mode, ["mopen"]);
-        }
-
-        if (group.value.continued) {
-            rightDelim = buildCommon.makeSpan([]); // zero width for \cfrac
-        } else if (group.value.rightDelim == null) {
-            rightDelim = html.makeNullDelimiter(options, ["mclose"]);
-        } else {
-            rightDelim = delimiter.customSizedDelim(
-                group.value.rightDelim, delimSize, true,
-                options.havingStyle(style), group.mode, ["mclose"]);
-        }
-
-        return buildCommon.makeSpan(
-            ["mord"].concat(newOptions.sizingClasses(options)),
-            [leftDelim, buildCommon.makeSpan(["mfrac"], [frac]), rightDelim],
-            options);
-    },
-    mathmlBuilder: (group, options) => {
-        const node = new mathMLTree.MathNode(
-            "mfrac",
-            [
-                mml.buildGroup(group.value.numer, options),
-                mml.buildGroup(group.value.denom, options),
-            ]);
-
-        if (!group.value.hasBarLine) {
-            node.setAttribute("linethickness", "0px");
-        }
-
-        if (group.value.leftDelim != null || group.value.rightDelim != null) {
-            const withDelims = [];
-
-            if (group.value.leftDelim != null) {
-                const leftOp = new mathMLTree.MathNode(
-                    "mo", [new mathMLTree.TextNode(group.value.leftDelim)]);
-
-                leftOp.setAttribute("fence", "true");
-
-                withDelims.push(leftOp);
-            }
-
-            withDelims.push(node);
-
-            if (group.value.rightDelim != null) {
-                const rightOp = new mathMLTree.MathNode(
-                    "mo", [new mathMLTree.TextNode(group.value.rightDelim)]);
-
-                rightOp.setAttribute("fence", "true");
-
-                withDelims.push(rightOp);
-            }
-
-            return mml.makeRow(withDelims);
-        }
-
-        return node;
-    },
+    htmlBuilder,
+    mathmlBuilder,
 });
 
 // Infix generalized fractions -- these are not rendered directly, but replaced
@@ -316,4 +321,3 @@ defineFunction({
         }, parser.mode);
     },
 });
-