From f6dc9af73c17b0234e1f8a3c30552698894e87df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Wang?= <fwang@igalia.com>
Date: Sat, 13 Apr 2019 10:06:31 -0400
Subject: [PATCH] Avoid extra mstyle attribute when setting
 mathvariant/mathcolor/mathbackground on a single token element. #61

---
 TeXZilla.jison | 31 +++++++++++++++++++++++++------
 unit-tests.js  |  4 ++--
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/TeXZilla.jison b/TeXZilla.jison
index 9c80715..0b2fe61 100644
--- a/TeXZilla.jison
+++ b/TeXZilla.jison
@@ -99,17 +99,36 @@ function newSpace(aWidth) {
    return newTag("mspace", null, {"width": aWidth + "em"});
 }
 
+function isToken(aTree) {
+  return ["mi", "mn", "mo", "mtext", "ms"].indexOf(aTree.tag) !== -1;
+}
+
+function areTokenAttributes(aAttributes) {
+  for (var attribute in aAttributes) {
+    if (["mathcolor", "mathbackground", "mathvariant"].indexOf(attribute) === -1)
+      return false;
+  }
+  return true;
+}
+
 /* FIXME: try to restore the operator grouping when compoundTermList does not
    contain any fences.
    https://github.com/fred-wang/TeXZilla/issues/9 */
 function newMrow(aList, aTag, aAttributes) {
-  var tag;
-  if (!aTag) {
-    if (aList.length == 1) {
-      /* This list only has one element so we just return it. */
-      return aList[0];
+  aTag = aTag || "mrow";
+  if (aList.length == 1) {
+    var child = aList[0];
+    if (aTag === "mrow")
+      return child;
+    if (aTag === "mstyle" &&
+        isToken(child) && areTokenAttributes(aAttributes)) {
+      child.attributes = {};
+      for (var name in aAttributes) {
+        if (!child.attributes[name])
+          child.attributes[name] = aAttributes[name];
+      }
+      return child;
     }
-    aTag = "mrow";
   }
   return newTag(aTag, aList, aAttributes);
 }
diff --git a/unit-tests.js b/unit-tests.js
index 129c2dd..1588db5 100644
--- a/unit-tests.js
+++ b/unit-tests.js
@@ -161,7 +161,7 @@ var tests = [
     ["\\mathraisebox{2}x, \\mathraisebox{-2}x", '<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mpadded voffset="200%" height="+200%"><mi>x</mi></mpadded><mo>,</mo><mpadded voffset="-200%" height="0pt" depth="+200%"><mi>x</mi></mpadded></mrow><annotation encoding="TeX">\\mathraisebox{2}x, \\mathraisebox{-2}x</annotation></semantics></math>'],
     ["\\mathraisebox{negativeveryverythinmathspace}x \\mathraisebox{negativeverythinmathspace}x \\mathraisebox{negativemediummathspace}x \\mathraisebox{negativethickmathspace}x \\mathraisebox{negativeverythickmathspace}x \\mathraisebox{negativeveryverythickmathspace}x \\mathraisebox{veryverythinmathspace}x \\mathraisebox{verythinmathspace}x \\mathraisebox{thinmathspace}x \\mathraisebox{mediummathspace}x \\mathraisebox{thickmathspace}x \\mathraisebox{verythickmathspace}x \\mathraisebox{veryverythickmathspac}x", '<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mpadded voffset="-0.3333333333333333em" height="0pt" depth="+0.3333333333333333em"><mi>x</mi></mpadded><mpadded voffset="-0.2777777777777778em" height="0pt" depth="+0.2777777777777778em"><mi>x</mi></mpadded><mpadded voffset="-0.2222222222222222em" height="0pt" depth="+0.2222222222222222em"><mi>x</mi></mpadded><mpadded voffset="-0.16666666666666666em" height="0pt" depth="+0.16666666666666666em"><mi>x</mi></mpadded><mpadded voffset="-0.1111111111111111em" height="0pt" depth="+0.1111111111111111em"><mi>x</mi></mpadded><mpadded voffset="-0.05555555555555555em" height="0pt" depth="+0.05555555555555555em"><mi>x</mi></mpadded><mpadded voffset="0.05555555555555555em" height="+0.05555555555555555em"><mi>x</mi></mpadded><mpadded voffset="0.1111111111111111em" height="+0.1111111111111111em"><mi>x</mi></mpadded><mpadded voffset="0.16666666666666666em" height="+0.16666666666666666em"><mi>x</mi></mpadded><mpadded voffset="0.2222222222222222em" height="+0.2222222222222222em"><mi>x</mi></mpadded><mpadded voffset="0.2777777777777778em" height="+0.2777777777777778em"><mi>x</mi></mpadded><mpadded voffset="0.3333333333333333em" height="+0.3333333333333333em"><mi>x</mi></mpadded><mpadded voffset="0em" height="+0em"><mi>x</mi></mpadded></mrow><annotation encoding="TeX">\\mathraisebox{negativeveryverythinmathspace}x \\mathraisebox{negativeverythinmathspace}x \\mathraisebox{negativemediummathspace}x \\mathraisebox{negativethickmathspace}x \\mathraisebox{negativeverythickmathspace}x \\mathraisebox{negativeveryverythickmathspace}x \\mathraisebox{veryverythinmathspace}x \\mathraisebox{verythinmathspace}x \\mathraisebox{thinmathspace}x \\mathraisebox{mediummathspace}x \\mathraisebox{thickmathspace}x \\mathraisebox{verythickmathspace}x \\mathraisebox{veryverythickmathspac}x</annotation></semantics></math>'],
     /* mathvariant */
-    ["\\mathbb{x} \\mathbf{x} \\mathit{x} \\mathscr{x} \\mathcal{x}  \\mathscr{x} \\mathbscr{x} \\mathsf{x} \\mathfrak{x} \\mathit{x} \\mathtt{x} \\mathrm{x}", '<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mstyle mathvariant="double-struck"><mi>x</mi></mstyle><mstyle mathvariant="bold"><mi>x</mi></mstyle><mstyle mathvariant="italic"><mi>x</mi></mstyle><mstyle mathvariant="script"><mi>x</mi></mstyle><mstyle mathvariant="script"><mi>x</mi></mstyle><mstyle mathvariant="script"><mi>x</mi></mstyle><mstyle mathvariant="bold-script"><mi>x</mi></mstyle><mstyle mathvariant="sans-serif"><mi>x</mi></mstyle><mstyle mathvariant="fraktur"><mi>x</mi></mstyle><mstyle mathvariant="italic"><mi>x</mi></mstyle><mstyle mathvariant="monospace"><mi>x</mi></mstyle><mstyle mathvariant="normal"><mi>x</mi></mstyle></mrow><annotation encoding="TeX">\\mathbb{x} \\mathbf{x} \\mathit{x} \\mathscr{x} \\mathcal{x}  \\mathscr{x} \\mathbscr{x} \\mathsf{x} \\mathfrak{x} \\mathit{x} \\mathtt{x} \\mathrm{x}</annotation></semantics></math>'],
+    ["\\mathbb{x} \\mathbf{x} \\mathit{x} \\mathscr{x} \\mathcal{x}  \\mathscr{x} \\mathbscr{x} \\mathsf{x} \\mathfrak{x} \\mathit{x} \\mathtt{x} \\mathrm{x}", '<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi mathvariant="double-struck">x</mi><mi mathvariant="bold">x</mi><mi mathvariant="italic">x</mi><mi mathvariant="script">x</mi><mi mathvariant="script">x</mi><mi mathvariant="script">x</mi><mi mathvariant="bold-script">x</mi><mi mathvariant="sans-serif">x</mi><mi mathvariant="fraktur">x</mi><mi mathvariant="italic">x</mi><mi mathvariant="monospace">x</mi><mi mathvariant="normal">x</mi></mrow><annotation encoding="TeX">\\mathbb{x} \\mathbf{x} \\mathit{x} \\mathscr{x} \\mathcal{x}  \\mathscr{x} \\mathbscr{x} \\mathsf{x} \\mathfrak{x} \\mathit{x} \\mathtt{x} \\mathrm{x}</annotation></semantics></math>'],
     ["\\mathbb{x+y} \\mathbf{x+y} \\mathit{x+y} \\mathscr{x+y} \\mathcal{x+y}  \\mathscr{x+y} \\mathbscr{x+y} \\mathsf{x+y} \\mathfrak{x+y} \\mathit{x+y} \\mathtt{x+y} \\mathrm{x+y}", '<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mstyle mathvariant="double-struck"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="bold"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="italic"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="script"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="script"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="script"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="bold-script"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="sans-serif"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="fraktur"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="italic"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="monospace"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle><mstyle mathvariant="normal"><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mstyle></mrow><annotation encoding="TeX">\\mathbb{x+y} \\mathbf{x+y} \\mathit{x+y} \\mathscr{x+y} \\mathcal{x+y}  \\mathscr{x+y} \\mathbscr{x+y} \\mathsf{x+y} \\mathfrak{x+y} \\mathit{x+y} \\mathtt{x+y} \\mathrm{x+y}</annotation></semantics></math>'],
     /* \href */
     ["\\href{http://www.myurl.org}{\\frac a b}", '<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow href="http://www.myurl.org"><mfrac><mi>a</mi><mi>b</mi></mfrac></mrow><annotation encoding="TeX">\\href{http://www.myurl.org}{\\frac a b}</annotation></semantics></math>'],
@@ -229,7 +229,7 @@ var tests = [
        \begin{svg} ... \end{svg} and \includegraphics are not supported
        "&amp;" can not be used as a colsep */
     /* colors */
-    ["{\\color{aqua} x} {\\color{#ff00ff} y} {\\bgcolor{aqua} x} {\\bgcolor{#ff00ff} y}", '<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mstyle mathcolor="aqua"><mi>x</mi></mstyle><mstyle mathcolor="#ff00ff"><mi>y</mi></mstyle><mstyle mathbackground="aqua"><mi>x</mi></mstyle><mstyle mathbackground="#ff00ff"><mi>y</mi></mstyle></mrow><annotation encoding="TeX">{\\color{aqua} x} {\\color{#ff00ff} y} {\\bgcolor{aqua} x} {\\bgcolor{#ff00ff} y}</annotation></semantics></math>'],
+    ["{\\color{aqua} x} {\\color{#ff00ff} y} {\\bgcolor{aqua} x} {\\bgcolor{#ff00ff} y}", '<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi mathcolor="aqua">x</mi><mi mathcolor="#ff00ff">y</mi><mi mathbackground="aqua">x</mi><mi mathbackground="#ff00ff">y</mi></mrow><annotation encoding="TeX">{\\color{aqua} x} {\\color{#ff00ff} y} {\\bgcolor{aqua} x} {\\bgcolor{#ff00ff} y}</annotation></semantics></math>'],
 
     /**** Various char commands ****/
     /* Greek letters */