Operator problem with docx

[jgm]

Operator problem with docx

[jgm]

Here's the xml from typing into Word:

<m:oMathPara>
  <m:oMath>
    <m:d>
      <m:dPr>
        <m:ctrlPr>
          <w:rPr>
            <w:rFonts w:ascii="Cambria Math"
            w:hAnsi="Cambria Math" />
            <w:i />
          </w:rPr>
        </m:ctrlPr>
      </m:dPr>
      <m:e>
        <m:nary>
          <m:naryPr>
            <m:chr m:val="∑" />
            <m:limLoc m:val="undOvr" />
            <m:supHide m:val="1" />
            <m:ctrlPr>
              <w:rPr>
                <w:rFonts w:ascii="Cambria Math"
                w:hAnsi="Cambria Math" />
                <w:i />
              </w:rPr>
            </m:ctrlPr>
          </m:naryPr>
          <m:sub>
            <m:r>
              <w:rPr>
                <w:rFonts w:ascii="Cambria Math"
                w:hAnsi="Cambria Math" />
              </w:rPr>
              <m:t>x</m:t>
            </m:r>
          </m:sub>
          <m:sup />
          <m:e>
            <m:r>
              <w:rPr>
                <w:rFonts w:ascii="Cambria Math"
                w:hAnsi="Cambria Math" />
              </w:rPr>
              <m:t>x</m:t>
            </m:r>
          </m:e>
        </m:nary>
      </m:e>
    </m:d>
    <m:d>
      <m:dPr>
        <m:ctrlPr>
          <w:rPr>
            <w:rFonts w:ascii="Cambria Math"
            w:hAnsi="Cambria Math" />
            <w:i />
          </w:rPr>
        </m:ctrlPr>
      </m:dPr>
      <m:e>
        <m:nary>
          <m:naryPr>
            <m:chr m:val="∑" />
            <m:limLoc m:val="undOvr" />
            <m:supHide m:val="1" />
            <m:ctrlPr>
              <w:rPr>
                <w:rFonts w:ascii="Cambria Math"
                w:hAnsi="Cambria Math" />
                <w:i />
              </w:rPr>
            </m:ctrlPr>
          </m:naryPr>
          <m:sub>
            <m:r>
              <w:rPr>
                <w:rFonts w:ascii="Cambria Math"
                w:hAnsi="Cambria Math" />
              </w:rPr>
              <m:t>i</m:t>
            </m:r>
          </m:sub>
          <m:sup />
          <m:e>
            <m:r>
              <w:rPr>
                <w:rFonts w:ascii="Cambria Math"
                w:hAnsi="Cambria Math" />
              </w:rPr>
              <m:t>x</m:t>
            </m:r>
          </m:e>
        </m:nary>
      </m:e>
    </m:d>
  </m:oMath>
</m:oMathPara>

By comparison, here's the xml produced by pandoc:

<m:oMathPara>
  <m:oMathParaPr>
    <m:jc m:val="center" />
  </m:oMathParaPr>
  <m:oMath>
    <m:d>
      <m:dPr>
        <m:begChr m:val="(" />
        <m:endChr m:val=")" />
        <m:grow />
      </m:dPr>
      <m:e>
        <m:limLow>
          <m:e>
            <m:r>
              <m:t>∑</m:t>
            </m:r>
          </m:e>
          <m:lim>
            <m:r>
              <m:t>i</m:t>
            </m:r>
          </m:lim>
        </m:limLow>
        <m:sSub>
          <m:e>
            <m:r>
              <m:t>x</m:t>
            </m:r>
          </m:e>
          <m:sub>
            <m:r>
              <m:t>i</m:t>
            </m:r>
          </m:sub>
        </m:sSub>
      </m:e>
    </m:d>
    <m:nary>
      <m:naryPr>
        <m:chr m:val="∑" />
        <m:limLoc m:val="undOvr" />
        <m:subHide m:val="0" />
        <m:supHide m:val="1" />
      </m:naryPr>
      <m:sub>
        <m:r>
          <m:t>i</m:t>
        </m:r>
      </m:sub>
      <m:sup />
      <m:e>
        <m:sSub>
          <m:e>
            <m:r>
              <m:t>x</m:t>
            </m:r>
          </m:e>
          <m:sub>
            <m:r>
              <m:t>i</m:t>
            </m:r>
          </m:sub>
        </m:sSub>
      </m:e>
    </m:nary>
  </m:oMath>
</m:oMathPara>

[jgm]

I see what's happening. Look at the native output:

[EDelimited "(" ")" [Right (EUnder True (ESymbol Op "\8721") (EIdentifier "i")),Right (ESub (EIdentifier "x") (EIdentifier "i"))],EUnder True (ESymbol Op "\8721") (EIdentifier "i"),ESub (EIdentifier "x") (EIdentifier "i")]

In the OMML writer, we do a preliminary transformation to convert selected EUnder, EUnderOver, etc. into nary:

everywhere (mkT $ handleDownup dt)

where

handleDownUp :: DisplayType -> [Exp] -> [Exp]

This gets the second EUnder but not the first one, since the first one is in an EDelimited context where each non-delimiter element has the Right constructor.

The whole thing is pretty ugly, there must be a better way1