Custom rules for expressions in export to HTML(Fragment)

Question

ExportString[Grid[{{a, b}}], "HTMLFragment"]

"<table><tbody>
     <tr><td>a</td><td>b</td></tr>
 </tbody></table>" 

This is what I expect, but what if I want to convert Grid[{ {c[b, 1], 1} }] and I want an expression with head c to be exported with custom rule, like:

c[x_,y___] :> StringJoin["<div>",ToString[x], "</div>"]

---

So for

ExportString[Grid[{{c[d, 1], b}}], "HTMLFragment"]

I'd get:

"<table><tbody>
     <tr><td> <div>d</div> </td> <td> b </td></tr>
 </tbody></table>"

---

or for:

a[ Grid[{ {c[b, 1], 1} }], 1 ]

"<div>
    <table><tbody>
       <tr>
          <td> <div>b</div> </td> 
          <td> 1 </td>
       </tr>
    </tbody></table>
 </div>"

---

Solution returning XMLElement structure is ok too.

I know I can create a parser and convert everything from top to down but then I have to rewrite rules for things that could've been translated automatically.

Is there simpler approach?

---

Key words: Export HTML HTMLFragment conversion XML XMLElement tag tags

Answer 1

Here's what I've cooked up. Feedback appreciated.

exportWithRules[expr_,rules_]:=Module[{xMLElement,pre,convert},

    convert[s_]:=ExportString[s,"HTMLFragment"];

        (*applying custom rules*)
    pre = ReplaceRepeated[expr,rules];

        (*introducing temporary head to avoid recursion in 
          the evaluation of next XMLElement's conversion*)
    pre = pre /. XMLElement -> xMLElement;

    xMLElement[tag_,opt_, {content___}]:=convert @ XMLElement[ 
        tag, opt, convert /@ {content}
    ];

    convert @ pre
];

exportWithRules[
   c[ Grid[ {{c[b, 1], 1}} ], 1]
   ,
   c[x_, y___] :> XMLElement["div", {}, {x}]
   }
]

 "<div><table><tbody><tr><td><div>b</div></td><td>1</td></tr></tbody></table></div>" 

If one need's indenting:

ExportString[
 ImportString[%, "XML"],
 "XML",
 "ElementFormatting" -> Automatic
 ]

.

 <div>
 <table>
  <tbody>
   <tr>
    <td>
     <div>b</div>
    </td>
    <td>1</td>
   </tr>
  </tbody>
 </table>
</div>