fix(docx): parse integrals as n-ary objects without chr element (#2712)

Signed-off-by: Cesar Berrospi Ramis <ceb@zurich.ibm.com>

docling/backend/docx/latex/latex_dict.py

@@ -65,6 +65,11 @@ CHR_BO = {
     "\u2210": "\\coprod",
     "\u2211": "\\sum",
     "\u222b": "\\int",
+    "\u222c": "\\iint",
+    "\u222d": "\\iiint",
+    "\u222e": "\\oint",
+    "\u222f": "\\oiint",
+    "\u2230": "\\oiiint",
     "\u22c0": "\\bigwedge",
     "\u22c1": "\\bigvee",
     "\u22c2": "\\bigcap",

docling/backend/docx/latex/omml.py

@@ -381,7 +381,8 @@ class oMath2Latex(Tag2Method):
         bo = ""
         for stag, t, e in self.process_children_list(elm):
             if stag == "naryPr":
-                bo = get_val(t.chr, store=CHR_BO)
+                # if <m:naryPr> contains no <m:chr>, the n-ary represents an integral
+                bo = get_val(t.chr, default="\\int", store=CHR_BO)
             else:
                 res.append(t)
         return bo + BLANK.join(res)