could textequation put the tag at the start?

[pkra]

Downstream re-arranges tag output from the textequation environment to get left-side tags. This is slightly awkward since tags may or may not be nested in targets.

Could texml do it instead?

The following seems enough to achieve it:

index daf7101..0ec7b1c 100644
--- a/lib/perl/TeX/Interpreter/LaTeX/Package/amsmath.pm
+++ b/lib/perl/TeX/Interpreter/LaTeX/Package/amsmath.pm
@@ -409,9 +409,9 @@ __DATA__
     \startXMLelement{disp-formula}
     \addXMLid
     \setXMLattribute{content-type}{text}
-}{%
     \par
     \process@amsmath@tag
+}{%
     \endXMLelement{disp-formula}
     \par
 }