ConTeXt can produce tagged PDF - this is really cool! (At the moment ConTeXt/luaTeX seems to be the only macropackage/TeX-engine that is able to do this.)

What is the status of producing structure information for math? After a quick evaluation I observe two issues:

1. Empty entry in RoleMap:

ConTeXt wisely uses the RoleMap entry of the StructTreeRoot element in a PDF to map structure element names to standard element names. In PDF terms, RoleMap is a dictionary with keys and values. Unfortunately, certain math elements seem to lead to a corrupt RoleMap, e.g., the usage of a square root results in an empty dictionary key with corresponding value "\Span". A minimal example is:

2. Structure element contains index of type "real number":

According to the PDF Reference V 1.7 (see Table 10.10) a structure element dictionary's "K" entry can be an integer (e.g. "2") that denotes an index for a marked-content sequence. When tagging math, ConTeXt sometimes produces a real value (e.g. "2.000") instead. A minimal example is: (In this example the last element "B" receives such a "real number" index)

I am using ConTeXt version 2014.05.27 13:38.

Thanks in advance for any feedback.

Christoph