On Mon, 3 Mar 2014, Sanjoy Mahajan wrote:
Aditya Mahajan
writes: This is to announce that the latest beta supports creating virtual math fonts with fallback. The main test case is to use Euler font with missing characters taken from Pagella but the mechanism is general and can be used to replace a specific set of math glyphs from a font.
This feature is not extensively tested. As such it will be useful if everyone interested in math fallback mechanism could test this out and report any bugs or inconsistencies.
One inconsistency or maybe bug is that text subscripts come out in Euler instead of Palatino.
Here's an example (using 2014.02.14 beta). The "Sun" subscript using _{\tf Sun} or _{\rm Sun} was in Palatino in the corresponding MkII setup, but is in Euler now. The workaround of an hbox with \tfxx or \tfx doesn't get quite the right size.
That is because in math mode, \rm is symonym with \mathrm etc. The standard way to write this is _{\text{Sun}}. Aditya