> Alan Bowen <mailto:bowenalan03@gmail.com>
> 2. Oktober 2017 um 14:04
> I need to substitute the regular and italic characters of a 
> publisher’s non-math font (Unicode) for those in a math font.
>
> The non-math addresses are:
> 0041-005A, 0061-007A %italic uppercase and lowercase
> 0391-03A9, 03B1-03C9  %slanted Greek uppercase and lowercase
>
> The math addresses are:
> 1D434-1D44D, 1D44E-1D467 %italic uppercase and lowercase
> 1D6E2-1D6FA, 1D6FC-1D714  %slanted Greek uppercase and lowercase
>
> Is there a way to use the \definefallbackfamily mechanism that does 
> not assume that the characters have the same Unicode addresses? Or is 
> some other approach required?
The fallback mechanism provides a offset key which lets you replace a 
math character with a normal text character.

\definefontfamily     [mainface] [ss] [TeX Gyre Heros]

\definefallbackfamily [mainface] [mm] [TeX Gyre Heros] 
[preset=math:lowercasenormal]
\definefallbackfamily [mainface] [mm] [TeX Gyre Heros] 
[preset=math:lowercaseitalic]
\definefallbackfamily [mainface] [mm] [TeX Gyre Heros] 
[tf=style:italic,range=0x68,offset=0x210E]% lowercase italic h
\definefallbackfamily [mainface] [mm] [TeX Gyre Heros] 
[preset=math:lowercasebold]
\definefallbackfamily [mainface] [mm] [TeX Gyre Heros] 
[preset=math:uppercasenormal]
\definefallbackfamily [mainface] [mm] [TeX Gyre Heros] 
[preset=math:uppercaseitalic]
\definefallbackfamily [mainface] [mm] [TeX Gyre Heros] 
[preset=math:uppercasebold]

\definefontfamily     [mainface] [mm] [TeX Gyre Pagella Math]

\starttext

\setupbodyfont[pagella]

Lowercase: $ {\tf abc} {\it abc} {\bf abc} $

Uppercase: $ {\tf ABC} {\it ABC} {\bf ABC} $

\setupbodyfont[mainface]

Lowercase: $ {\tf abc} {\it abch} {\bf abc} $

Uppercase: $ {\tf ABC} {\it ABC} {\bf ABC} $

\stoptext

Wolfgang