[luatex] small script to change initial letter forms

[Pablo Rodríguez]

Hi there,

there is a typographical tradition of typesetting Greek using different
glyphs for initial and medial/final forms of beta, theta and phi.

The forms are the following (initial and medial/final):

	βϐ ϑθ ϕφ

OpenType allows this feature to be enabled in the font, but many fonts
which have both glyph forms lack the proper OpenType feature.

I guess the substitution could be performed with a small luatex script
that could be part of Lua(La)TeX or ConTeXt documents.

I would like it to use it with small portions of text and with both the
whole Greek Iliad and Odyssey.

Could anyone explain how can I achieve this?

Many thanks for your help,


Pablo
-- 
http://www.oudeis.tk