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if not modules then modules = { } end modules ['font-oth'] = {
version = 1.001,
comment = "companion to font-oth.lua (helpers)",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
local lpegmatch = lpeg.match
local splitter = lpeg.Ct(lpeg.splitat(" "))
local collect_lookups = fonts.otf.collect_lookups
-- For the moment there is no need to cache this but this might
-- happen when I get the feeling that there is a performance
-- penalty involved.
function fonts.otf.get_alternate(tfmdata,k,kind,value)
if value then
local shared = tfmdata.shared
local otfdata = shared and shared.otfdata
if otfdata then
local validlookups, lookuplist = collect_lookups(otfdata,kind,tfmdata.script,tfmdata.language)
if validlookups then
local lookups = tfmdata.descriptions[k].slookups -- we assume only slookups (we can always extend)
if lookups then
local unicodes = tfmdata.unicodes -- names to unicodes
local choice = tonumber(value)
for l=1,#lookuplist do
local lookup = lookuplist[l]
local p = lookups[lookup]
if p then
local pc = p[2] -- p.components
if pc then
pc = lpegmatch(splitter,pc)
return unicodes[pc[choice] or pc[#pc]]
end
end
end
end
end
end
end
return k
end
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