In LaTeX, it is possible to produce the greek expression Ἑλληνικὴ γλώσσα with command
\textgreek{<Ellhnik`h gl'wssa}
i.e., using only latin characters and without having to use any greek letters in the TeX-file.
This particular command DOES NOT work in XeLaTeX.
Is there a way to turn latin characters into greek characters in XeLaTeX?
I am not talking about having to write something like
$\gamma\lambda\'\omega\sigma\sigma\alpha$.
Since this problem is related to XeTeX, I assume that your document can be migrated to LuaTeX without too much trouble. First of all, I have to say that I know nothing about Greek, but at least I understand a little bit about what needs to be done based on the files shared by Davislor in the comments. The solution I come up with is shown below.
\textgreek only supports text, which means almost no LaTeX commands will work correctly inside.L2G_VARIANT_GRAVE, L2G_VARIANT_ROUGH and L2G_VARIANT_ACUTE. You have to fill in new mappings inside _l2g_variant_indicator table.\documentclass{exam}
\usepackage{fontspec}
\usepackage{luacode}
\usepackage{expl3}
\setmainfont{DejaVu Serif}
\begin{luacode*}
L2G_VARIANT_ACUTE = 0x00000001
L2G_VARIANT_CIRCUM = 0x00000002
L2G_VARIANT_DIA = 0x00000004
L2G_VARIANT_DIACIRCUM = 0x00000008
L2G_VARIANT_DIAGRAVE = 0x00000010
L2G_VARIANT_GRAVE = 0x00000020
L2G_VARIANT_IOTASUB = 0x00000040
L2G_VARIANT_ROUGH = 0x00000080
L2G_VARIANT_SMOOTH = 0x00000100
l2g_variants = {
"acute", "circum", "dia", "diacircum", "diagrave", "grave", "iotasub", "rough", "smooth"
}
l2g_char_mapping = {
[97]=945,[98]=946,[99]=958,[100]=948,[101]=949,[102]=966,
[103]=947,[104]=951,[105]=953,[107]=954,[108]=955,[109]=956,
[110]=957,[111]=959,[112]=960,[113]=952,[114]=961,[116]=964,
[117]=965,[118]=989,[119]=969,[120]=958,[121]=968,[122]=950,
[65]=913,[66]=914,[67]=926,[68]=916,[69]=917,[70]=934,
[71]=915,[72]=919,[73]=921,[75]=922,[76]=923,[77]=924,
[78]=925,[79]=927,[80]=928,[81]=920,[82]=929,[84]=932,
[85]=933,[86]=988,[87]=937,[88]=926,[89]=936,[90]=918
}
_l2g_variant_indicator = {
["`"] = L2G_VARIANT_GRAVE,
["<"] = L2G_VARIANT_ROUGH,
["'"] = L2G_VARIANT_ACUTE
}
-- an integer version of _l2g_variant_indicator will be generated right away
l2g_variant_indicator = {}
for key, val in pairs(_l2g_variant_indicator) do
local ind = key:byte(1)
l2g_variant_indicator[ind] = val
end
l2g_variant_mapping = {
[97]={[256]=7936,[288]=7938,[352]=8066,[128]=7937,[160]=7939,[224]=8067,[257]=7940,[321]=8068,[129]=7941,[193]=8069,[258]=7942,[322]=8070,[130]=7943,[194]=8071,[320]=8064,[192]=8065,[32]=8048,[96]=8114,[1]=940,[65]=8116,[2]=8118,[66]=8119,[64]=8115},
[65]={[256]=7944,[288]=7946,[352]=8074,[128]=7945,[160]=7947,[224]=8075,[257]=7948,[321]=8076,[129]=7949,[193]=8077,[258]=7950,[322]=8078,[130]=7951,[194]=8079,[320]=8072,[192]=8073,[1]=902,[32]=8122,[64]=8124},
[104]={[256]=7968,[288]=7970,[352]=8082,[128]=7969,[160]=7971,[224]=8083,[257]=7972,[321]=8084,[129]=7973,[193]=8085,[258]=7974,[322]=8086,[320]=8080,[192]=8081,[1]=942,[65]=8132,[2]=8134,[66]=8135,[32]=8052,[64]=8131},
[72]={[256]=7976,[288]=7978,[352]=8090,[128]=7977,[160]=7979,[224]=8091,[257]=7980,[321]=8092,[129]=7981,[193]=8093,[258]=7982,[322]=8094,[320]=8088,[192]=8089,[1]=905,[32]=8138,[64]=8140},
[119]={[256]=8032,[288]=8034,[352]=8098,[128]=8097,[160]=8035,[224]=8099,[257]=8036,[321]=8100,[129]=8037,[193]=8101,[258]=8038,[322]=8102,[130]=8039,[194]=8103,[320]=8096,[192]=8097,[32]=8060,[96]=8178,[1]=974,[65]=8180,[2]=8182,[66]=8183,[64]=8179},
[87]={[256]=8040,[288]=8042,[352]=8106,[128]=8041,[160]=8043,[224]=8107,[257]=8044,[321]=8108,[129]=8045,[193]=8109,[258]=8046,[322]=8110,[130]=8047,[194]=8111,[320]=8104,[192]=8105,[1]=911,[32]=8186,[64]=8188},
[105]={[4]=970,[5]=912,[256]=7984,[288]=7986,[128]=7985,[160]=7987,[257]=7988,[129]=7989,[258]=7990,[130]=7991,[36]=8146,[16]=8146,[6]=8151,[8]=8151,[1]=943,[32]=8054,[2]=8150},
[117]={[4]=971,[5]=944,[256]=8016,[288]=8018,[128]=8017,[160]=8019,[257]=8020,[129]=8021,[258]=8022,[130]=8023,[36]=8162,[16]=8162,[6]=8167,[8]=8167,[1]=973,[32]=8058,[2]=8166},
[101]={[256]=7952,[288]=7954,[128]=7953,[160]=7955,[257]=7956,[129]=7957,[1]=941,[32]=8050},
[69]={[256]=7960,[288]=7962,[128]=7961,[160]=7963,[257]=7964,[129]=7965,[1]=904,[32]=8136},
[73]={[256]=7992,[288]=7994,[128]=7993,[160]=7995,[257]=7996,[129]=7997,[258]=7998,[130]=7999,[1]=906,[4]=938,[32]=8154},
[111]={[256]=8000,[288]=8002,[128]=8001,[160]=8003,[257]=8004,[129]=8005,[1]=972,[32]=8056},
[79]={[256]=8008,[288]=8010,[128]=8009,[160]=8011,[257]=8012,[129]=8013,[1]=908,[32]=8184},
[85]={[128]=8017,[160]=8027,[129]=8029,[130]=8031,[1]=910,[4]=939,[32]=8170},
[114]={[256]=8164,[128]=8165},
[82]={[128]=8172}
}
-- assume Lua 5.3 is used, otherwise may need to use bit32 library
-- https://stackoverflow.com/questions/5977654/how-do-i-use-the-bitwise-operator-xor-in-lua
function l2g_bitwise_or(a, b)
return a | b
end
function l2g_print_warning(s)
tex.print(string.format([[\PackageWarning{l2g}{%s}]], s))
end
function l2g_code_to_char(c)
return utf8.char(c)
end
l2gstate = {
["variant_flag"] = 0,
["variant_storage"] = -1,
["result"] = -1
}
function l2gstate:new()
local obj = {}
setmetatable(obj, self)
self.__index = self
self.result = {}
self.variant_storage = {}
return obj
end
function l2gstate:get_last_variant()
local len = #self.variant_storage
if len == 0 then
return -1
end
local last_char = self.variant_storage[len]
return utf8.codepoint(last_char)
end
function l2gstate:register_variant(var_ccode)
local var_flag = l2g_variant_indicator[var_ccode]
self.variant_flag = l2g_bitwise_or(self.variant_flag, var_flag)
table.insert(self.variant_storage, l2g_code_to_char(var_ccode))
end
function l2gstate:discard_variant()
self.variant_flag = 0
self.variant_storage = {}
end
function l2gstate:add_variant_char()
for _, val in ipairs(self.variant_storage) do
table.insert(self.result, val)
end
end
function l2gstate:add_char(code)
table.insert(self.result, l2g_code_to_char(code))
end
function l2g(s)
local pos = 1
local cur_byte = -1
local cur_char = nil
local variant_state = l2gstate:new()
local char_find = nil
local inner_find = nil
local inner_char_find = nil
while pos <= utf8.len(s) do
cur_byte = utf8.codepoint(s, pos)
cur_char = utf8.char(cur_byte)
variant_find = l2g_variant_indicator[cur_byte]
if variant_find ~= nil then
if cur_byte == variant_state:get_last_variant() then
-- escaping current sequence
variant_state:add_char(cur_byte)
variant_state:discard_variant()
else
variant_state:register_variant(cur_byte)
end
goto continue
end
char_find = l2g_char_mapping[cur_byte]
if char_find ~= nil then
-- try to resolve variants
if variant_state.variant_flag > 0 then
inner_find = l2g_variant_mapping[cur_byte]
if inner_find ~= nil then
inner_char_find = inner_find[variant_state.variant_flag]
if inner_char_find ~= nil then
variant_state:add_char(inner_char_find)
else
l2g_print_warning(string.format("letter '%s' does not have variant type %d", cur_char, variant_state.variant_flag))
variant_state:add_variant_char()
variant_state:add_char(cur_byte)
end
else
l2g_print_warning(string.format("letter '%s' does not have any variant", cur_char))
variant_state:add_variant_char()
variant_state:add_char(cur_byte)
end
variant_state:discard_variant()
else
-- no variant set for this character
variant_state:add_char(char_find)
end
else
-- unable to find this character in mapping
variant_state:add_variant_char()
variant_state:add_char(cur_byte)
variant_state:discard_variant()
end
::continue::
pos = pos + 1
end
if variant_state:get_last_variant() ~= -1 then
variant_state:add_variant_char()
variant_state:discard_variant()
end
return table.concat(variant_state.result, "")
end
\end{luacode*}
\newcommand{\textgreek}[1]{
\directlua{
local res = l2g("\luaescapestring{#1}")
tex.print(res)
}
}
\begin{document}
\par \textgreek{<Ellhnik`h gl'wssa}
\par \textgreek{<Ellhnik<`h gl<'wssa}
\par \textgreek{<<Ellhnik``h gl''wssa}
\end{document}
The result is:
Ἑλληνικὴ γλώssα
Ἑλληνικἣ γλὥssα
<Ελληνικ‘η γλ’ωssα
Although you don’t provide a complete MWE, it appears that you’re using the teubner package, directly or indirectly through babel. This is different from beta code or a direct mapping to LGR.
My first suggestion would be, if feasible, to convert the input to Unicode, which you can search, copy, paste, spell-check, edit with whatever input method you normally use for Greek, etc. This is especially the case if it’s polytonic Greek, where the mapping of the unaccented Greek alphabet to its Latin transliteration breaks down.
How difficult it would be to parse your LaTeX source with an external script and generate a new source file in UTF-8 depends on how complex the \textgreek expressions are. If they’re all like your example, it could be done with regular expressions. If they can contain only well-behaved, non-nested commands such as \textbf{<Ellhnik`h}, it’s still possible to do mechanically without writing a more complex parser. If your input can contain arbitrarily-nested commands, you would need to write at least a parser that can match braces, and if commands can do complex things like change the language, you would need to scan for that. If you pass programmatically-generated strings to \textgreek, you’d need to rewrite that by hand.
Be aware that XeTeX and LuaTeX only support precomposed (NFC) Greek characters as of 2020, not combining Greek accents. I’m told by the package maintainers that the babel language files are likely to get a fix for this before the Unicode hyphenation algorithm does.
It would be possible to write a .tec mapping file that converts Teubner codes to Unicode, similar to the one I wrote for beta code. You would compile it with teckit_compile, and activate it with the Mapping= font feature of fontspec.
Among other differences, Teubner codes can contain LICR macros such as \~{e}, which would generate combining accents, and these must be normalized to NFC form to work correctly.
Alan Xiang has proposed an answer using Lua, which I haven’t tested.
As a last resort, it is possible to load LGR fonts with luainputenc. It might be possible to continue to load teubner with those 8-bit fonts, but without knowing your requirements, I can’t tell you if this would work for you.
