# Module:Lang/name to tag

local lang_data = mw.loadData ('Module:Lang/data'); -- language name override and transliteration tool-tip tables
local lang_name_table = lang_data.lang_name_table; -- language codes, names, regions, scripts, suppressed scripts  
local lang_table = lang_name_table.lang; -- language codes, names
local lang_dep_table = lang_name_table.lang_dep; -- deprecated language codes, names
local override_table = lang_data.override;  
local rev_lang_table = {}; -- same as lang_table reversed so language name is key and language tag is value
local rev_lang_dep_table = {}; -- same as lang_dep_table reversed so language name is key and language tag is value
local rev_override_table = {}; -- same as override_table except reversed
local dedabbed_names_list = {}; -- holds a list of dedabbed name and tags  
----------------------------< R E V _ L I S T _ A D D >------------------------------------------------------  
local function to add <name> (key) and <tag> (value) pair to <rev_list>  
<name>/<tag> pairs where <tag> is ISO 639-1, overwrite all other <name>/<tag> pairs. When creating overrides,
take care that the <name> is properly disambiguated to avoid improper masking  
local function rev_list_add (rev_list, name, tag)
if rev_list[name] then -- if already in <rev_list>
if 2 == tag:len then -- is this is a 2-characater code?
rev_list[name] = tag; -- yes, overwrite 3-characater language <name> and <tag> pair in <rev_list>
end
else -- here when not yet in <rev_list>
rev_list[name] = tag; -- add language <name> and <tag> (value) pair to <rev_list>
end
end  
----------------------------< D E D A B B E D _ N A M E S _ L I S T _ A D D >--------------------------------  
adds <name>/<tag> pairs to the dedabbed_names_list when <name> not already present. When <name> is present in
the list, unsets the listed <tag> to empty string; cannot have different <name>/<tag> pairs where the table
key (<name>) is shared with another <name>/<tag> pair.  
local function dedabbed_names_list_add (dab, name, tag)
if 0 ~= dab then -- if dab was removed
if dedabbed_names_list[name] then -- if this dedabbed name is in the table then there are more than one name with different dabs
dedabbed_names_list[name] = ''; -- unset but not too unset
else
dedabbed_names_list[name] = tag; -- add name / tag pair in case this the only dedabbed name
end
end
end  
----------------------------< D E D A B B E D _ T O _ R E V _ L I S T _ A D D >------------------------------  
adds <name>/<tag> pairs to specified <rev_list> when <tag> is not empty string  
local function dedabbed_to_rev_list_add (rev_list, name, tag)
for name, tag in pairs (dedabbed_names_list) do -- add dedabbed <name>/<tag> pairs to the reversed table
if '' ~= tag then -- when <name>/<tag> has not been unset because of multiple dabs
rev_list_add (rev_list, name, tag); -- add
end
end
end  
--[[--------------------------< T A G - F R O M - N A M E D A T A >------------------------------------------  
Creates tag-from-name tables from the data in Module:Lang/data so that templates can get language tags from the
same names as the templates get from those tags. The conversion prefers ISO 639-1 codes.  
Data in these tables are used by tag_from_name in Module:Lang  
When <name> is disambiguated, will create an additional <name> entry without the dab as long as that action won't
conflict with actual undabbed names in the source.  
<name> without dab is always added to the list; this rule arises because of the three Marwari language code/name pairs:
mwr: Marwari -– not dabbed
these will not have dedabbed entries because of mwr
rwr: Marwari (India)
mve: Marwari (Pakistan)  
These all share the same base name so there will not not be an dedabbed entry:
["yaka"] = "axk", -- this would be wrong for two of these languages
["yaka (central african republic)"] = "axk",
["yaka (congo)"] = "iyx",
["yaka (democratic republic of congo)"] = "yaf",  
Say that we find "axk". It has a dab so we add the dabbed form to rev_lang_table{}. Then we look in
dedabbed_names_list{} to see if ["yaka"] is already there. It's not, so we add this:
["yaka"] = "axk",
Later we find "yaf". It has a dab so we add the dabbed form to rev_lang_table{}. Then we look in
dedabbed_names_list{} to see if ["yaka"] is already there. It is, so that means that more than one language
code could create an dedabbed language name key; there can be only one. Because ["yaka"] is already in the
dedabbed_names_list{} table we unset the ["yaka"] entry to empty string:
["yaka"] = '',
later we find "iyx" and add it to rev_lang_table{}. We look in dedabbed_names_list{} and find ["yaka"] has been
unset to empty string so do nothing.  
When done adding names/codes to rev_lang_table{}, spin through dedabbed_names_list{} and add all non-empty-string
name/code pairs to rev_lang_table{}.  
This does not catch things like overrides ["pa"] = "Punjabi" and ["pnb"] = "Punjabi". "pa" and "pnb" are not
synonyms but because the names are the same, will be treated like synonyms ("pnb" promotes to "pa"). To avoid
this, disambiguate the override: ["pnb"] = {"Punjabi"} -> ["pnb"] = {"Punjabi (Western)"}  
for tag, name_table in pairs (lang_table) do
if not override_table[tag] then -- only add names/tags from name_table when tag not present in override table
local name_raw = name_table:lower;
local name, dab = name_raw:gsub ('%s+%b', ''); -- remove parenthetical disambiguators or qualifiers from names that have them; <dab> non-zero when disambiguation removed  
rev_list_add (rev_lang_table, name_raw, tag); -- add no-dab-names and names-with-dab here
dedabbed_names_list_add (dab, name, tag); -- add to dedabbed_names_list if dabbed
end
end  
dedabbed_to_rev_list_add (rev_lang_table, name, tag); -- add dedabbed name/tag pairs to the reversed table  
dedabbed_names_list = {}; -- reset list of dedabbed names  
for tag, name_table in pairs (lang_dep_table) do
if not override_table[tag] then -- only add names/tags from name_table when tag not present in override table
local name_raw = name_table:lower;
local name, dab = name_raw:gsub ('%s+%b', ''); -- remove parenthetical disambiguators or qualifiers from names that have them; <dab> non-zero when disambiguation removed  
rev_list_add (rev_lang_dep_table, name_raw, tag); -- add no-dab-names and names-with-dab here
dedabbed_names_list_add (dab, name, tag); -- add to dedabbed_names_list if dabbed
end
end  
dedabbed_to_rev_list_add (rev_lang_dep_table, name, tag); -- add dedabbed name/tag pairs to the reversed table  
dedabbed_names_list = {}; -- reset list of dedabbed names  
for tag, name_table in pairs (override_table) do
local name_raw = name_table:lower;
local name, dab = name_raw:gsub ('%s+%b', ''); -- remove parenthetical disambiguators or qualifiers from names that have them  
rev_list_add (rev_override_table, name_raw, tag);
dedabbed_names_list_add (dab, name, tag); -- add to dedabbed_names_list if dabbed
end  
dedabbed_to_rev_list_add (rev_override_table, name, tag); -- add dedabbed name/tag pairs to the reversed table  
dedabbed_names_list = {}; -- reset list  
----------------------------< E X P O R T E D T A B L E S >------------------------------------------------  
return {
rev_lang_table = rev_lang_table,
rev_lang_dep_table = rev_lang_dep_table,
rev_override_table = rev_override_table,
}