"translating" One character to another in lua

I want to make a lua script that takes the input of a table, then outputs the strings in that table in their full width counterparts, eg

input = {"Hello", " ", "World"}
print(full(table.concat(input)))

and it will print "Ｈｅｌｌｏ　Ｗｏｒｌｄ"

I tried it using this:

local encoding = [[　０１２３４５６７８９ａｂｃｄｅｆｇｈｉｊｋｌｍｎｏｐｑｒｓｔｕｖｗｘｙｚＡＢＣＤＥＦＧＨＩＪＫＬＭＮＯＰＱＲＳＴＵＶＷＸＹＺ！゛＃＄％＆（）＊＋、ー。／：；〈＝〉？＠［\\］＾＿‘｛｜｝～]]
function char(i)
   return encoding:sub(i:len(),i:len())
end
function decode(t)
   for i=1,#t do t[i]=char(t[i]) end
   return table.concat(t)
end
function returns(word, word_eol)
    print(char(word_eol[2]))
end

but that did not work

note: it is a plugin for hexchat that's why I have it as print(char(word_eol[2])))

Because when you hook a command in hexchat it spits out a table that is the command name, then what was entered after

Solution

If (string) = [[　０１２３４５６７８９ａｂｃｄｅｆｇｈｉｊｋｌｍｎｏｐｑｒｓｔｕｖｗｘｙｚＡＢＣＤＥＦＧＨＩＪＫＬＭＮＯＰＱＲＳＴＵＶＷＸＹＺ！゛＃＄％＆（）＊＋、ー。／：；〈＝〉？＠［\］＾＿‘｛｜｝～]], you're finding the n th character of (string), with n being the length of the character, which will always be one. If I understand correctly, this will do the job, by having a separate alphabet and matching the characters.

local encoding = [[　０１２３４５６７８９ａｂｃｄｅｆｇｈｉｊｋｌｍｎｏｐｑｒｓｔｕｖｗｘｙｚＡＢＣＤＥＦＧＨＩＪＫＬＭＮＯＰＱＲＳＴＵＶＷＸＹＺ！゛＃＄％＆（）＊＋、ー。／：；〈＝〉？＠［］＾＿‘｛｜｝～]]
local decoding = [[ 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&()*+,-./:;{=}?@[]^_'{|}~]]
function char(i)
   local l = decoding:find(i,1,true)
   return encoding:sub(l,l)
end
function decode(t)
   for i=1,#t do t[i]=char(t[i]) end
   return table.concat(t)
end
function returns(word, word_eol)
    print(char(word_eol[2]))
end