How can I get the 'right' formatting using string.format with strings containing UTF-8 characters?
Example:
local str = "\xE2\x88\x9E"
print(utf8.len(str), string.len(str))
print(str)
print(string.format("###%-5s###", str))
print(string.format("###%-5s###", 'x'))
Output:
1 3
∞
###∞ ###
###x ###
It looks like the string.format uses the byte length of the infinity sign instead of the "character length".
Is there an UTF-8 string.format equivalent?
function utf8.format(fmt, ...)
local args, strings, pos = {...}, {}, 0
for spec in fmt:gmatch'%%.-([%a%%])' do
pos = pos + 1
local s = args[pos]
if spec == 's' and type(s) == 'string' and s ~= '' then
table.insert(strings, s)
args[pos] = '\1'..('\2'):rep(utf8.len(s)-1)
end
end
return (
fmt:format(table.unpack(args))
:gsub('\1\2*', function() return table.remove(strings, 1) end)
)
end
local str = "\xE2\x88\x9E"
print(string.format("###%-5s###", str)) --> ###∞ ###
print(string.format("###%-5s###", 'x')) --> ###x ###
print(utf8.format ("###%-5s###", str)) --> ###∞ ###
print(utf8.format ("###%-5s###", 'x')) --> ###x ###
Lua added the UTF-8 library with version 5.3 with just small functionality for minimal needs. It's "fresh" and not really in focus for this language. Your issue is how the characters are interpreted & rendered but graphics isn't a point for the standard library or usual use of Lua.
For now, you should just fix your pattern for the input.
