The unicode module for Automation 4 Lua contains various helper functions for working with UTF-8 encoded text.
Import this module with unicode = require 'aegisub.unicode'.
Synopsis: width = unicode.charwidth(instring, index=1)
Returns the number of bytes occupied by the UTF-8 encoded code points starting at position index in instring.
The character pointed to is assumed to be a prefix byte (i.e. the first byte of the code points).
The index parameter is optional abd defaults to 1 (one) when left out, meaning the width of the first character in instring will be returned.
Synopsis: for char in unicode.chars(instring) do ... end
Returns an iterator function for looping over all code points in the given UTF-8 encoded string.
For each iteration of the loop, char will contain a string representing the next code point in the string. This string may be more than one byte long.
Synopsis: length = unicode.len(instring)
Determine the length in code points of the given UTF-8 encoded string.
Be aware that this function does not run in constant time, but in linear time (O(N)) proportional to the number of Unicode code points in instring.
Synopsis: val = unicode.codepoint(instring)
Read the first unicode codepoint from instring.