utf8.*

Overview

The UTF-8 plugin, based on the luautf8 module, provides functions to manipulate UTF-8 strings in Corona.

UTF-8 strings are composed of a mixture of single-byte and multi-byte Unicode characters which means that simple byte counting can’t be used to determine things like string length or substring positions. The Lua string object can store UTF-8 strings since it just considers them to be a sequence of bytes, but any operation that needs to understand the concept of a “character” won’t work because Lua assumes all characters are one byte.

Essentially, if you need to handle actions like upper-casing or string substitutions with accented or non-ASCII characters, this plugin will be especially useful.

Concepts

The UTF-8 plugin uses some concepts which should be understood before attempting to use it.

• character position or charpos — The position of a character in the UTF-8 string relative to the start of the string. The position of any character depends on the width (number of bytes) of all characters preceding it.

• offset or offset — The number of characters that one character is from another. This may depend on the characters which exist between the two points.

• code point or codepoint — Number which represents the character at a particular charpos. It is the Unicode standard code for that character.

Syntax

local utf8 = require( "plugin.utf8" )

Functions

Project Settings

To use this plugin, add an entry into the plugins table of build.settings. When added, the build server will integrate the plugin during the build phase.

settings =
{
    plugins =
    {
        ["plugin.utf8"] =
        {
            publisherId = "com.coronalabs"
        },
    },      
}