我使用的是XeTeX 3.1415926-2.2-0.9997.4（TeX Live 2010的一部分）。它的一个新功能是字符突出，我想在我的文档中使用它。问题是我无法使其发挥作用。
来自xetex.tk wiki的XeTeX sample正确编译并显示突出的字符。虽然我创建的XeLaTeX文件根本没有显示任何突出。
任何人都能告诉我我做错了什么吗？
\documentclass[12pt]{book}
\usepackage{xltxtra}
\usepackage{polyglossia}
\setmainfont[Mapping=tex-text]{Charis SIL}
\setmainlanguage{english}
\def\setprotcode#1{
\rpcode#1 U"0021 55
\rpcode#1 U"002C 194
\rpcode#1 U"002D 233
\rpcode#1 U"002E 194
\rpcode#1 U"003B 138
\rpcode#1 U"003A 138
\rpcode#1 U"003F 94
\lpcode#1 U"2018 194
\rpcode#1 U"2019 194
\lpcode#1 U"201C 250
\rpcode#1 U"201D 250
\rpcode#1 U"2013 150
\rpcode#1 U"2014 200
}
\XeTeXprotrudechars=2
\font\f = "Charis SIL:mapping=tex-text"
\setprotcode{\f}
\begin{document}
In a genetic algorithm, a population of strings (called chromosomes or the
genotype of the genome), which encode candidate solutions (called individuals,
creatures, or phenotypes) to an optimization problem, evolves toward better solutions.
Traditionally, solutions are represented in binary as strings of 0s and 1s, but other
encodings are also possible. The evolution usually starts from a population of randomly
generated individuals and happens in generations. In each generation, the fitness of
every individual in the population is evaluated, multiple individuals are
stochastically selected from the current population (based on their fitness),
and modified (recombined and possibly randomly mutated) to form a new population.
The new population is then used in the next iteration of the algorithm. Commonly,
the algorithm terminates when either a maximum number of generations has been produced,
or a satisfactory fitness level has been reached for the population. If the algorithm
has terminated due to a maximum number of generations, a satisfactory solution may or
may not have been reached.
\end{document}