使用 DocBook V4.x 和 DTD,我可以创建一个实体:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY mdash "—">
]>
<article>
...
<title>Em dash</title>
<para>The em dash is perhaps the most versatile punctuation mark.
Depending on the context, the em dash can take the place of commas,
parentheses, or colons—in each case to slightly different effect.</para>
...
</article>
我如何使用 RELAX NG 模式对 DocBook V5.0 做同样的事情?:
<?xml version='1.0' encoding='utf-8'?>
<article xmlns='http://docbook.org/ns/docbook' version='5.0' xml:lang='en'>
...
<title>Em dash</title>
<para>The em dash is perhaps the most versatile punctuation mark.
Depending on the context, the em dash can take the place of commas,
parentheses, or colons—in each case to slightly different effect.</para>