Unicode Explained

better tools exist. You could use the small letter “a” with macron (ā), or you could use

“a” followed by a combining macron, or you could use a formula editor.

Additional no-break space characters

The character U+202F , narrow no-break space, would appear to address some com-

mon problems in spacing, since it is both narrow and nonbreaking. However, support

to it in programs and fonts is still rather limited. It was included in Unicode (in Version

3.0) for special purposes: for use in the Mongolian script. It has been defined just as

being narrower than a no-break space, without specifying the width, so it cannot give

any precise control even in principle.

Finally, there is U+FEFF, zero-width no-break space (ZWNBSP). As its name suggests,

it is really an invisible connector. It would prevent a line break inside a string even if a

break would otherwise be permitted. The recommended character for such usage is

now U+2060, word joiner (WJ). The reason is that ZWNBSP also has a different usage:

it is used as a byte order mark (see Chapter 6). However, in practice, ZWNBSP is more

widely supported in software at present.

In theory, you could use a “nonbreakable thin space” (e.g., between numbers) by using

a thin space followed by a word joiner, U+2009 U+2060. In addition to being clumsy,

this would be unreliable, since it uses two characters that are not widely supported.

Far too often, U+2060 displays ...