Info Catalog groff: Using Symbols groff: Fonts and Symbols groff: Special Fonts

groff: Character Classes

 
 5.17.5 Character Classes
 ------------------------
 
 Classes are particularly useful for East Asian languages such as
 Chinese, Japanese, and Korean, where the number of needed characters is
 much larger than in European languages, and where large sets of
 characters share the same properties.
 
  -- Request: .class n c1 c2 ...
      In 'groff', a "character class" (or simply "class") is a set of
      characters, grouped by some user aspect.  The 'class' request
      defines such classes so that other requests can refer to all
      characters belonging to this set with a single class name.
      Currently, only the 'cflags' request can handle character classes.
 
      A 'class' request takes a class name followed by a list of
      entities.  In its simplest form, the entities are characters or
      symbols:
 
           .class [prepunct] , : ; > }
 
      Since class and glyph names share the same namespace, it is
      recommended to start and end the class name with '[' and ']',
      respectively, to avoid collisions with normal 'groff' symbols (and
      symbols defined by the user).  In particular, the presence of ']'
      in the symbol name intentionally prevents the usage of '\[...]',
      thus you must use the '\C' escape to access a class with such a
      name.
 
      You can also use a special character range notation, consisting of
      a start character or symbol, followed by '-', and an end character
      or symbol.  Internally, 'gtroff' converts these two symbol names to
      Unicode values (according to the groff glyph gist), which then give
      the start and end value of the range.  If that fails, the class
      definition is skipped.
 
      Finally, classes can be nested, too.
 
      Here is a more complex example:
 
           .class [prepunctx] \C'[prepunct]' \[u2013]-\[u2016]
 
      The class 'prepunctx' now contains the contents of the class
      'prepunct' as defined above (the set ', : ; > }'), and characters
      in the range between 'U+2013' and 'U+2016'.
 
      If you want to add '-' to a class, it must be the first character
      value in the argument list, otherwise it gets misinterpreted as a
      range.
 
      Note that it is not possible to use class names within range
      definitions.
 
      Typical use of the 'class' request is to control line-breaking and
      hyphenation rules as defined by the 'cflags' request.  For example,
      to inhibit line breaks before the characters belonging to the
      'prepunctx' class, you can write:
 
           .cflags 2 \C'[prepunctx]'
 
      See the 'cflags' request in ⇒Using Symbols, for more
      details.
 

Info Catalog groff: Using Symbols groff: Fonts and Symbols groff: Special Fonts