help.txt syntax-highlighting.txt                            

                           Syntax highlighting


A major mode (see major-modes.txt) might contain an entry with key :syntax.
This contains a specification of syntax of the given mode. A syntax definition
has the form

      {:style :style1
       :matchers {regex1 :context2
                  regex2 :context3}}
     :context2 {}
     :context3 {}}

A context could be like :comment or :string.
The :style is a tag defining the style. It could be :green, :string, :comment,
etc. These are mapped to colors through themes, that will be applied in a

The matchers maps regular expressions to contexts. If for example the current
context is :string, a regular expression matching a double quote might map to
another context called :plain.

The highlighter will walk through the text and apply a context to each
character, using the matchers to control when to transition from one context
to another. When contexts have been applied, the screen writer can use the
corresponding style and a theme to know which color to apply when printing.