GNU Info

(enscript.info)Writing New Highlighting Definitions

---

Next: Index Prev: The states Program Up: Top

---

Enter node , (file) or (file)node

Writing New Highlighting Definitions
************************************

   The highlighting works in three separate phases.  First, the
"highlighing rules" process the input stream and parse it into logical
components.  The components are called "faces".  A face presents one
logical component of the input language, for example, a keyword, a
comment, etc..  The enscript's highlighting model defines the following
faces:

bold
italic
bold_italic
     Hard-coded faces for the bold, italic, and bold-italice text types.
     These faces define the exact presentation of the face font, so the
     style files have very little power in customizing their outlook.
     These faces should be avoided as much as possible.

comment
     A comment, normally in a programming language.

function_name
     A function name.  The function names are normally recognized from
     function definitions, not from an use of the function.

variable_name
     A variable name.  The variable names are normally recognized from
     function, type, and variable definitions.

keyword
     A reserved keyword.  Normally, all occurrences of the keywords are
     recognized.

reference
     A reference to another location in a file or to another file or
     resource.  For example, in the C-language, the goto targets are
     references.

string
     A string literal.

builtin
     A builtin function or property.  Normally, all occurrences of the
     builtins are recognized.

type
     A type specifier.  The types are normally recognized from function,
     type, and variable definitions.

   As the second step, the "output style" specifies how the faces are
presented in the generated output.  Each face has the following
properties:

fontname
     The PostScript font name of the the font that is used for the face.
     This property is used only for the PostScript outputs.

boldp
     A boolean flag which tells whether the face should be printed in
     bold font.  This property is used for all output languages except
     for the PostScript which uses the fontname property.

italicp
     A boolean flag which tells whether the face shuold be printed with
     italic font.  This property is used for all output languages
     except for the PostScript which uses the fontname property.

fg_color
     The foreground color of the face.

bg_color
     The background color of the face.  This property is not
     implemented on all output languages.

   Finally, the "output language" describes how the faces and other
text are presented in the output language.  The output language defines
a set of functions which are called to generate the output.

Highlighting Rules

Styles

Output Languages