Help understanding QLexers

[Andrea]

Hi

I am trying to understand how to create a new QLexer for a new language.

Looking at all existing lexers they have an anonymous enum which links some integers 0, 1 to 
symbolic names.

Example:

     //! This enum defines the meanings of the different styles used by the
     //! Lua lexer.
     enum {
         //! The default.
         Default = 0,

         //! A block comment.
         Comment = 1,

         //! A line comment.
         LineComment = 2,

         //! A number.
         Number = 4,

The problem I have is that I cannot understand how the interface uses these private values to call 
functions like

QColor QsciLexerLua::defaultColor(int style) const
{
     switch (style)
     {
     case Default:
         return QColor(0x00,0x00,0x00);

     case Comment:
     case LineComment:
         return QColor(0x00,0x7f,0x00);

     case Number:
         return QColor(0x00,0x7f,0x7f);

How does the scidocument know that we have decided that a Number is 4?
Or that a Comment is 1?

Not all lexers share the same ids for the common values.
In other words, I can reassign the numbers in the enum and I do not see how the "caller" could be aware.
I was expecting that some of the interface functions returned these values, but I could not find any.

Cheers