If you'd talked about Gylph objects instead of 'character' objects, I wouldn't have had to sit here and get all confused and indignant:)
Doc uses glyph objects to represent each character in the document. The editor builds one Glyph instance for each character in a particular style (which defines its graphical attributes); hence a character's intrinsic state consists of the character code and its style information (an index into a style table). This means only position is extrinsic making Doc fast.
Ah! They mean Fonts! How original.
Examine what is said, not who speaks.