toHtml (GlyphText DoubleLeftArrow) = "&#;" -- FIXME
toHtml (GlyphText DoubleRightArrow) = "&#;" -- FIXME
toHtml (GlyphText DoubleLeftRightArrow) = "&#;" -- FIXME
toHtml (GlyphText DoubleLeftArrow) = "&#;" -- FIXME
toHtml (GlyphText DoubleRightArrow) = "&#;" -- FIXME
toHtml (GlyphText DoubleLeftRightArrow) = "&#;" -- FIXME