case Tree("<-", _ ,_) => Seq(new GlyphText(LeftArrow))
case Tree("<=", _ ,_) => Seq(new GlyphText(DoubleLeftArrow))
case Tree("=>", _ ,_) => Seq(new GlyphText(DoubleRightArrow))
case Tree("<-", _ ,_) => Seq(new GlyphText(LeftArrow))
case Tree("<=", _ ,_) => Seq(new GlyphText(DoubleLeftArrow))
case Tree("=>", _ ,_) => Seq(new GlyphText(DoubleRightArrow))