Similar to the LaTeX() converter, you can use either tt(NOTRANS) or
tt(htmlcommand) to send HTML commands to the output. Or, since the only 
`difficult' characters are probably only tt(<) and tt(>), you can also resort 
to tt(CHAR) for these two characters.

Furthermore, the HTML converter defines the macro tt(htmltag), expecting two 
arguments: the tag to set, and an `on/off' switch. E.g., tt(htmltag(b)(1)) 
sets tt(<b>) while tt(htmltag(b)(0)) sets tt(</b>).

E.g., the following code sends a HTML command tt(<hr>) to the output file when 
in HTML mode:
        verb(\
    COMMENT(-- alternative 1, using htmlcommand --)
    htmlcommand(<hr>)
    
    COMMENT(-- alternative 2, using NOTRANS --)
    IFDEF(html)(
        NOTRANS(<hr>)
    )()
    
    COMMENT(-- alternative 3, using CHAR --)
    IFDEF(html)(
        CHAR(C)HAR(<)hr+CHAR(C)HAR(>)
    )()
        
    COMMENT(-- alternative 4, using htmltag --)
    htmltag(hr)(1)
        )