On Fri, 11 Nov 2011, Steffen Wolfrum wrote:

> quite often I wish we could have a kind of in line comment:
> Something like ¿this is my comment¡ this.
>
> I assume it is not trivial due to catcode issues, to say the least.
> But nevertheless, as it is getting close to christmas, I just wanted to mention this idea here.

As long as there is no line break in the comment, the following lua based 
solution works (inspired by m-translate)

\startluacode
   local comments = {}
   thirddata = thirddata or {}

   thirddata.comments = comments

   function comments.translate(s)
       return string.gsub(s, "¿.-¡","")
   end

   local textlineactions = resolvers.openers.helpers.textlineactions
   utilities.sequencers.appendaction(textlineactions,"after","thirddata.comments.translate")

   function comments.enable()
     utilities.sequencers.enableaction(textlineactions,"thirddata.comments.translate")
   end

   function comments.disable()
     utilities.sequencers.disableaction(textlineactions,"thirddata.comments.translate")
   end

   comments.disable()
\stopluacode

\def\enablecomments {\ctxlua{thirddata.comments.enable()}}
\def\disablecomments{\ctxlua{thirddata.comments.disable()}}

\appendtoks
   \enablecomments
   \to \everystarttext

\starttext
\section{An ¿in \iffalse comment¡ works}
Multiple ¿in \iffalse comment¡ with something  ¿in \iffalse comment¡ in betweeen
\stoptext

Aditya