There is more to it then a preference for \crlf, typescript loading introduces a lot of spurious white, that not always can be made to disappear. I tracked it down to a macro in type-ini.mkvi:

\def\font_typescript_process_typescript_file_and_store
  {*\expandafter\let\expandafter\t_font_typescripts\csname\??typescriptfiles\currenttypefile\endcsname
   A\ifx\t_font_typescripts\relax
     B\font_typescript_process_typescript_store_indeed
   C\fi
   D\the\t_font_typescripts}

The ABCD*'s were added to see what happens. See the screen shot from one of my tests (<br/> results in \crlf but does not sit between text and fontswitch \switchtobodyfont). My guess is that the token register \t_font_typescripts is the source of the spaces, but I am not further than that. I have already mailed Hans Hagen about these findings.

[cid:AE3D66B6-9CD5-4377-B68D-AED490D0487E@fritz.box]

Hans van der Meer

On 2 May 2013, at 11:17 PM, Wolfgang Schuster <schuster.wolfgang@gmail.com<mailto:schuster.wolfgang@gmail.com>>
 wrote:


Am 02.05.2013 um 12:40 schrieb "Meer, H. van der" <H.vanderMeer@uva.nl<mailto:H.vanderMeer@uva.nl>>:

A call to \switchtobodyfont introduces extra vertical spacing as can be seen in the example.
Is this intentional or is it something like a % missing somewhere in a macro?

Hans van der Meer

Sorry, flew accidentally to early away. Here the attached output.

\setuppapersize[A6][A6]
\setupbodyfont[lucidaot]
\starttext
First line.\crlf
\start
\switchtobodyfont[euler]
Font switch here.\crlf
\stop
Last line.
\hairline
First line.\crlf
\start
Font switch here.\crlf
\stop
Last line.
\stoptext

Is there a reason why you use \crlf to end the lines?

When you would end the paragraph after each line the additional line wouldn't appear.