\showframe

\definenarrower[whatever][left=3cm,right=2cm,default=left]

\starttext

\input ward

\startnarrower[2*left] \input ward \stopnarrower

\input ward

\startnarrow[whatever] \input ward \stopnarrow

\input ward

\startnarrow[whatever][right] \input ward \stopnarrow

\input ward

\startnarrow[whatever][default=middle] \input ward \stopnarrow

\input ward

\startnarrow[whatever][default=middle,middle=-1cm] \input ward \stopnarrow

\input ward

\startnarrow[default=middle] \input ward \stopnarrow

\input ward

\stoptext
