\startcomponent ma-cb-en-usersetups

\enablemode[**en-us]

\project ma-cb

\startchapter[title=User specifications]

\index{preamble}
\index{input file}

The setup area of your document is the area before
the \type{\starttext} command. For example:

\setuptyping
    [escape=yes]

\definestartstop
    [comment][style={\rm}]

\starttyping
                                   /BTEX \comment{first line of your file} /ETEX
\setuplayout[width=25cm]           /BTEX \comment{set the width of your text} /ETEX
                                   /BTEX \comment{empty line for readability} /ETEX
\starttext                         /BTEX \comment{starts your text} /ETEX
Hello Hasselt.                     /BTEX \comment{your text} /ETEX
\stoptext                          /BTEX \comment{ends your text} /ETEX
\stoptyping

Note that the first line of this file is empty. However, this first line
is a preamble and can be used for specific user specifications. For example:

\starttyping
% engine=luatex                    /BTEX \comment{use the \type{luatex} engine} /ETEX
                                   /BTEX \comment{empty line for readability} /ETEX
\setuplayout[width=25cm]           /BTEX \comment{set the width of your text} /ETEX
                                   /BTEX \comment{empty line for readability} /ETEX
\starttext                         /BTEX \comment{starts your text} /ETEX
Hello Hasselt.                     /BTEX \comment{your text} /ETEX
\stoptext                          /BTEX \comment{ends your text} /ETEX
\stoptyping

Note that \CONTEXT\ sees the text after the \type{ % }
sign in this first line not as a comment.

The preamble can have a meaning for both \CONTEXT\ and \SCITE:

\starttyping
% engine=pdftex interface=en modes=screen language=us

\starttext
Hello Hasselt.
\stoptext
\stoptyping

This will be interpreted as:

\starttabulate[|T||p|]
\NC engine=pdftex \NC \CONTEXT \EQ run as \PDFTEX \NC\NR
\NC interface=en  \NC \CONTEXT \EQ expect english \CONTEXT\ commands (lexing) \NC\NR
\NC               \NC \SCITE   \EQ use english lexing \NC\NR
\NC modes=screen  \NC \CONTEXT \EQ invoke mode \type{screen} that is set in the text \NC\NR
\NC language=uk   \NC \SCITE   \EQ use the english spell checker \NC\NR
\stoptabulate

\stopchapter

\stopcomponent