I'm trying to declare a new font style. I declare it with \definefontstyle [sx] [sx] but the compilation fails when I use \sx in my document.
\definefontstyle [sx] [sx]
\definetypeface [source] [sx] [semiextended] [myriadpro] [optical]
\starttypescript [semiextended] [optical] [size]
\definebodyfont [11pt] [sx] [tf=SansSemiExtended sa 1]
\stoptypescript
\starttypescript [semiextended] [myriadpro]
\definefontsynonym [SansSemiExtended] [file:MyriadPro-SemiExt.otf] [features=default]
\stoptypescript
\starttext
{\sx ABCDEFGHIJKLM\par
NOPQRSTUVWXYZ\par
abcdefghijklm\par
nopqrstuvwxyz\par
1234567890}
\stoptext
Antoine C.