\lstdefinelanguage{ETL}{
morekeywords={import, pre, post, var, rule, to, extends, not, with, guard, match, merge, transform, for, in, and, or, self, operation, return, def, if, new, else, match, compare, conform, into, switch, case, default},
sensitive=true,
morecomment=[l]{//},
morecomment=[s]{/*}{*/},
morestring=[b]",
showstringspaces=false
}