(* ::Package:: *)
values = "
/* <integer> values */
order: 5;
order: -5;
/* Global values */
order: inherit;
order: initial;
order: revert;
order: unset;
";
all = Sort@StringCases[
values,
RegularExpression[":\\s*([a-zA-Z0-9-]+);"] :> "$1"
];
"[\"" <> StringRiffle[all, "\",\""] <> "\"].contains(&mode)"