prefix<O, V> method
Adds a prefix operator parser
. Evaluates the optional action
with the
parsed operator
and value
.
Implementation
void prefix<O, V>(Parser<O> parser,
[dynamic Function(O operator, V value)? action]) {
final callback = action ?? (operator, value) => [operator, value];
_prefix.add(parser.map((operator) => ExpressionResult(operator, callback)));
}