comparisonOperator function

Implementation

Parser comparisonOperator() =>
    (string('==').trim() |
            string('!=').trim() |
            string('<=').trim() |
            string('>=').trim() |
            char('<').trim() |
            char('>').trim() |
            (string('contains') & word().not()).pick(0).trim() |
            (string('in') & word().not()).pick(0).trim())
        .labeled('comparisonOperator');