then
open infix fun <Output> Expression<Boolean>.then(output: Expression<Output>): ExpressionScope.CaseBranch<Output>
open infix fun <Output> String.then(output: Expression<Output>): ExpressionScope.MatchBranch<String, Output>
open infix fun <Output> Number.then(output: Expression<Output>): ExpressionScope.MatchBranch<Number, Output>
open infix fun <Output> List<String>.then(output: Expression<Output>): ExpressionScope.MatchBranch<String, Output>
open infix fun <Output> List<Number>.then(output: Expression<Output>): ExpressionScope.MatchBranch<Number, Output>