Matches an expression against a series of case/value pairs and returns the value for the first match.
Arguments after the expression are provided in pairs: case1, value1, case2, value2, .... If the total number of remaining arguments is odd,
the last argument is used as a default. Returns null if nothing
matches and no default is given.
Examples
switch(status, 'active', 'Running', 'paused', 'Paused', 'Unknown')
→ 'Running' (when status is 'active')
→ 'Unknown' (when status is 'archived')
switch('B', 'A', 1, 'B', 2, 'C', 3) → 2
switch('D', 'A', 1, 'B', 2) → null