Constructors as methods:

$t[^table::create{data
data1
data2}]

1. table cleared: ^t.create{} ^json:string[$t]

$h[ $.1[1] $.2[2] ]

2. hash kept: ^h.create[] ^json:string[$h]
   or added : ^h.create[ $.3[3] ] ^json:string[$h]
   or ignored ^h.create[$h] ^json:string[$h]

$a[1;2]

3. array kept: ^a.copy[] ^json:string[$a]
   or added: ^a.copy[ $.3[3] ] ^json:string[$a]
   or ignored ^a.copy[$a] ^json:string[$a]

4. array kept: ^a.create[] ^json:string[$a]
   or added: ^a.create[4] ^json:string[$a]
   or nested: ^a.create[$a] ^try-catch{ ^json:string[$a] }