$t[^table::create{a	b	c	a
va	vb	vc	vd}]

^t.rename[b;e]

1. ^try-catch{ $t.b }
2. $t.e

3. ^try-catch{ ^t.rename[ $.a{code} ] }

4. $t.a

^t.rename[ $.e[b] $.a[z] $.z[a] ]

5. $t.b, $t.z
6. ^try-catch{ $t.a }

7. ^try-catch{ ^t.rename[ ] }
8. ^try-catch{ ^t.rename[ z ] }
9. ^try-catch{ ^t.rename[ z ]{ z } }