Dyadic defn

Dynamically defines a function.

Syntax: <x> defn <y>; defn[<x>; <y>]

whеre x is a symbol vector with argument names, and y is a list of expressions.

o)f:defn[`a`b;,(+;`a;`b)]
{[`a`b]((+;a;b))}
o)f[1;2]
3
o)