The phrase h=: f : g defines h as the function whose monadic case is f and whose dyadic case is g . The components f and g may be functions already defined and named, or they may be tacit or explicit phrases. Moreover, either (but not both) may be defined in terms of the other by using $: for self-reference in a tacit definition.
|v0=: 10&^. : ^.||Base 10 log for monadic case|
|v1=: 10&$: : ^.||Same using self-reference to dyad|
|v2=: 10&^. : ($:@] * ^.@(10"0) % ^.@[)||Same using self-reference to monad|
|d3=: res=: [: : |||Domain of monad is empty (dyadic only)|
|m4=: abs=: | : [:||Domain of dyad is empty (monadic only)|