g can be any monadic function which returns a result. Y can be any array appropriate to function g with gY being suitable as the right argument to function f.
If X is omitted, f must be a monadic function. If X is specified, f must be a dyadic function and X can be any array that is suitable as the left argument to function f.
The derived function is equivalent to fgY or XfgY and need not return a result.
The Beside operator allows functions to be glued together to build up more complex functions. For further information, see Function Composition.
Examples
RANK ← ⍴∘⍴ RANK ¨ 'JOANNE' (2 3⍴⍳6) 1 2
+/∘⍳¨2 4 6 3 10 21 ⎕VR'SUM' ∇ R←SUM X [1] R←+/X ∇ SUM∘⍳¨2 4 6 3 10 21
+∘÷/40⍴1 ⍝ Golden Ratio! (Bob Smith) 1.618033989 0,∘⍳¨⍳5 0 1 0 1 2 0 1 2 3 0 1 2 3 4 0 1 2 3 4 5