Thun/docs/reference/dupdip.md

Combinator Apply a function `F` and [dup] the item under it on the stack. a [F] dupdip

## dupdip Combinator Apply a function F and [dup] the item under it on the stack. a [F] dupdip

      a F a

Definition

[dupd] [dip]

Derivation

a [F] dupdip
a [F] dupd dip
a [F] [dup] dip dip
a dup [F] dip
a a [F] dip
a F a

Discussion

A very common and useful combinator.

Crosslinks

[dupdipd]