urbit/pub/doc/hoon/runes/wt/wtkt.md
2015-06-19 17:16:48 -04:00

66 lines
1.1 KiB
Markdown

[wutket, `?^`, %wtkt](#wtkt)
============================
Is bunt, inverse
`?^` is a synthetic rune that evaluates `r` if `p` is equal to the
[bunt]() for its [tile](), otherwise `q` is evaluated.
Produces
--------
Twig: `[%wtkt p=wing q=twig r=twig]`
Sample
------
`p` is a [`++wing`](). `q` and `r` are [twig]()s.
Tall form
---------
?^ p
q
r
Wide form
---------
?^(p q r)
Irregular form
--------------
None
Examples
--------
~zod/try=> =(*@tas "")
%.y
~zod/try=> ?^ ""
%full
%empty
%empty
~zod/try=> ?^ "asd"
%full
%empty
%full
Here we show that `*@tas`, the bunt of `@tas` is equivalent to the empty
[`++tape`]() `""`, then use it in two `?^` cases.
~zod/try=> *(unit)
~
~zod/try=> ?^ `(unit)`~
%full
%empty
%empty
~zod/try=> ?^ `(unit)`[~ u=20]
%full
%empty
%full
Similar to the above case, we show the bunt of a [`++unit`](), which is
`~`, and test against it.