urbit/pub/docs/dev/hoon/runes/zp/zpwt.md

zapwut, !?, %zpwt

Restrict version

!? is a synthetic rune that enforces a Hoon version restriction.

Produces

Twig: [%zpwt p=twig]

Sample

p is a twig.

Tall form

To declare code that runs only in Hoon 164K or newer:

!?  164
q

To declare code that runs only in 164K through 161K:

!?  [164 161] 
q

Wide form

None

Irregular form

None

Examples

~zod/try=> !?(264 (add 2 2))
4
~zod/try=> !?(164 (add 2 2))
4
~zod/try=> !?(163 (add 2 2))
! exit