urbit/docs/pub/doc/hoon/runes/ts/tsdt.md

tisdot, =., %tsdt

Single change subject

=. is a synthetic hoon that produces r with p in the subject set to q.

Produces

Twig: [%tsdt p=wing q=twig r=twig]

Sample

p is a wing. q and r are twigs.

Tall form

Kingside:

=.  p 
  q
r

Queenside:

=.  p  q
r

Wide form

=.(p q r)

Irregular form

None

Examples

~zod/try=> =+  a=[b=1 c=2]
           =.  b.a  3
           a
[b=3 c=2]
~zod/try=> =+  a=[b=1 c=2]
           =.(b.a 3 a)
[b=3 c=2]

Here we see the tall and wide forms of =. used to manipulate our simple subject a=[b=1 c=2].