shrub/pub/doc/hoon/runes/sm/smcl.md
2015-06-19 17:16:48 -04:00

1.1 KiB

semcol, ;:, %smcl

Apply fold

Syntax

;: is a synthetic hoon that applies p, a binary gate, to the n-ary tuple q. ;: is similar to folding over the tuple q, producing the final result.

Produces

Twig: [%smcl p=twig q=tusk]

Sample

p is a twig. q is a ++tusk.

Tall form

;:  p
  i.q
  i.t.q
  i.t.t.q
==

Wide form

;:(p i.q i.t.q i.t.t.q)

Irregular form

:(p i.q i.t.q i.t.t.q)

Examples

~zod/try=> (add 3 (add 4 5))
12
~zod/try=> ;:(add 3 4 5)
12
~zod/try=> :(add 3 4 5)
12

Here we see how ;: is equivalent to nesting our calls to the binary gate ++add.

~zod/try=> :(weld "foo" "bar" "baz")
~[~~f ~~o ~~o ~~b ~~a ~~r ~~b ~~a ~~z]
~zod/try=> `tape`:(weld "foo" "bar" "baz")
"foobarbaz"
~zod/try=> `tape`(weld "foo" (weld "bar" "baz"))
"foobarbaz"

Following on from our previous example, using ;: with ++weld is convenient for concatenating multiple strings.