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136 lines
3.9 KiB
Markdown
136 lines
3.9 KiB
Markdown
barcen, `|%`, %brcn
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============================
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Build Core
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`|%` is a natural rune that produces a [core](). `|%` takes a list of
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[arm]()s . The list must be closed with a `--`.
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The product of `|%` is similar to an object with named properties
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containing either functions or data. A `|%` accepts both [dry or
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`%elm`]() and [wet or `%ash`]() arms. For more about variance, see the
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[glossary]().
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See also
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--------
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[barcab, `|_`, `%brcb`]() [barfas, `|/`, `%brfs`]()
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Produces
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--------
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Twig: `[%brcn p=(map term foot)]`
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Sample
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------
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`p` is a [`map`]() with [`++term`]() keys and [`++foot`]() values, which
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are called arms.
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Tall form
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---------
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|%
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++ p.n.q
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q.n.q
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+- p.n.l.q
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q.n.l.q
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--
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Wide form
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---------
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None
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Irregular form
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--------------
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None
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Examples
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--------
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/~zod/try=>
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=a |%
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++ n 100
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++ g |= b=@
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(add b n)
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--
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new var %a
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/~zod/try=>
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(g.a 1)
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101
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Here we create a core with two arms `n`, a constant and `g`, a simple
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funciton. `g` adds our constant `n` to whatever is passed to it.
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/~zod/try=>
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=a |%
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++ l |%
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++ r 100
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++ s 4
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--
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++ g |= b=@
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(div (add b r:l) s:l)
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--
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changed %a
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/~zod/try=>
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(g.a 4)
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26
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Extending our previous example a bit, we nest a core inside our arm `l`
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and make our [gate]() `g` a bit more complicated. `g` now computes the
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sum of its argument and the arm `r` inside `l`, and divides that by `s`
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inside `l`.
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++ yo
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|% ++ cet 36.524 :: (add 24 (mul 100 365))
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++ day 86.400 :: (mul 24 hor)
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++ era 146.097 :: (add 1 (mul 4 cet))
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++ hor 3.600 :: (mul 60 mit)
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++ jes 106.751.991.084.417 :: (mul 730.692.561 era)
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++ mit 60
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++ moh `(list ,@ud)`[31 28 31 30 31 30 31 31 30 31 30 31 ~]
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++ moy `(list ,@ud)`[31 29 31 30 31 30 31 31 30 31 30 31 ~]
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++ qad 126.144.001 :: (add 1 (mul 4 yer))
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++ yer 31.536.000 :: (mul 365 day)
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--
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[`++yo`](), found in `hoon.hoon`, uses `|%` to create a core whose arms
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contain constant data for calculating time. As the following examples
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shows, `|%` is also used to encapsulate arms that perform calculations.
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++ si :: signed integer
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|%
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++ abs |=(a=@s (add (end 0 1 a) (rsh 0 1 a)))
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++ dif |=([a=@s b=@s] (sum a (new !(syn b) (abs b))))
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++ dul |=([a=@s b=@] =+(c=(old a) ?:(-.c (mod +.c b) (sub b +.c))))
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++ fra |= [a=@s b=@s]
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(new =(0 (mix (syn a) (syn b))) (div (abs a) (abs b)))
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++ new |=([a=? b=@] `@s`?:(a (mul 2 b) ?:(=(0 b) 0 +((mul 2 (dec b))))))
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++ old |=(a=@s [(syn a) (abs a)])
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++ pro |= [a=@s b=@s]
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(new =(0 (mix (syn a) (syn b))) (mul (abs a) (abs b)))
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++ rem |=([a=@s b=@s] (dif a (pro b (fra a b))))
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++ sum |= [a=@s b=@s]
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~| %si-sum
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=+ [c=(old a) d=(old b)]
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?: -.c
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?: -.d
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(new & (add +.c +.d))
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?: (gte +.c +.d)
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(new & (sub +.c +.d))
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(new | (sub +.d +.c))
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?: -.d
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?: (gte +.c +.d)
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(new | (sub +.c +.d))
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(new & (sub +.d +.c))
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(new | (add +.c +.d))
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++ sun |=(a=@u (mul 2 a))
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++ syn |=(a=@s =(0 (end 0 1 a)))
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--
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[`++si`](), found in `hoon.hoon`, uses `|%` to create a core whose arms
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contain gates used to calculate with signed integers, [`@s`](). In this
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case our core is made up entirely of gates.
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