c53507a · urbit.org · git.iko.soy

docs/system/hoon/core/twig/mold.md+2−2

compare with master

unifiedsplit

@@ -10,7 +10,7 @@ molds are often called "structures.")

10

11## Overview

12

13−While Hoon can't check this property statically, any true mold

13+While Hoon can't check this property statically, a proper mold

14is a *rectifier*: an idempotent function across all nouns. If

15the sample of a gate has span `%noun`, and its body obeys the

16constraint that for any x, `=((mold x) (mold (mold x)))`, it's a

@@ -129,7 +129,7 @@ Similarly, `%foo` is the number `7.303.014` or `0x6f.6f66`;

129Translation:

130

131```

132−{a b c}` :bank(a b c)

132+{a b c} :bank(a b c)

133a/b :coat(a b)

134?(a b c) :pick(a b c)

135_a :shoe(a)

docs/system/hoon/runes/bc/bank.mdnew file+26

@@ -0,0 +1,26 @@

1+# `:bank`, `$:`, "buccol", `{$bank p/(list moss)}`

2+

3+The product: a mold which applies the tuple `p` to its sample.

4+

5+Usage: define a record type.

6+

7+Regular form: *running*.

8+

9+Irregular form:

10+```

11+{a b c} :bank(a b c)

12+```

13+

14+Example:

15+```

16+~zod:dojo> =a :bank(p/@ud q/@tas)

17+

18+~zod:dojo> (a 33 %foo)

19+[p=33 q=%foo]

20+

21+~zod:dojo> `a`[33 %foo]

22+[p=33 q=%foo]

23+

24+~zod:dojo> $:a

25+[p=0 q=%$]

26+```

docs/system/hoon/runes/bc/bcbr.mddeleted−41

@@ -1,41 +0,0 @@

1−`$| bucbar`

2−===========

3−

4−Union between atom and cell.

5−

6−[mold]() that's a union of an atom `p` and cell `q`.

7−`$|` is similar to [`$?`](), but is more strict in that in

8−only contains one atom mold and one cell mold.

9−

10−### Produces

11−

12−A validator function that validates atoms as mold `p` and cells as mold `q`.

13−

14−### Accepts

15−

16−`p` is a `mold` of an atom and `q` is a `mold` of a cell.

17−

18−### Tall form

19−

20− $| p

21− q

22−

23−### Wide form

24−

25− $|(p q)

26−

27−### Examples

28−

29− ~zod/try=> ($|(@t [@ud @ux]) 'hello')

30− 'hello'

31− ~zod/try=> (,$|(@ [@t @ud]) 44 44)

32− [',' 44]

33− ~zod/try=> *$|(~ [~ u=@])

34− ~

35−

36− ++ list |* a=_,* :: null-terminated list

37− $|(~ [i=a t=(list a)]) ::

38−

39−In `++list`, `$|` specifies that every element in a noun that can be

40−cast to a `++list` is either the atom `~` or the cell

41−`[i=a t=(list a)]`.

docs/system/hoon/runes/bc/bccb.mddeleted−52

@@ -1,52 +0,0 @@

1−`$_ buccab`

2−===========

3−

4−Unbunt (create mold from example).

5−

6−Uses a [++twig]() `p` to produce a [mold]() for the type (span)

7−of `p`. The validator function has a default value of `p`. Used

8−when either (1) you want the default value of a mold to be

9−anything other than the standard default value ([bunt]()), or (2)

10−you are referring to a type (span) that is difficult or

11−cumbersome to describe in any way other than by example.

12−

13−Produces

14−--------

15−

16−A mold whose span is the span of `p`.

17−

18−Accepts

19−-------

20−

21−`p` is a twig.

22−

23−Tall form

24−---------

25−

26− $_ p

27−

28−Wide form

29−---------

30−

31− $_(p)

32−

33−Irregular form

34−--------------

35−

36− _p

37−

38−Examples

39−--------

40−

41− ~zod/try=> *_12

42− 12

43− ~zod/try=> *@

44− 0

45− ~zod/try=> :type; *_12

46− 12

47− @ud

48− ~zod/try=> ^-(_(add 2 2) 'a')

49− 97

50−

51−Here, see how the default value of `_12` is 12, whereas the

52−default value of `@`--the type ([span]()) of `12`--is `0`.

docs/system/hoon/runes/bc/bccl.mddeleted−44

@@ -1,44 +0,0 @@

1−`$: buccol`

2−===========

3−

4−Tuple of molds.

5−

6−Produces

7−--------

8−

9−A validator function that validates a tuple of nouns against a tuple of [mold]()s.

10−

11−Accepts

12−--------

13−

14−`p` is a list of molds.

15−

16−Tall form

17−---------

18−

19− $: i.p

20− i.t.p

21− i.t.t.p

22− ==

23−

24−Wide form

25−---------

26−

27− $:(i.p i.t.p i.t.t.p)

28−

29−Irregular form

30−--------------

31−

32− {i.p i.t.p i.t.t.p}

33−

34−Examples

35−--------

36−

37− ~zod/try=> *[1 2]

38− [%1 %2]

39− ~zod/try=> (,$:(1 2) "ham")

40− [%1 %2]

41− ~zod/try=> (,[1 2] "ham")

42− [%1 %2]

43− ~zod/try=> (,[@ 2] "ham")

44− [104 %2]

docs/system/hoon/runes/bc/bccn.mddeleted−52

@@ -1,52 +0,0 @@

1−`$% buccen`

2−====

3−

4−Tagged union.

5−

6−Produces a [mold]() of a tagged union of a list of case pairs.

7−

8−Produces

9−--------

10−

11−A validator function that uses the value's [head]() as a tag to select a mold validate the tail of the value.

12−

13−Accepts

14−-------

15−

16−A list of cells of molds whose heads must be a [cube]().

17−

18−Tall form

19−---------

20−

21− $% p

22− q

23− ==

24−

25−Examples

26−--------

27−

28− ~zod/try=> $%([%& @p] [%| @t])

29− <1.dhe [* @n <246.qra 41.uuw 374.glo 100.rip 1.ypj %164>]>

30− ~zod/try=> *$%([%& @p] [%| @t])

31− [%.y ~zod]

32− ~zod/try=> :type; *$%([%& @p] [%| @t])

33− [%.y ~zod]

34− {[%.y @p] [%.n @t]}

35− ~zod/try=> :type; *(each ,@p ,@t)

36− [%.y p=~zod]

37− {[%.y p=@p] [%.n p=@t]}

38− ~zod/try=> $%(~ [%a 1])

39− ~ <syntax error at [1 13]>

40− ~zod/try=> $%([%~ ~] [%a 1])

41− <1.yck [* @n <246.qra 41.uuw 374.glo 100.rip 1.ypj %164>]>

42− ~zod/try=> *$%([%~ ~] [%a 1])

43− [~ ~]

44−

45− ++ foot $% [%ash p=twig] :: dry, geometric

46− [%elm p=twig] :: wet, generic

47− [%oak ~] :: XX not used

48− [%yew p=(map term foot)] :: XX not used

49− ==

50−

51−In `++foot`, `$%` creates a list of possible cases. That is, a `++foot`

52−can be either `%ash`, `%elm`, `%oak` or `%yew`.

docs/system/hoon/runes/bc/bcls.mddeleted−57

@@ -1,57 +0,0 @@

1−`$+ buclus`

2−===========

3−

4−Type of function (type signature).

5−

6−Produces a [mold]() for a function that accepts `p` and produces `q`. Used when we want to use the type of a function that we do not want to compute.

7−

8−Reduces to `$_(|+(p _q))`.

9−

10−Produces

11−--------

12−

13−A mold whose [span]() is used to validate the types of functions.

14−

15−Accepts

16−-------

17−

18−`p` is the mold of the [argument]() ([sample]()) and `q` is a mold of the product.

19−

20−Tall form

21−---------

22−

23− $+ p q

24−

25−Wide form

26−---------

27−

28− $+(p q)

29−

30−Examples

31−--------

32−

33− ++ sort :: quicksort

34− ~/ %sort

35− !:

36− |* [a=(list) b=$+([* *] ?)]

37− => .(a ^.(homo a))

38− |- ^+ a

39− ?~ a ~

40− %+ weld

41− $(a (skim t.a |=(c=_i.a (b c i.a))))

42− ^+ t.a

43− [i.a $(a (skim t.a |=(c=_i.a !(b c i.a))))]

44−

45−In ++sort, `$+` is a mold for a comparator gate, which takes two nouns

46−and produces a loobean.

47−

48− ~zod/try=> |=(a=@ (add 2 a))

49− <1.sgg [a=@ [[@da @ta] [@p @ta] *''] @n <246.qra 41.uuw 374.glo 100.rip 1.ypj %164>]>

50− ~zod/try=> `$+(@ @)`|=(a=@ (add 2 a))

51− <1|crm [@ [[@da @ta] [@p @ta] *''] @n <246.qra 41.uuw 374.glo 100.rip 1.ypj %164>]>

52− ~zod/try=> +<:|=(a=@ (add 2 a))

53− a=0

54− ~zod/try=> +<:`$+(@ @)`|=(a=@ (add 2 a))

55− ! -axis.6

56− ! peek-park

57− ! exit

docs/system/hoon/runes/bc/bcpm.mddeleted−30

@@ -1,30 +0,0 @@

1−`$& bucpam`

2−===========

3−

4−Union of two cells: one w/cellular head & other w/atomic head.

5−

6−Produces a [mold]() that's a union between two different kinds of noun: a cell whose head is a cell (`p`), and cell whose head is an atom (`q`). Its default value ([bunt]()) is the value of `q`. One important use of `$&` is to implement autocons in [`++twig`]().

7−

8−Produces

9−--------

10−

11−A validator function that uses mold `p` to validate cells whose head is a cell, and `q` to validate cells whose head is an atom. Default value is the bunt of `q`.

12−

13−Accepts

14−-------

15−

16−A mold of a cell whose head is a cell `p` and a mold of a cell whose head is an atom `q`.

17−

18−Tall form

19−---------

20−

21− $& p

22− q

23−

24−Wide form

25−---------

26−

27− $&(p q)

28−

29−Examples

30−--------

docs/system/hoon/runes/bc/bctr.mddeleted−41

@@ -1,41 +0,0 @@

1−`$* buctar`

2−===========

3−

4−Bunt (default value).

5−

6−Produces the default value ([bunt]()) of [mold]() `p`. Does so as a compile-time constant if possible. If not possible, then it is produced dynamically.

7−

8−Produces

9−--------

10−

11−The default value (bunt) of the mold `p`.

12−

13−Accepts

14−-------

15−

16−A mold `p`.

17−

18−Tall form

19−---------

20−

21− $* p

22−

23−Wide form

24−---------

25−

26− $*(p)

27−

28−Irregular form

29−--------------

30−

31− *p

32−

33−Examples

34−--------

35−

36− ~zod/try=> *@t

37− ''

38− ~zod/try=> *[@p @ux]

39− [~zod 0x0]

40− ~zod/try=> *(list ,@)

41− ~

docs/system/hoon/runes/bc/bcts.mddeleted−59

@@ -1,59 +0,0 @@

1−`$= buctis`

2−===========

3−

4−Add variable name.

5−

6−Wraps a [++face]() around another [mold](). Used primarily to add variable names to values.

7−

8−Produces

9−--------

10−

11−Produces a [mold]() that validates the input value with `q`, before adding face `p`.

12−

13−Accepts

14−------

15−

16−`p` is a [++term]().

17−

18−`q` is a mold.

19−

20−Tall form

21−---------

22−

23− $= p

24− q

25−

26−Wide form

27−---------

28−

29− $=(p q)

30−

31−Irregular form

32−--------------

33−

34− `p=q`

35−note: this is only the case when in mold syntax

36−

37−Examples

38−--------

39−

40−`a=*` parses as `[%bark %a %noun]`.

41−

42− ~zod/try=> *$=(a @)

43− a=0

44− ~zod/try=> :type; *$=(a @)

45− a=0

46− a=@

47− ~zod/try=> :type; *a=@

48− a=0

49− a=@

50− ~zod/try=> :type; *a=[1 2]

51− a=[%1 %2]

52− a=[%1 %2]

53−

54− |_ [hid=bowl vat=axle]

55− ...

56− --

57−See here how we wrap the faces 'hid' and 'vat' around the two [sample]() (input) types of the core above. We can now refer to our 'bowl' and 'vat' by these names.

58−

59−

docs/system/hoon/runes/bc/bcwt.mddeleted−42

@@ -1,42 +0,0 @@

1−`$? bucwut`

2−===========

3−

4−Union of types.

5−

6−Produce a union between a non-empty list of [mold]()s `p`. The default value ([bunt]()) is the value of the first element.

7−

8−Produces

9−--------

10−

11−A validator function that keeps trying to validate a value using every mold in `p` from left to right. On a success, the value is produced. If no mold in `p` succeeds, the default value of the last element in `p` is produced.

12−

13−Accepts

14−-------

15−

16−`p` is a [++list]() of mold.

17−

18−Tall form

19−---------

20−

21− $? p

22− q

23− ==

24−

25−Irregular form

26−--------------

27−

28− ?(p q)

29−

30−Examples

31−--------

32−

33− ++ base ?([%atom p=odor] %noun %cell %bean %null) :: axils, @ * ^ ? ~

34−

35−`++base`, `?` (the irregular form of `$?`) specifies a list of

36−orthoganal cases for the `%axil` mold.

37−

38− ~zod/try=> *?(%a %b %c)

39− %a

40− ~zod/try=> :type; *?(%a %b %c)

41− %a

42− {%a %b %c}

docs/system/hoon/runes/bc/book.mdnew file+21

@@ -0,0 +1,21 @@

1+# `:book`, `$%`, "buctis", `{$book p/(list moss)}`

2+

3+The product: a mold producing the tagged union of the molds in

4+`p`, all of which must be of the form `:bank(stem bulb)`, where

5+`stem` is an atomic mold.

6+

7+Usage: define a type which is a tagged union.

8+

9+Regular form: *running*.

10+

11+Examples:

12+

13+```

14+~zod:dojo> =a :book({$foo p/@ud q/@ud} {$bar p/@ud})

15+

16+~zod:dojo> (a [%bar 37])

17+[%bar p=37]

18+

19+~zod:dojo> $:a

20+[%foo p=0 q=0]~

21+```

docs/system/hoon/runes/bc/bush.mdnew file+25

@@ -0,0 +1,25 @@

1+# `:bush`, `$&`, "bucpam", `{$bush p/moss q/moss}`

2+

3+The product: a mold which applies `p` if the head of its sample

4+is a cell, `q` if the head of its sample is a cell.

5+

6+Usage: add a default pair behavior (like "autocons" in Nock

7+formulas) to a tagged union type.

8+

9+Regular form: *2-fixed*.

10+

11+Example:

12+```

13+~zod:dojo> =a :book({$foo p/@ud q/@ud} {$bar p/@ud})

14+

15+~zod:dojo> =b :bush({a a} a)

16+

17+~zod:dojo> (b [[%bar 33] [%foo 19 22]])

18+[[%bar p=33] [%foo p=19 q=22]]

19+

20+~zod:dojo> (b [%foo 19 22])

21+[%foo p=19 q=22]

22+

23+~zod:dojo> $:b

24+[%bar p=0]

25+```

docs/system/hoon/runes/bc/claw.mdnew file+22

@@ -0,0 +1,22 @@

1+# `:claw`, `$@`, "bucpat", `{$claw p/moss q/moss}`

2+

3+The product: a mold which applies `p` if its sample is an atom,

4+`q` if its sample is a cell.

5+

6+Usage: define a type which is either an atom or a cell.

7+

8+Regular form: *2-fixed*.

9+

10+Example:

11+```

12+~zod:dojo> =a :claw($foo :bank(p/$bar q/@ud))

13+

14+~zod:dojo> (a %foo)

15+%foo

16+

17+~zod:dojo> `a`[%bar 99]

18+[p=%bar q=99]

19+

20+~zod:dojo> $:a

21+[%foo p=0 q=0]

22+```

docs/system/hoon/runes/bc/coat.mdnew file+21

@@ -0,0 +1,21 @@

1+# `:coat`, `$=`, "buctis", `{$coat p/@tas q/moss}

2+

3+The product: a mold which puts the label `p` on the mold `q`.

4+

5+Usage: name a typed attribute or variable.

6+

7+Regular form: *2-fixed*.

8+

9+Irregular form:

10+```

11+a/b :coat(a b)

12+```

13+

14+Examples:

15+

16+```

17+~zod:dojo> =a :coat(p $foo)

18+

19+~zod:dojo> (a %bar)

20+p=%foo

21+```

docs/system/hoon/runes/bc/lamb.mdnew file+15

@@ -0,0 +1,15 @@

1+# `:lamb`, `$-`, "buchep", `{$lamb p/moss q/moss}`

2+

3+The product: a mold producing a gate accepting

4+

5+Usage: define a function type.

6+

7+Regular form: *2-fixed*.

8+

9+Example:

10+```

11+~zod:dojo> =a :lamb($foo $bar)

12+

13+~zod:dojo> ($:a %foo)

14+%bar

15+```

docs/system/hoon/runes/bc/pick.mdnew file+22

@@ -0,0 +1,22 @@

1+# `:pick`, `$?`, "bucwut", `{$? p/(list moss)}`

2+

3+The product: a mold which tries each of the alternatives in `p`.

4+

5+Usage: a generalized type union. Use `:pick` only if none of

6+`:book` (`$%`), `:claw` (`$@`) or `:bush` (`$&`) applies.

7+

8+Regular form: *running*.

9+

10+Example:

11+```

12+~zod:dojo> =a :pick($foo $bar $baz)

13+

14+~zod:dojo> (a %baz)

15+%baz

16+

17+~zod:dojo> (a [37 45])

18+%foo

19+

20+~zod:dojo> $:a

21+$foo

22+```

docs/system/hoon/runes/bc/shoe.mdnew file+26

@@ -0,0 +1,26 @@

1+# `:shoe`, `$_`, "buccab", `{$shoe p/twig}`

2+

3+The product: a mold whose product is always `p`.

4+

5+Usage: define a type as a single example.

6+

7+Regular form: *1-fixed*.

8+

9+Irregular form:

10+```

11+_%foo :shoe(%foo)

12+```

13+

14+Example:

15+```

16+~zod:dojo> =a :shoe([%foobar %moobaz])

17+

18+~zod:dojo> (a %foo %bar)

19+[%foobar %moobaz]

20+

21+~zod:dojo> `a`[%foobar %moobaz]

22+[%foobar %moobaz]

23+

24+~zod:dojo $:a

25+[%foobar %moobaz]

26+```