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Merge pull request #1578 from sogaiu/tweak-some-docstrings

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Tweak doc for mapcat, count, keep, all, some
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Calvin Rose 2025-04-04 21:45:09 -05:00 committed by GitHub
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1 changed files with 46 additions and 13 deletions
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src/boot/boot.janet
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@ -1098,8 +1098,14 @@
res)
(defn mapcat
``Map a function over every element in an array or tuple and
use `array/concat` to concatenate the results.``
```
Map a function `f` over every value in a data structure `ind`
and use `array/concat` to concatenate the results, but only if
no `inds` are provided. Multiple data structures can be handled
if each `inds` is a data structure and `f` is a function of
arity one more than the number of `inds`. The resulting array
has a length that is the shortest of `ind` and each of `inds`.
```
[f ind & inds]
(def res @[])
(map-template :mapcat res f ind inds)
@ -1116,18 +1122,30 @@
res)
(defn count
``Count the number of items in `ind` for which `(pred item)`
is true.``
```
Count the number of values in a data structure `ind` for which
applying `pred` yields a truthy value, but only if no `inds` are
provided. Multiple data structures can be handled if each `inds`
is a data structure and `pred` is a function of arity one more
than the number of `inds`. Note that `pred` is only applied to
values at indeces up to the largest index of the shortest of
`ind` and each of `inds`.
```
[pred ind & inds]
(var res 0)
(map-template :count res pred ind inds)
res)
(defn keep
``Given a predicate `pred`, return a new array containing the truthy results
of applying `pred` to each element in the indexed collection `ind`. This is
different from `filter` which returns an array of the original elements where
the predicate is truthy.``
```
Given a predicate `pred`, return a new array containing the
truthy results of applying `pred` to each value in the data
structure `ind`, but only if no `inds` are provided. Multiple
data structures can be handled if each `inds` is a data
structure and `pred` is a function of arity one more than the
number of `inds`. The resulting array has a length that is the
shortest of `ind` and each of `inds`.
```
[pred ind & inds]
(def res @[])
(map-template :keep res pred ind inds)
@ -2209,17 +2227,32 @@
ret)
(defn all
``Returns true if `(pred item)` is truthy for every item in `ind`.
Otherwise, returns the first falsey result encountered.
Returns true if `ind` is empty.``
```
Returns true if applying `pred` to every value in a data
structure `ind` results in only truthy values, but only if no
`inds` are provided. Multiple data structures can be handled
if each `inds` is a data structure and `pred` is a function
of arity one more than the number of `inds`. Returns the first
falsey result encountered. Note that `pred` is only called as
many times as the length of the shortest of `ind` and each of
`inds`. If `ind` or any of `inds` are empty, returns true.
```
[pred ind & inds]
(var res true)
(map-template :all res pred ind inds)
res)
(defn some
``Returns nil if `(pred item)` is false or nil for every item in `ind`.
Otherwise, returns the first truthy result encountered.``
```
Returns nil if applying `pred` to every value in a data
structure `ind` results in only falsey values, but only if no
`inds` are provided. Multiple data structures can be handled
if each `inds` is a data structure and `pred` is a function
of arity one more than the number of `inds`. Returns the first
truthy result encountered. Note that `pred` is only called as
many times as the length of the shortest of `ind` and each of
`inds`. If `ind` or any of `inds` are empty, returns nil.
```
[pred ind & inds]
(var res nil)
(map-template :some res pred ind inds)