helins.void
Macros and functions for handling nil under various circumstances.
Macros and functions for handling nil under various circumstances.
altclj/smacro
(alt)(alt x)(alt x & xs)Selects the first non-nil value.
Being a macro, arguments are not evaluated until needed.
(= (alt nil false 42)
false)
;; Different from `or`
;;
(= (or nil false 42)
42)
Selects the first non-nil value. Being a macro, arguments are not evaluated until needed. ```clojure (= (alt nil false 42) false) ;; Different from `or` ;; (= (or nil false 42) 42) ```
assocclj/s
(assoc hmap k v)(assoc hmap k v & kvs)Behaves like standard assoc but associates v only if it is not nil.
(= (assoc {:a 42}
:a nil
:b 42)
{:a 42
:b 42})
Behaves like standard `assoc` but associates `v` only if it is not nil.
```clojure
(= (assoc {:a 42}
:a nil
:b 42)
{:a 42
:b 42})
```assoc-inclj/s
(assoc-in hmap path v)Behaves like standard assoc-in but associates v only if it is not nil.
See also assoc.
Behaves like standard `assoc-in` but associates `v` only if it is not nil. See also [[assoc]].
assoc-strictclj/s
(assoc-strict hmap k v)(assoc-strict hmap k v & kvs)Similar to this namespace's version of assoc but if v is nil, not only is it not associated, the
involved key is actually removed from the map.
Similar to this namespace's version of [[assoc]] but if `v` is nil, not only is it not associated, the involved key is actually removed from the map.
callclj/smacro
(call f & args)Calls f with the given arguments only if f is not nil.
Being a macro, the arguments are not evaluated until they are needed.
Calls `f` with the given arguments only if `f` is not nil. Being a macro, the arguments are not evaluated until they are needed.
dissoc-inclj/s
(dissoc-in hmap path)Deep dissoc, natural counterpart of Clojure's assoc-in.
It is recursive, meaning that if dissociating a key results in an empty map, this map itself is removed from its parent (provided it is of course nested).
(= (dissoc-in {:a {:b {:c {:d 42}}
:e 42}}
[:a :b :c :d])
{:a {:e 42}})
Deep dissoc, natural counterpart of Clojure's `assoc-in`.
It is recursive, meaning that if dissociating a key results in an empty map, this map itself is removed from its
parent (provided it is of course nested).
```clojure
(= (dissoc-in {:a {:b {:c {:d 42}}
:e 42}}
[:a :b :c :d])
{:a {:e 42}})
```dmergeclj/s
(dmerge & hmaps)Deep merges the given maps.
Merging a key pointing to nil results in that key being dissociated. Similarly to dissoc-in, empty maps are recursively
removed.
(= (dmerge {:a {:b {:c {:d 42}}
:e 42}}
{:a {:b {:c {:d nil}}
:f 42}})
{:a {:e 42
:f 42}})
Deep merges the given maps.
Merging a key pointing to nil results in that key being dissociated. Similarly to [[dissoc-in]], empty maps are recursively
removed.
```clojure
(= (dmerge {:a {:b {:c {:d 42}}
:e 42}}
{:a {:b {:c {:d nil}}
:f 42}})
{:a {:e 42
:f 42}})
```dmerge-withclj/s
(dmerge-with f & hmaps)Is to dmerge what this namespace's version of merge-with is to merge.
Is to [[dmerge]] what this namespace's version of [[merge-with]] is to [[merge]].
dmerge-with*clj/s
(dmerge-with* f hmaps)(dmerge-with* f hmap-1 hmap-2)Like dmerge-with, but maps are provided in a collection.
Like [[dmerge-with]], but maps are provided in a collection.
mergeclj/s
(merge & hmaps)Just like standard merge, but a key pointing to nil in the right map means it must be dissociated.
(= (merge {:a 42
:b 42}
{:b nil
:c 42})
{:a 42
:c 42})
Just like standard `merge`, but a key pointing to nil in the right map means it must be dissociated.
```clojure
(= (merge {:a 42
:b 42}
{:b nil
:c 42})
{:a 42
:c 42})
```merge-withclj/s
(merge-with f & hmaps)Just like standard 'merge-with' but behaves like this namespace's version of merge: a key pointing to a nil value in a
right map means it will be dissociated. The same applies when f returns nil.
Just like standard 'merge-with' but behaves like this namespace's version of [[merge]]: a key pointing to a nil value in a right map means it will be dissociated. The same applies when `f` returns nil.
merge-with*clj/s
(merge-with* f hmaps)Just like this namespace's version of merge-with but maps are provided in a collection.
Just like this namespace's version of [[merge-with]] but maps are provided in a collection.
no-opclj/s
(no-op)(no-op _)(no-op _ _)(no-op _ _ _)(no-op _ _ _ _)(no-op _ _ _ _ _)(no-op _ _ _ _ _ _)(no-op _ _ _ _ _ _ _)(no-op _ _ _ _ _ _ _ _)(no-op _ _ _ _ _ _ _ _ & _)Does absolutely nothing, but efficiently.
Does absolutely nothing, but efficiently.
pruneclj/s
(prune node)If node is a map, keys with nil values will be removed. In case of nested maps, the process is recursive.
(= (prune {:a 42
:b {:c 42
:d nil
:e {:f {:g nil}}}})
{:a 42
:b {:c 42}})
(= (prune 42)
42)
If node is a map, keys with nil values will be removed. In case of nested maps, the process is recursive.
```clojure
(= (prune {:a 42
:b {:c 42
:d nil
:e {:f {:g nil}}}})
{:a 42
:b {:c 42}})
(= (prune 42)
42)
```updateclj/s
(update hmap k f)(update hmap k f a)(update hmap k f a b)(update hmap k f a b c)(update hmap k f a b c & more)Just like standard update but returning a nil value results in the involved key being dissociated.
(= (update {:a 42
:b 42}
:b
(fn [x]
nil))
{:a 42})Just like standard `update` but returning a nil value results in the involved key being dissociated.
```clojure
(= (update {:a 42
:b 42}
:b
(fn [x]
nil))
{:a 42})update-inclj/s
(update-in hmap path f & args)Just like standard update-in but like this namespace's version of update, returning nil
results in the involved key being dissociated.
Similarly to dissoc-in, empty maps are then recursively removed as well.
When an empty path is provided, nothing happens.
(= (update-in {:a {:b {:c {:d 24}}
:e 42}}
[:a :b :c :d]
(fn [x]
(when (= x
42)
x)))
{:a {:e 42}})
Just like standard `update-in` but like this namespace's version of [[update]], returning nil
results in the involved key being dissociated.
Similarly to [[dissoc-in]], empty maps are then recursively removed as well.
When an empty path is provided, nothing happens.
```clojure
(= (update-in {:a {:b {:c {:d 24}}
:e 42}}
[:a :b :c :d]
(fn [x]
(when (= x
42)
x)))
{:a {:e 42}})
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