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Minor edits and add subselect example.

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Christopher O'Donnell 2016-06-11 21:56:45 -04:00
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1 changed files with 27 additions and 17 deletions
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List-of-Navigators.md
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@ -19,7 +19,7 @@
### ALL ### ALL
`ALL` navigates to every element in a collection. If the collection is a map, it will navigate to each key-value pair `[key value]`. `ALL` navigates to every element in a collection. If the collection is a map, it will navigate to each key-value pair `[key value]`. Reconstructs collection items as a vector when used in a select.
```clojure ```clojure
=> (select ALL [0 1 2 3]) => (select ALL [0 1 2 3])
@ -47,7 +47,7 @@
### BEGINNING ### BEGINNING
`BEGINNING` navigates to the empty subsequence before the beginning of a collection. Useful with `setval` to add values onto the beginning of a sequence. Returns a lazy sequence. `BEGINNING` navigates to the empty subsequence before the beginning of a collection. Useful with `setval` to add values onto the beginning of a sequence. Returns a lazy sequence when used in a select.
```clojure ```clojure
=> (setval BEGINNING '(0 1) (range 2 7)) => (setval BEGINNING '(0 1) (range 2 7))
@ -111,7 +111,7 @@ nil
### MAP-VALS ### MAP-VALS
`MAP-VALS` navigates to every value in a map. `MAP-VALS` is more efficient than `[ALL LAST]`. Note that `MAP-VALS` returns a lazy seq. `MAP-VALS` navigates to every value in a map. `MAP-VALS` is more efficient than `[ALL LAST]`. Returns a lazy seq when used in a select.
```clojure ```clojure
=> (select MAP-VALS {:a :b, :c :d}) => (select MAP-VALS {:a :b, :c :d})
@ -164,7 +164,7 @@ nil
### STOP ### STOP
`STOP` stops navigation. For selection, returns nil. For transformation, returns the structure unchanged. `STOP` stops navigation. For transformation, returns the structure unchanged.
```clojure ```clojure
=> (select-one STOP :foo) => (select-one STOP :foo)
@ -198,7 +198,7 @@ See also [collect](#collect), [collect-one](#collect-one), and [putval](#putval)
Using clojure.walk, `codewalker` executes a depth-first search for nodes where `afn` Using clojure.walk, `codewalker` executes a depth-first search for nodes where `afn`
returns a truthy value. When `afn` returns a truthy value, `codewalker` stops returns a truthy value. When `afn` returns a truthy value, `codewalker` stops
searching that branch of the tree and continues its search of the rest of the searching that branch of the tree and continues its search of the rest of the
data structure. `codewalker` preserves the metadata of any forms traversed. data structure. `codewalker` preserves the metadata of any forms traversed. Returns a lazy seq when used in a select.
See also [walker](#walker). See also [walker](#walker).
@ -214,7 +214,7 @@ See also [walker](#walker).
`(collect & paths)` `(collect & paths)`
`collect` adds the result of running `collect` with the given path on the current value to the collected vals. Note that `collect`, like `select`, returns a vector containing its results. If `transform` is called, each collected value will be passed in as an argument to the transforming function, with the resulting value as the last argument. `collect` adds the result of running `collect` with the given path on the current value to the collected vals. Note that `collect`, like `select`, returns a vector containing its results. If `transform` is called, each collected value will be passed as an argument to the transforming function with the resulting value as the last argument.
See also [VAL](#val), [collect-one](#collect-one), and [putval](#putval) See also [VAL](#val), [collect-one](#collect-one), and [putval](#putval)
@ -239,7 +239,7 @@ See also [VAL](#val), [collect-one](#collect-one), and [putval](#putval)
`(collect-one & paths)` `(collect-one & paths)`
`collect-one` adds the result of running `collect` with the given path on the current value to the collected vals. Note that `collect-one`, like `select-one`, returns a single result. If there is more than one result, an exception will be thrown. If `transform` is called, each collected value will be passed in as an argument to the transforming function, with the resulting value as the last argument. `collect-one` adds the result of running `collect` with the given path on the current value to the collected vals. Note that `collect-one`, like `select-one`, returns a single result. If there is more than one result, an exception will be thrown. If `transform` is called, each collected value will be passed as an argument to the transforming function with the resulting value as the last argument.
See also [VAL](#val), [collect](#collect), and [putval](#putval) See also [VAL](#val), [collect](#collect), and [putval](#putval)
@ -305,7 +305,7 @@ See also [if-path](#if-path)
`(continue-then-stay & path)` `(continue-then-stay & path)`
Navigates to the provided path and then to the current element. This can be used Navigates to the provided path and then to the current element. This can be used
to implement post-order traversal. to implement post-order traversal. Returns a lazy seq when used in a select.
See also [stay-then-continue](#stay-then-continue). See also [stay-then-continue](#stay-then-continue).
@ -318,13 +318,15 @@ See also [stay-then-continue](#stay-then-continue).
`(continuous-subseqs pred)` `(continuous-subseqs pred)`
Navigates to every continuous subsequence of elements matching `pred`. Navigates to every continuous subsequence of elements matching `pred`. Returns a lazy seq when used in a select.
```clojure ```clojure
=> (select (continuous-subseqs #(< % 10)) [5 6 11 11 3 12 2 5]) => (select (continuous-subseqs #(< % 10)) [5 6 11 11 3 12 2 5])
([5 6] [3] [2 5]) ([5 6] [3] [2 5])
=> (select (continuous-subseqs #(< % 10)) [12 13]) => (select (continuous-subseqs #(< % 10)) [12 13])
() ()
=> (setval (continuous-subseqs #(< % 10)) [] [3 2 5 11 12 5 20])
[11 12 20]
``` ```
### filterer ### filterer
@ -333,12 +335,14 @@ Navigates to every continuous subsequence of elements matching `pred`.
Navigates to a view of the current sequence that only contains elements that Navigates to a view of the current sequence that only contains elements that
match the given path. An element matches the selector path if calling select match the given path. An element matches the selector path if calling select
on that element with the path yields anything other than an empty sequence. on that element with the path yields anything other than an empty sequence. Returns a vector when used in a select.
The input path may be parameterized, in which case the result of filterer The input path may be parameterized, in which case the result of filterer
will be parameterized in the order of which the parameterized selectors will be parameterized in the order of which the parameterized selectors
were declared. Note that filterer is a function which returns a navigator. It is the arguments to filterer that can be parametrized, not filterer. were declared. Note that filterer is a function which returns a navigator. It is the arguments to filterer that can be parametrized, not filterer.
See also [subselect](#subselect).
```clojure ```clojure
;; Note that clojure functions have been extended to implement the navigator protocol ;; Note that clojure functions have been extended to implement the navigator protocol
=> (select-one (filterer even?) (range 10)) => (select-one (filterer even?) (range 10))
@ -554,15 +558,17 @@ nil
`(srange start end)` `(srange start end)`
Navigates to the subsequence bound by the indexes start (inclusive) Navigates to the subsequence bound by the indexes start (inclusive)
and end (exclusive). and end (exclusive). Returns a vector when used in a select.
See also [srange-dynamic](#srange-dynamic). See also [srange-dynamic](#srange-dynamic) and [subselect](#subselect).
```clojure ```clojure
=> (select-one (srange 2 4) (range 5)) => (select-one (srange 2 4) (range 5))
[2 3] [2 3]
=> (select-one (srange 0 10) (range 5)) => (select-one (srange 0 10) (range 5))
IndexOutOfBoundsException IndexOutOfBoundsException
=> (setval (srange 2 4) [] (range 5))
(0 1 4)
``` ```
### srange-dynamic ### srange-dynamic
@ -570,7 +576,7 @@ IndexOutOfBoundsException
`(srange-dynamic start-fn end-fn)` `(srange-dynamic start-fn end-fn)`
Uses start-fn and end-fn to determine the bounds of the subsequence Uses start-fn and end-fn to determine the bounds of the subsequence
to select when navigating. Each function takes in the structure as input. to select when navigating. Each function takes in the structure as input. Returns a vector when used in a select.
See also [srange](#srange). See also [srange](#srange).
@ -625,16 +631,20 @@ value of the submap.
Navigates to a sequence that contains the results of (select ...), Navigates to a sequence that contains the results of (select ...),
but is a view to the original structure that can be transformed. but is a view to the original structure that can be transformed.
Without subselect, we could only transform selected values individually.
`subselect` lets us transform them together as a seq, much like `filterer`.
Requires that the input navigators will walk the structure's Requires that the input navigators will walk the structure's
children in the same order when executed on "select" and then children in the same order when executed on "select" and then
"transform". "transform".
I don't know what this one is good for yet. The below example could easily be written with just transformed. See also [srange](#srange) and [filterer](#filterer).
```clojure ```clojure
=> (select-one [(subselect ALL (transformed STAY inc)) FIRST] (range 5)) => (transform (subselect (walker number?) even?)
1 reverse
[1 [[[2]] 3] 5 [6 [7 8]] 10])
[1 [[[10]] 3] 5 [8 [7 6]] 2]
``` ```
### subset ### subset
@ -694,7 +704,7 @@ See also [transformed](#transformed).
Using clojure.walk, `walker` executes a depth-first search for nodes where `afn` Using clojure.walk, `walker` executes a depth-first search for nodes where `afn`
returns a truthy value. When `afn` returns a truthy value, `walker` stops returns a truthy value. When `afn` returns a truthy value, `walker` stops
searching that branch of the tree and continues its search of the rest of the searching that branch of the tree and continues its search of the rest of the
data structure. data structure. Returns a lazy seq when used in a select.
See also [codewalker](#codewalker) See also [codewalker](#codewalker)