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0.16.0: 2-arg x/str is now a string-producing transducing context. Adds x/wrap.

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Also change documentation to use the term aggregator for 1-item-out transducers.
This commit is contained in:
Christophe Grand 2018-01-25 10:41:36 +01:00
parent db0555c358
commit 7c048e11bb
4 changed files with 37 additions and 10 deletions
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14
README.md
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@ -5,14 +5,14 @@ More transducers and reducing functions for Clojure(script)!
[![Build Status](https://travis-ci.org/cgrand/xforms.png?branch=master)](https://travis-ci.org/cgrand/xforms)
*Transducers* can be classified in three groups: regular ones, higher-order ones
(which accept other transducers as arguments) and 1-item ones which emit only 1 item out no matter how many went in.
1-item transducers generally only make sense in the context of a higher-order transducer.
(which accept other transducers as arguments) and aggrerators (transdcuers which emit only 1 item out no matter how many went in).
Aggregators generally only make sense in the context of a higher-order transducer.
In `net.cgrand.xforms`:
* regular ones: `partition` (1 arg), `reductions`, `for`, `take-last`, `drop-last`, `sort`, `sort-by`, `window` and `window-by-time`
* regular ones: `partition` (1 arg), `reductions`, `for`, `take-last`, `drop-last`, `sort`, `sort-by`, `wrap`, `window` and `window-by-time`
* higher-order ones: `by-key`, `into-by-key`, `multiplex`, `transjuxt`, `partition` (2+ args)
* 1-item ones: `reduce`, `into`, `without`, `transjuxt`, `last`, `count`, `avg`, `sd`, `min`, `minimum`, `max`, `maximum`, `str`
* aggregators: `reduce`, `into`, `without`, `transjuxt`, `last`, `count`, `avg`, `sd`, `min`, `minimum`, `max`, `maximum`, `str`
In `net.cgrand.xforms.io`:
* `sh` to use any process as a transducer
@ -27,7 +27,7 @@ In `net.cgrand.xforms.io`:
*Transducing contexts*:
* in `net.cgrand.xforms`: `transjuxt` (for performing several transductions in a single pass), `iterator` (clojure only), `into`, `without`, `count` and `some`.
* in `net.cgrand.xforms`: `transjuxt` (for performing several transductions in a single pass), `iterator` (clojure only), `into`, `without`, `count`, `str` (2 args) and `some`.
* in `net.cgrand.xforms.io`: `line-out` (3+ args) and `edn-out` (3+ args).
* in `net.cgrand.xforms.nodejs.stream`: `transformer`.
@ -40,7 +40,7 @@ In `net.cgrand.xforms.io`:
Add this dependency to your project:
```clj
[net.cgrand/xforms "0.15.0"]
[net.cgrand/xforms "0.16.0"]
```
```clj
@ -151,7 +151,7 @@ It's worth noting that all transformed outputs are subsequently interleaved. See
([false 0] [true 1] [false 2] [true 3] [false 4] [true 5] [false 6] [true 7])
```
That's why most of the time the last stage of the sub-transducer will be a 1-item transducer like `x/reduce` or `x/into`:
That's why most of the time the last stage of the sub-transducer will be an aggregator like `x/reduce` or `x/into`:
```clj
=> (sequence (x/partition 2 1 (x/into [])) (range 8))

2
package.json
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@ -1,6 +1,6 @@
{
"name": "xforms",
"version": "0.15.0",
"version": "0.16.0",
"description": "Extra transducers for Clojurescript",
"repository": "https://github.com/cgrand/xforms.git",
"author": "Christophe Grand <christophe@cgrand.net>",

2
project.clj
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@ -1,4 +1,4 @@
(defproject net.cgrand/xforms "0.15.0"
(defproject net.cgrand/xforms "0.16.0"
:description "Extra transducers for Clojure"
:url "https://github.com/cgrand/xforms"
:license {:name "Eclipse Public License"

29
src/net/cgrand/xforms.cljc
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@ -248,7 +248,34 @@
(def max (reduce rf/max))
(def str (reduce rf/str))
(defn str
"When used as a value, it's an aggregating transducer that concatenates input values
into a single output value.
When used as a function of two args (xform and coll) it's a transducing context that
concatenates all values in a string."
{:arglists '([xform coll])}
([rf] ((reduce rf/str) rf))
([xform coll]
(transduce xform rf/str coll)))
(defn wrap
"Transducer. Adds open as the first item, and close as the last. Optionally inserts delim between each input item."
([open close]
(fn [rf]
(let [vrf (volatile! nil)]
(vreset! vrf
(fn [acc x]
(let [acc (rf acc open)]
(vreset! vrf rf)
(if (reduced? acc)
acc
(rf acc x)))))
(fn
([] (rf))
([acc] (rf (unreduced (rf acc close))))
([acc x] (@vrf acc x))))))
([open close delim]
(comp (interpose delim) (wrap open close))))
(defn vals [rf]
(kvrf