mediocre-blog/assets/viz/2/clojure/string.cljs
2018-11-12 16:18:45 -05:00

259 lines
7.0 KiB
Clojure

; Copyright (c) Rich Hickey. All rights reserved.
; The use and distribution terms for this software are covered by the
; Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
; which can be found in the file epl-v10.html at the root of this distribution.
; By using this software in any fashion, you are agreeing to be bound by
; the terms of this license.
; You must not remove this notice, or any other, from this software.
(ns clojure.string
(:refer-clojure :exclude [replace reverse])
(:require [goog.string :as gstring])
(:import [goog.string StringBuffer]))
(defn- seq-reverse
[coll]
(reduce conj () coll))
(def ^:private re-surrogate-pair
(js/RegExp. "([\\uD800-\\uDBFF])([\\uDC00-\\uDFFF])" "g"))
(defn reverse
"Returns s with its characters reversed."
[s]
(-> (.replace s re-surrogate-pair "$2$1")
(.. (split "") (reverse) (join ""))))
(defn- replace-all
[s re replacement]
(.replace s (js/RegExp. (.-source re) "g") replacement))
(defn- replace-with
[f]
(fn [& args]
(let [matches (drop-last 2 args)]
(if (= (count matches) 1)
(f (first matches))
(f (vec matches))))))
(defn replace
"Replaces all instance of match with replacement in s.
match/replacement can be:
string / string
pattern / (string or function of match)."
[s match replacement]
(cond
(string? match)
(.replace s (js/RegExp. (gstring/regExpEscape match) "g") replacement)
(instance? js/RegExp match)
(if (string? replacement)
(replace-all s match replacement)
(replace-all s match (replace-with replacement)))
:else (throw (str "Invalid match arg: " match))))
(defn replace-first
"Replaces the first instance of match with replacement in s.
match/replacement can be:
string / string
pattern / (string or function of match)."
[s match replacement]
(.replace s match replacement))
(defn join
"Returns a string of all elements in coll, as returned by (seq coll),
separated by an optional separator."
([coll]
(loop [sb (StringBuffer.) coll (seq coll)]
(if-not (nil? coll)
(recur (. sb (append (str (first coll)))) (next coll))
(.toString sb))))
([separator coll]
(loop [sb (StringBuffer.) coll (seq coll)]
(if-not (nil? coll)
(do
(. sb (append (str (first coll))))
(let [coll (next coll)]
(when-not (nil? coll)
(. sb (append separator)))
(recur sb coll)))
(.toString sb)))))
(defn upper-case
"Converts string to all upper-case."
[s]
(.toUpperCase s))
(defn lower-case
"Converts string to all lower-case."
[s]
(.toLowerCase s))
(defn capitalize
"Converts first character of the string to upper-case, all other
characters to lower-case."
[s]
(if (< (count s) 2)
(upper-case s)
(str (upper-case (subs s 0 1))
(lower-case (subs s 1)))))
;; The JavaScript split function takes a limit argument but the return
;; value is not the same as the Java split function.
;;
;; Java: (.split "a-b-c" #"-" 2) => ["a" "b-c"]
;; JavaScript: (.split "a-b-c" #"-" 2) => ["a" "b"]
;;
;; For consistency, the three arg version has been implemented to
;; mimic Java's behavior.
(defn- pop-last-while-empty
[v]
(loop [v v]
(if (identical? "" (peek v))
(recur (pop v))
v)))
(defn- discard-trailing-if-needed
[limit v]
(if (and (== 0 limit) (< 1 (count v)))
(pop-last-while-empty v)
v))
(defn- split-with-empty-regex
[s limit]
(if (or (<= limit 0) (>= limit (+ 2 (count s))))
(conj (vec (cons "" (map str (seq s)))) "")
(condp == limit
1 (vector s)
2 (vector "" s)
(let [c (- limit 2)]
(conj (vec (cons "" (subvec (vec (map str (seq s))) 0 c))) (subs s c))))))
(defn split
"Splits string on a regular expression. Optional argument limit is
the maximum number of splits. Not lazy. Returns vector of the splits."
([s re]
(split s re 0))
([s re limit]
(discard-trailing-if-needed limit
(if (identical? "/(?:)/" (str re))
(split-with-empty-regex s limit)
(if (< limit 1)
(vec (.split (str s) re))
(loop [s s
limit limit
parts []]
(if (== 1 limit)
(conj parts s)
(let [m (re-find re s)]
(if-not (nil? m)
(let [index (.indexOf s m)]
(recur (.substring s (+ index (count m)))
(dec limit)
(conj parts (.substring s 0 index))))
(conj parts s))))))))))
(defn split-lines
"Splits s on \n or \r\n."
[s]
(split s #"\n|\r\n"))
(defn trim
"Removes whitespace from both ends of string."
[s]
(gstring/trim s))
(defn triml
"Removes whitespace from the left side of string."
[s]
(gstring/trimLeft s))
(defn trimr
"Removes whitespace from the right side of string."
[s]
(gstring/trimRight s))
(defn trim-newline
"Removes all trailing newline \\n or return \\r characters from
string. Similar to Perl's chomp."
[s]
(loop [index (.-length s)]
(if (zero? index)
""
(let [ch (get s (dec index))]
(if (or (identical? \newline ch)
(identical? \return ch))
(recur (dec index))
(.substring s 0 index))))))
(defn ^boolean blank?
"True is s is nil, empty, or contains only whitespace."
[s]
(gstring/isEmptySafe s))
(defn escape
"Return a new string, using cmap to escape each character ch
from s as follows:
If (cmap ch) is nil, append ch to the new string.
If (cmap ch) is non-nil, append (str (cmap ch)) instead."
[s cmap]
(let [buffer (StringBuffer.)
length (.-length s)]
(loop [index 0]
(if (== length index)
(. buffer (toString))
(let [ch (.charAt s index)
replacement (get cmap ch)]
(if-not (nil? replacement)
(.append buffer (str replacement))
(.append buffer ch))
(recur (inc index)))))))
(defn index-of
"Return index of value (string or char) in s, optionally searching
forward from from-index or nil if not found."
([s value]
(let [result (.indexOf s value)]
(if (neg? result)
nil
result)))
([s value from-index]
(let [result (.indexOf s value from-index)]
(if (neg? result)
nil
result))))
(defn last-index-of
"Return last index of value (string or char) in s, optionally
searching backward from from-index or nil if not found."
([s value]
(let [result (.lastIndexOf s value)]
(if (neg? result)
nil
result)))
([s value from-index]
(let [result (.lastIndexOf s value from-index)]
(if (neg? result)
nil
result))))
(defn ^boolean starts-with?
"True if s starts with substr."
[s substr]
(gstring/startsWith s substr))
(defn ^boolean ends-with?
"True if s ends with substr."
[s substr]
(gstring/endsWith s substr))
(defn ^boolean includes?
"True if s includes substr."
[s substr]
(gstring/contains s substr))