X-Git-Url: https://git.ladys.computer/Pisces/blobdiff_plain/15a0a4d62a2816fc55f98064a81034ae2fc13404..fb3e0d562e2dbe9e3ea911a80bfdabc8851f92b2:/string.js?ds=inline

diff --git a/string.js b/string.js
index 17e8736..3dc39ac 100644
--- a/string.js
+++ b/string.js
@@ -7,75 +7,708 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this
 // file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
 
+import { bind, call, identity, makeCallable } from "./function.js";
+import {
+  defineOwnProperties,
+  getOwnPropertyDescriptors,
+  getPrototype,
+  objectCreate,
+  setPrototype,
+} from "./object.js";
+
+export const {
+  /**
+   * A RegExp·like object which only matches entire strings, and may
+   * have additional constraints specified.
+   *
+   * Matchers are callable objects and will return true if they are
+   * called with a string that they match, and false otherwise.
+   * Matchers will always return false if called with nonstrings,
+   * although other methods like `exec` coerce their arguments and may
+   * still return true.
+   */
+  Matcher,
+} = (() => {
+  const RE = RegExp;
+  const { prototype: rePrototype } = RE;
+  const { exec: reExec, toString: reToString } = rePrototype;
+  const getDotAll =
+    Object.getOwnPropertyDescriptor(rePrototype, "dotAll").get;
+  const getGlobal =
+    Object.getOwnPropertyDescriptor(rePrototype, "global").get;
+  const getHasIndices =
+    Object.getOwnPropertyDescriptor(rePrototype, "hasIndices").get;
+  const getIgnoreCase =
+    Object.getOwnPropertyDescriptor(rePrototype, "ignoreCase").get;
+  const getMultiline =
+    Object.getOwnPropertyDescriptor(rePrototype, "multiline").get;
+  const getSource =
+    Object.getOwnPropertyDescriptor(rePrototype, "source").get;
+  const getSticky =
+    Object.getOwnPropertyDescriptor(rePrototype, "sticky").get;
+  const getUnicode =
+    Object.getOwnPropertyDescriptor(rePrototype, "unicode").get;
+
+  const Matcher = class extends identity {
+    #constraint;
+    #regExp;
+
+    /**
+     * Constructs a new Matcher from the provided source.
+     *
+     * If the provided source is a regular expression, then it must
+     * have the unicode flag set. Otherwise, it is interpreted as the
+     * string source of a regular expression with the unicode flag set.
+     *
+     * Other flags are taken from the provided regular expression
+     * object, if any are present.
+     *
+     * A name for the matcher may be provided as the second argument.
+     *
+     * A callable constraint on acceptable inputs may be provided as a
+     * third argument. If provided, it will be called with three
+     * arguments whenever a match appears successful: first, the string
+     * being matched, second, the match result, and third, the Matcher
+     * object itself. If the return value of this call is falsey, then
+     * the match will be considered a failure.
+     *
+     * ☡ If the provided source regular expression uses nongreedy
+     * quantifiers, it may not match the whole string even if a match
+     * with the whole string is possible. Surround the regular
+     * expression with `^(?:` and `)$` if you don’t want nongreedy
+     * regular expressions to fail when shorter matches are possible.
+     */
+    constructor(source, name = undefined, constraint = null) {
+      super(
+        ($) => {
+          if (typeof $ !== "string") {
+            // The provided value is not a string.
+            return false;
+          } else {
+            // The provided value is a string. Set the `lastIndex` of
+            // the regular expression to 0 and see if the first attempt
+            // at a match matches the whole string and passes the
+            // provided constraint (if present).
+            regExp.lastIndex = 0;
+            const result = call(reExec, regExp, [$]);
+            return result?.[0] === $ &&
+              (constraint === null || constraint($, result, this));
+          }
+        },
+      );
+      const regExp = this.#regExp = (() => {
+        try {
+          call(reExec, source, [""]); // throws if source not a RegExp
+        } catch {
+          return new RE(`${source}`, "u");
+        }
+        const unicode = call(getUnicode, source, []);
+        if (!unicode) {
+          // The provided regular expression does not have a unicode
+          // flag.
+          throw new TypeError(
+            `Piscēs: Cannot create Matcher from non‐Unicode RegExp: ${source}`,
+          );
+        } else {
+          // The provided regular expression has a unicode flag.
+          return new RE(source);
+        }
+      })();
+      if (constraint !== null && typeof constraint !== "function") {
+        throw new TypeError(
+          "Piscēs: Cannot construct Matcher: Constraint is not callable.",
+        );
+      } else {
+        this.#constraint = constraint;
+        return defineOwnProperties(
+          setPrototype(this, matcherPrototype),
+          {
+            lastIndex: {
+              configurable: false,
+              enumerable: false,
+              value: 0,
+              writable: false,
+            },
+            name: {
+              value: name != null
+                ? `${name}`
+                : `Matcher(${call(reToString, regExp, [])})`,
+            },
+          },
+        );
+      }
+    }
+
+    /** Gets whether the dotAll flag is present on this Matcher. */
+    get dotAll() {
+      return call(getDotAll, this.#regExp, []);
+    }
+
+    /**
+     * Executes this Matcher on the provided value and returns the
+     * result if there is a match, or null otherwise.
+     *
+     * Matchers only match if they can match the entire value on the
+     * first attempt.
+     *
+     * ☡ The match result returned by this method will be the same as
+     * that passed to the constraint function—and may have been
+     * modified by said function prior to being returned.
+     */
+    exec($) {
+      const regExp = this.#regExp;
+      const constraint = this.#constraint;
+      const string = `${$}`;
+      regExp.lastIndex = 0;
+      const result = call(reExec, regExp, [string]);
+      if (
+        result?.[0] === string &&
+        (constraint === null || constraint(string, result, this))
+      ) {
+        // The entire string was matched and the constraint, if
+        // present, returned a truthy value.
+        return result;
+      } else {
+        // The entire string was not matched or the constraint returned
+        // a falsey value.
+        return null;
+      }
+    }
+
+    /** Gets whether the global flag is present on this Matcher. */
+    get global() {
+      return call(getGlobal, this.#regExp, []);
+    }
+
+    /** Gets whether the hasIndices flag is present on this Matcher. */
+    get hasIndices() {
+      return call(getHasIndices, this.#regExp, []);
+    }
+
+    /** Gets whether the ignoreCase flag is present on this Matcher. */
+    get ignoreCase() {
+      return call(getIgnoreCase, this.#regExp, []);
+    }
+
+    /** Gets whether the multiline flag is present on this Matcher. */
+    get multiline() {
+      return call(getMultiline, this.#regExp, []);
+    }
+
+    /** Gets the regular expression source for this Matcher. */
+    get source() {
+      return call(getSource, this.#regExp, []);
+    }
+
+    /** Gets whether the sticky flag is present on this Matcher. */
+    get sticky() {
+      return call(getSticky, this.#regExp, []);
+    }
+
+    /**
+     * Gets whether the unicode flag is present on this Matcher.
+     *
+     * ※ This will always be true.
+     */
+    get unicode() {
+      return call(getUnicode, this.#regExp, []);
+    }
+  };
+
+  const matcherConstructor = defineOwnProperties(
+    class extends RegExp {
+      constructor(...args) {
+        return new Matcher(...args);
+      }
+    },
+    {
+      name: { value: "Matcher" },
+      length: { value: 1 },
+    },
+  );
+  const matcherPrototype = defineOwnProperties(
+    matcherConstructor.prototype,
+    getOwnPropertyDescriptors(Matcher.prototype),
+    { constructor: { value: matcherConstructor } },
+  );
+
+  return { Matcher: matcherConstructor };
+})();
+
+export const {
+  /**
+   * Returns the result of converting the provided value to A·S·C·I·I
+   * lowercase.
+   */
+  asciiLowercase,
+
+  /**
+   * Returns the result of converting the provided value to A·S·C·I·I
+   * uppercase.
+   */
+  asciiUppercase,
+} = (() => {
+  const {
+    toLowerCase: stringToLowercase,
+    toUpperCase: stringToUppercase,
+  } = String.prototype;
+  return {
+    asciiLowercase: ($) =>
+      stringReplaceAll(
+        `${$}`,
+        /[A-Z]/gu,
+        makeCallable(stringToLowercase),
+      ),
+    asciiUppercase: ($) =>
+      stringReplaceAll(
+        `${$}`,
+        /[a-z]/gu,
+        makeCallable(stringToUppercase),
+      ),
+  };
+})();
+
+export const {
+  /**
+   * Returns an iterator over the code units in the string
+   * representation of the provided value.
+   */
+  codeUnits,
+
+  /**
+   * Returns an iterator over the codepoints in the string
+   * representation of the provided value.
+   */
+  codepoints,
+
+  /**
+   * Returns an iterator over the scalar values in the string
+   * representation of the provided value.
+   *
+   * Codepoints which are not valid Unicode scalar values are replaced
+   * with U+FFFF.
+   */
+  scalarValues,
+
+  /**
+   * Returns the result of converting the provided value to a string of
+   * scalar values by replacing (unpaired) surrogate values with
+   * U+FFFD.
+   */
+  scalarValueString,
+} = (() => {
+  const {
+    iterator: iteratorSymbol,
+    toStringTag: toStringTagSymbol,
+  } = Symbol;
+  const { [iteratorSymbol]: arrayIterator } = Array.prototype;
+  const arrayIteratorPrototype = Object.getPrototypeOf(
+    [][iteratorSymbol](),
+  );
+  const { next: arrayIteratorNext } = arrayIteratorPrototype;
+  const iteratorPrototype = Object.getPrototypeOf(
+    arrayIteratorPrototype,
+  );
+  const { [iteratorSymbol]: stringIterator } = String.prototype;
+  const stringIteratorPrototype = Object.getPrototypeOf(
+    ""[iteratorSymbol](),
+  );
+  const { next: stringIteratorNext } = stringIteratorPrototype;
+
+  /**
+   * An iterator object for iterating over code values (either code
+   * units or codepoints) in a string.
+   *
+   * ※ This class is not exposed, although its methods are (through
+   * the prototypes of string code value iterator objects).
+   */
+  const StringCodeValueIterator = class extends identity {
+    #allowSurrogates;
+    #baseIterator;
+
+    /**
+     * Constructs a new string code value iterator from the provided
+     * base iterator.
+     *
+     * If the provided base iterator is an array iterator, this is a
+     * code unit iterator.  If the provided iterator is a string
+     * iterator and surrogates are allowed, this is a codepoint
+     * iterator. If the provided iterator is a string iterator and
+     * surrogates are not allowed, this is a scalar value iterator.
+     */
+    constructor(baseIterator, allowSurrogates = true) {
+      super(objectCreate(stringCodeValueIteratorPrototype));
+      this.#allowSurrogates = !!allowSurrogates;
+      this.#baseIterator = baseIterator;
+    }
+
+    /** Provides the next code value in the iterator. */
+    next() {
+      const baseIterator = this.#baseIterator;
+      switch (getPrototype(baseIterator)) {
+        case arrayIteratorPrototype: {
+          // The base iterator is iterating over U·C·S characters.
+          const {
+            value: ucsCharacter,
+            done,
+          } = call(arrayIteratorNext, baseIterator, []);
+          return done
+            ? { value: undefined, done: true }
+            : { value: getCodeUnit(ucsCharacter, 0), done: false };
+        }
+        case stringIteratorPrototype: {
+          // The base iterator is iterating over Unicode characters.
+          const {
+            value: character,
+            done,
+          } = call(stringIteratorNext, baseIterator, []);
+          if (done) {
+            // The base iterator has been exhausted.
+            return { value: undefined, done: true };
+          } else {
+            // The base iterator provided a character; yield the
+            // codepoint.
+            const codepoint = getCodepoint(character, 0);
+            return {
+              value: this.#allowSurrogates || codepoint <= 0xD7FF ||
+                  codepoint >= 0xE000
+                ? codepoint
+                : 0xFFFD,
+              done: false,
+            };
+          }
+        }
+        default: {
+          // Should not be possible!
+          throw new TypeError(
+            "Piscēs: Unrecognized base iterator type in %StringCodeValueIterator%.",
+          );
+        }
+      }
+    }
+  };
+
+  const {
+    next: stringCodeValueIteratorNext,
+  } = StringCodeValueIterator.prototype;
+  const stringCodeValueIteratorPrototype = objectCreate(
+    iteratorPrototype,
+    {
+      next: {
+        configurable: true,
+        enumerable: false,
+        value: stringCodeValueIteratorNext,
+        writable: true,
+      },
+      [toStringTagSymbol]: {
+        configurable: true,
+        enumerable: false,
+        value: "String Code Value Iterator",
+        writable: false,
+      },
+    },
+  );
+  const scalarValueIterablePrototype = {
+    [iteratorSymbol]() {
+      return {
+        next: bind(
+          stringCodeValueIteratorNext,
+          new StringCodeValueIterator(
+            call(stringIterator, this.source, []),
+            false,
+          ),
+          [],
+        ),
+      };
+    },
+  };
+
+  return {
+    codeUnits: ($) =>
+      new StringCodeValueIterator(call(arrayIterator, `${$}`, [])),
+    codepoints: ($) =>
+      new StringCodeValueIterator(
+        call(stringIterator, `${$}`, []),
+        true,
+      ),
+    scalarValues: ($) =>
+      new StringCodeValueIterator(
+        call(stringIterator, `${$}`, []),
+        false,
+      ),
+    scalarValueString: ($) =>
+      stringFromCodepoints(...objectCreate(
+        scalarValueIterablePrototype,
+        { source: { value: `${$}` } },
+      )),
+  };
+})();
+
 /**
- * Returns the result of converting the provided value to A·S·C·I·I
- * lowercase.
+ * Returns an iterator over the codepoints in the string representation
+ * of the provided value according to the algorithm of
+ * String::[Symbol.iterator].
  */
-export const asciiLowercase = ($) =>
-  `${$}`.replaceAll(
-    /[A-Z]/gu,
-    Function.prototype.call.bind(String.prototype.toLowerCase),
-  );
+export const characters = makeCallable(
+  String.prototype[Symbol.iterator],
+);
 
 /**
- * Returns the result of converting the provided value to A·S·C·I·I
- * uppercase.
+ * Returns the character at the provided position in the string
+ * representation of the provided value according to the algorithm of
+ * String::codePointAt.
  */
-export const asciiUppercase = ($) =>
-  `${$}`.replaceAll(
-    /[a-z]/gu,
-    Function.prototype.call.bind(String.prototype.toUpperCase),
-  );
+export const getCharacter = ($, pos) => {
+  const codepoint = getCodepoint($, pos);
+  return codepoint == null
+    ? undefined
+    : stringFromCodepoints(codepoint);
+};
 
 /**
- * Returns the result of converting the provided value to a string of
- * scalar values by replacing (unpaired) surrogate values with U+FFFD.
+ * Returns the code unit at the provided position in the string
+ * representation of the provided value according to the algorithm of
+ * String::charAt.
  */
-export const scalarValueString = ($) =>
-  String.fromCodePoint(
-    ...function* () {
-      for (const char of `${$}`) {
-        const scalar = char.codePointAt(0);
-        yield scalar >= 0xD800 && scalar <= 0xDFFF ? 0xFFFD : scalar;
-      }
-    }(),
-  );
+export const getCodeUnit = makeCallable(String.prototype.charCodeAt);
+
+/**
+ * Returns the codepoint at the provided position in the string
+ * representation of the provided value according to the algorithm of
+ * String::codePointAt.
+ */
+export const getCodepoint = makeCallable(String.prototype.codePointAt);
+
+/**
+ * Returns the index of the first occurrence of the search string in
+ * the string representation of the provided value according to the
+ * algorithm of String::indexOf.
+ */
+export const getFirstSubstringIndex = makeCallable(
+  String.prototype.indexOf,
+);
+
+/**
+ * Returns the index of the last occurrence of the search string in the
+ * string representation of the provided value according to the
+ * algorithm of String::lastIndexOf.
+ */
+export const getLastSubstringIndex = makeCallable(
+  String.prototype.lastIndexOf,
+);
+
+/**
+ * Returns the result of joining the provided iterable.
+ *
+ * If no separator is provided, it defaults to ",".
+ *
+ * If a value is nullish, it will be stringified as the empty string.
+ */
+export const join = (() => {
+  const { join: arrayJoin } = Array.prototype;
+  const join = ($, separator = ",") =>
+    call(arrayJoin, [...$], [`${separator}`]);
+  return join;
+})();
+
+export const {
+  /**
+   * Returns a string created from the raw value of the tagged template
+   * literal.
+   *
+   * ※ This is an alias for String.raw.
+   */
+  raw: rawString,
+
+  /**
+   * Returns a string created from the provided code units.
+   *
+   * ※ This is an alias for String.fromCharCode.
+   */
+  fromCharCode: stringFromCodeUnits,
+
+  /**
+   * Returns a string created from the provided codepoints.
+   *
+   * ※ This is an alias for String.fromCodePoint.
+   */
+  fromCodePoint: stringFromCodepoints,
+} = String;
 
 /**
  * Returns the result of splitting the provided value on A·S·C·I·I
  * whitespace.
  */
 export const splitOnASCIIWhitespace = ($) =>
-  stripAndCollapseASCIIWhitespace($).split(" ");
+  stringSplit(stripAndCollapseASCIIWhitespace($), " ");
 
 /**
  * Returns the result of splitting the provided value on commas,
  * trimming A·S·C·I·I whitespace from the resulting tokens.
  */
 export const splitOnCommas = ($) =>
-  stripLeadingAndTrailingASCIIWhitespace(
-    `${$}`.replaceAll(
-      /[\n\r\t\f ]*,[\n\r\t\f ]*/gu,
-      ",",
+  stringSplit(
+    stripLeadingAndTrailingASCIIWhitespace(
+      stringReplaceAll(
+        `${$}`,
+        /[\n\r\t\f ]*,[\n\r\t\f ]*/gu,
+        ",",
+      ),
     ),
-  ).split(",");
+    ",",
+  );
 
 /**
- * Returns the result of stripping leading and trailing A·S·C·I·I
- * whitespace from the provided value.
+ * Returns the result of catenating the string representations of the
+ * provided values, returning a new string according to the algorithm
+ * of String::concat.
+ */
+export const stringCatenate = makeCallable(String.prototype.concat);
+
+/**
+ * Returns whether the string representation of the provided value ends
+ * with the provided search string according to the algorithm of
+ * String::endsWith.
+ */
+export const stringEndsWith = makeCallable(String.prototype.endsWith);
+
+/**
+ * Returns whether the string representation of the provided value
+ * contains the provided search string according to the algorithm of
+ * String::includes.
+ */
+export const stringIncludes = makeCallable(String.prototype.includes);
+
+/**
+ * Returns the result of matching the string representation of the
+ * provided value with the provided matcher according to the algorithm
+ * of String::match.
+ */
+export const stringMatch = makeCallable(String.prototype.match);
+
+/**
+ * Returns the result of matching the string representation of the
+ * provided value with the provided matcher according to the algorithm
+ * of String::matchAll.
+ */
+export const stringMatchAll = makeCallable(String.prototype.matchAll);
+
+/**
+ * Returns the normalized form of the string representation of the
+ * provided value according to the algorithm of String::matchAll.
+ */
+export const stringNormalize = makeCallable(
+  String.prototype.normalize,
+);
+
+/**
+ * Returns the result of padding the end of the string representation
+ * of the provided value padded until it is the desired length
+ * according to the algorithm of String::padEnd.
+ */
+export const stringPadEnd = makeCallable(String.prototype.padEnd);
+
+/**
+ * Returns the result of padding the start of the string representation
+ * of the provided value padded until it is the desired length
+ * according to the algorithm of String::padStart.
+ */
+export const stringPadStart = makeCallable(String.prototype.padStart);
+
+/**
+ * Returns the result of repeating the string representation of the
+ * provided value the provided number of times according to the
+ * algorithm of String::repeat.
+ */
+export const stringRepeat = makeCallable(String.prototype.repeat);
+
+/**
+ * Returns the result of replacing the string representation of the
+ * provided value with the provided replacement, using the provided
+ * matcher and according to the algorithm of String::replace.
  */
-export const stripLeadingAndTrailingASCIIWhitespace = ($) =>
-  /^[\n\r\t\f ]*([^]*?)[\n\r\t\f ]*$/u.exec($)[1];
+export const stringReplace = makeCallable(String.prototype.replace);
+
+/**
+ * Returns the result of replacing the string representation of the
+ * provided value with the provided replacement, using the provided
+ * matcher and according to the algorithm of String::replaceAll.
+ */
+export const stringReplaceAll = makeCallable(
+  String.prototype.replaceAll,
+);
+
+/**
+ * Returns the result of searching the string representation of the
+ * provided value using the provided matcher and according to the
+ * algorithm of String::search.
+ */
+export const stringSearch = makeCallable(String.prototype.search);
+
+/**
+ * Returns a slice of the string representation of the provided value
+ * according to the algorithm of String::slice.
+ */
+export const stringSlice = makeCallable(String.prototype.slice);
+
+/**
+ * Returns the result of splitting of the string representation of the
+ * provided value on the provided separator according to the algorithm
+ * of String::split.
+ */
+export const stringSplit = makeCallable(String.prototype.split);
+
+/**
+ * Returns whether the string representation of the provided value
+ * starts with the provided search string according to the algorithm of
+ * String::startsWith.
+ */
+export const stringStartsWith = makeCallable(
+  String.prototype.startsWith,
+);
+
+/**
+ * Returns the `[[StringData]]` of the provided value.
+ *
+ * ☡ This function will throw if the provided object does not have a
+ * `[[StringData]]` internal slot.
+ */
+export const stringValue = makeCallable(String.prototype.valueOf);
 
 /**
  * Returns the result of stripping leading and trailing A·S·C·I·I
  * whitespace from the provided value and collapsing other A·S·C·I·I
- * whitespace in the provided value.
+ * whitespace in the string representation of the provided value.
  */
 export const stripAndCollapseASCIIWhitespace = ($) =>
   stripLeadingAndTrailingASCIIWhitespace(
-    `${$}`.replaceAll(
+    stringReplaceAll(
+      `${$}`,
       /[\n\r\t\f ]+/gu,
       " ",
     ),
   );
+
+/**
+ * Returns the result of stripping leading and trailing A·S·C·I·I
+ * whitespace from the string representation of the provided value.
+ */
+export const stripLeadingAndTrailingASCIIWhitespace = (() => {
+  const { exec: reExec } = RegExp.prototype;
+  return ($) =>
+    call(reExec, /^[\n\r\t\f ]*([^]*?)[\n\r\t\f ]*$/u, [$])[1];
+})();
+
+/**
+ * Returns a substring of the string representation of the provided
+ * value according to the algorithm of String::substring.
+ */
+export const substring = makeCallable(String.prototype.substring);
+
+/**
+ * Returns the result of converting the provided value to a string.
+ *
+ * ☡ This method throws for symbols and other objects without a string
+ * representation.
+ */
+export const toString = ($) => `${$}`;