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

diff --git a/string.js b/string.js
index 17e8736..e8126d1 100644
--- a/string.js
+++ b/string.js
@@ -1,81 +1,809 @@
 // ♓🌟 Piscēs ∷ string.js
 // ====================================================================
 //
-// Copyright © 2022 Lady [@ Lady’s Computer].
+// Copyright © 2022–2023 Lady [@ Lady’s Computer].
 //
 // This Source Code Form is subject to the terms of the Mozilla Public
 // 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,
+  createArrowFunction,
+  createCallableFunction,
+  identity,
+} from "./function.js";
+import {
+  arrayIteratorFunction,
+  stringIteratorFunction,
+} from "./iterable.js";
+import {
+  defineOwnDataProperty,
+  defineOwnProperties,
+  getOwnPropertyDescriptors,
+  objectCreate,
+  setPropertyValues,
+  setPrototype,
+} from "./object.js";
+import { sameValue, toLength, UNDEFINED } from "./value.js";
+
+const RE = RegExp;
+const { prototype: rePrototype } = RE;
+const { prototype: arrayPrototype } = Array;
+const { prototype: stringPrototype } = String;
+
+const { exec: reExec } = rePrototype;
+
+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 { toString: reToString } = rePrototype;
+  const getDotAll =
+    Object.getOwnPropertyDescriptor(rePrototype, "dotAll").get;
+  const getFlags =
+    Object.getOwnPropertyDescriptor(rePrototype, "flags").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: ${source}`,
+          );
+        } else {
+          // The provided regular expression has a unicode flag.
+          return new RE(source);
+        }
+      })();
+      if (constraint !== null && typeof constraint !== "function") {
+        throw new TypeError(
+          "Piscēs: Cannot construct Matcher: Constraint is not callable.",
+        );
+      } else {
+        this.#constraint = constraint;
+        return defineOwnProperties(
+          setPrototype(this, matcherPrototype),
+          {
+            lastIndex: setPropertyValues(objectCreate(null), {
+              configurable: false,
+              enumerable: false,
+              value: 0,
+              writable: false,
+            }),
+            name: defineOwnDataProperty(
+              objectCreate(null),
+              "value",
+              name != null
+                ? `${name}`
+                : `Matcher(${call(reToString, regExp, [])})`,
+            ),
+          },
+        );
+      }
+    }
+
+    /** Gets whether the dot‐all flag is present on this `Matcher`. */
+    get dotAll() {
+      return call(getDotAll, this.#regExp, []);
+    }
+
+    /**
+     * Executes this `Matcher` on the provided value and returns the
+     * result if there is a match, or null otherwise.
+     *
+     * Matchers only match if they can match the entire value on the
+     * first attempt.
+     *
+     * ☡ The match result returned by this method will be the same as
+     * that passed to the constraint function—and may have been
+     * modified by said function prior to being returned.
+     */
+    exec($) {
+      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 the flags present on this `Matcher`.
+     *
+     * ※ This needs to be defined because the internal `RegExp` object
+     * may have flags which are not yet recognized by ♓🌟 Piscēs.
+     */
+    get flags() {
+      return call(getFlags, this.#regExp, []);
+    }
+
+    /** Gets whether the global flag is present on this `Matcher`. */
+    get global() {
+      return call(getGlobal, this.#regExp, []);
+    }
+
+    /**
+     * Gets whether the has‐indices flag is present on this `Matcher`.
+     */
+    get hasIndices() {
+      return call(getHasIndices, this.#regExp, []);
+    }
+
+    /**
+     * Gets whether the ignore‐case 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 = Object.defineProperties(
+    class extends RegExp {
+      constructor(...args) {
+        return new Matcher(...args);
+      }
+    },
+    {
+      name: defineOwnDataProperty(
+        Object.create(null),
+        "value",
+        "Matcher",
+      ),
+      length: defineOwnDataProperty(Object.create(null), "value", 1),
+    },
+  );
+  const matcherPrototype = defineOwnProperties(
+    matcherConstructor.prototype,
+    getOwnPropertyDescriptors(Matcher.prototype),
+    {
+      constructor: defineOwnDataProperty(
+        Object.create(null),
+        "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,
+  } = stringPrototype;
+  return {
+    asciiLowercase: ($) =>
+      stringReplaceAll(
+        `${$}`,
+        /[A-Z]/gu,
+        createCallableFunction(stringToLowercase),
+      ),
+    asciiUppercase: ($) =>
+      stringReplaceAll(
+        `${$}`,
+        /[a-z]/gu,
+        createCallableFunction(stringToUppercase),
+      ),
+  };
+})();
+
 /**
- * Returns the result of converting the provided value to A·S·C·I·I
- * lowercase.
+ * Returns −0 if the provided argument is "-0"; returns a number
+ * representing the index if the provided argument is a canonical
+ * numeric index string; otherwise, returns undefined.
+ *
+ * There is no clamping of the numeric index, but note that numbers
+ * above 2^53 − 1 are not safe nor valid integer indices.
  */
-export const asciiLowercase = ($) =>
-  `${$}`.replaceAll(
-    /[A-Z]/gu,
-    Function.prototype.call.bind(String.prototype.toLowerCase),
+export const canonicalNumericIndexString = ($) => {
+  if (typeof $ !== "string") {
+    return UNDEFINED;
+  } else if ($ === "-0") {
+    return -0;
+  } else {
+    const n = +$;
+    return $ === `${n}` ? n : UNDEFINED;
+  }
+};
+
+export const {
+  /**
+   * Returns an iterator over the codepoints in the string representation
+   * of the provided value according to the algorithm of
+   * `String::[Symbol.iterator]`.
+   */
+  characters,
+
+  /**
+   * Returns an iterator over the code units in the string
+   * representation of the provided value.
+   */
+  codeUnits,
+
+  /**
+   * Returns an iterator over the codepoints in the string
+   * representation of the provided value.
+   */
+  codepoints,
+
+  /**
+   * Returns an iterator over the scalar values in the string
+   * representation of the provided value.
+   *
+   * Codepoints which are not valid Unicode scalar values are replaced
+   * with U+FFFD.
+   */
+  scalarValues,
+} = (() => {
+  const generateCharacters = function* (character) {
+    yield character;
+  };
+  const generateCodeUnits = function* (ucsCharacter) {
+    yield getCodeUnit(ucsCharacter, 0);
+  };
+  const generateCodepoints = function* (character) {
+    const { allowSurrogates } = this;
+    const codepoint = getCodepoint(character, 0);
+    yield allowSurrogates || codepoint <= 0xD7FF || codepoint >= 0xE000
+      ? codepoint
+      : 0xFFFD;
+  };
+
+  const charactersIterator = stringIteratorFunction(
+    generateCharacters,
+    "String Character Iterator",
   );
+  const codeUnitsIterator = arrayIteratorFunction(
+    generateCodeUnits,
+    "String Code Unit Iterator",
+  );
+  const codepointsIterator = stringIteratorFunction(
+    bind(generateCodepoints, { allowSurrogates: true }, []),
+    "String Codepoint Iterator",
+  );
+  const scalarValuesIterator = stringIteratorFunction(
+    bind(generateCodepoints, { allowSurrogates: false }, []),
+    "String Scalar Value Iterator",
+  );
+
+  return {
+    characters: ($) => charactersIterator(`${$}`),
+    codeUnits: ($) => codeUnitsIterator(`${$}`),
+    codepoints: ($) => codepointsIterator(`${$}`),
+    scalarValues: ($) => scalarValuesIterator(`${$}`),
+  };
+})();
 
 /**
- * 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($, pos);
+  return codepoint == null
+    ? UNDEFINED
+    : stringFromCodepoints(codepoint);
+};
+
+export const {
+  /**
+   * Returns the code unit at the provided position in the string
+   * representation of the provided value according to the algorithm of
+   * `String::charAt`, except that out‐of‐bounds values return undefined
+   * in place of nan.
+   */
+  getCodeUnit,
+
+  /**
+   * Returns a string created from the provided code units.
+   *
+   * ※ This is effectively an alias for `String.fromCharCode`, but
+   * with the same error behaviour as `String.fromCodePoint`.
+   *
+   * ☡ This function throws an error if provided with an argument which
+   * is not an integral number from 0 to FFFF₁₆ inclusive.
+   */
+  stringFromCodeUnits,
+
+  /**
+   * Returns the result of catenating the string representations of the
+   * provided values, returning a new string according to the algorithm
+   * of `String::concat`.
+   *
+   * ※ If no arguments are given, this function returns the empty
+   * string. This is different behaviour than if an explicit undefined
+   * first argument is given, in which case the resulting string will
+   * begin with `"undefined"`.
+   */
+  stringCatenate,
+} = (() => {
+  const { fromCharCode } = String;
+  const { charCodeAt, concat } = String.prototype;
+  const {
+    isInteger: isIntegralNumber,
+    isNaN: isNan,
+  } = Number;
+
+  return {
+    getCodeUnit: ($, n) => {
+      const codeUnit = call(charCodeAt, $, [n]);
+      return isNan(codeUnit) ? UNDEFINED : codeUnit;
+    },
+    stringCatenate: Object.defineProperties(
+      (...args) => call(concat, "", args),
+      { name: { value: "stringCatenate" }, length: { value: 2 } },
+    ),
+    stringFromCodeUnits: Object.defineProperties(
+      (...codeUnits) => {
+        for (let index = 0; index < codeUnits.length; ++index) {
+          // Iterate over each provided code unit and throw if it is
+          // out of range.
+          const nextCU = +codeUnits[index];
+          if (
+            !isIntegralNumber(nextCU) || nextCU < 0 || nextCU > 0xFFFF
+          ) {
+            // The code unit is not an integral number between 0 and
+            // 0xFFFF.
+            throw new RangeError(
+              `Piscēs: Code unit out of range: ${nextCU}.`,
+            );
+          } else {
+            // The code unit is acceptable.
+            /* do nothing */
+          }
+        }
+        return call(fromCharCode, UNDEFINED, codeUnits);
+      },
+      { name: { value: "stringFromCodeUnits" }, length: { value: 1 } },
+    ),
+  };
+})();
 
 /**
- * Returns the result of converting the provided value to a string of
- * scalar values by replacing (unpaired) surrogate values with U+FFFD.
- */
-export const scalarValueString = ($) =>
-  String.fromCodePoint(
-    ...function* () {
-      for (const char of `${$}`) {
-        const scalar = char.codePointAt(0);
-        yield scalar >= 0xD800 && scalar <= 0xDFFF ? 0xFFFD : scalar;
-      }
-    }(),
-  );
+ * Returns the codepoint at the provided position in the string
+ * representation of the provided value according to the algorithm of
+ * `String::codePointAt`.
+ */
+export const getCodepoint = createCallableFunction(
+  stringPrototype.codePointAt,
+  { name: "getCodepoint" },
+);
+
+/**
+ * Returns the index of the first occurrence of the search string in
+ * the string representation of the provided value according to the
+ * algorithm of `String::indexOf`.
+ */
+export const getFirstSubstringIndex = createCallableFunction(
+  stringPrototype.indexOf,
+  { name: "getFirstSubstringIndex" },
+);
+
+/**
+ * Returns the index of the last occurrence of the search string in the
+ * string representation of the provided value according to the
+ * algorithm of `String::lastIndexOf`.
+ */
+export const getLastSubstringIndex = createCallableFunction(
+  stringPrototype.lastIndexOf,
+  { name: "getLastSubstringIndex" },
+);
+
+/** Returns whether the provided value is an array index. */
+export const isArrayIndexString = ($) => {
+  const value = canonicalNumericIndexString($);
+  if (value !== UNDEFINED) {
+    // The provided value is a canonical numeric index string; return
+    // whether it is in range for array indices.
+    return sameValue(value, 0) ||
+      value === toLength(value) && value > 0 && value < -1 >>> 0;
+  } else {
+    // The provided value is not a canonical numeric index string.
+    return false;
+  }
+};
+
+/** Returns whether the provided value is an integer index string. */
+export const isIntegerIndexString = ($) => {
+  const value = canonicalNumericIndexString($);
+  if (value !== UNDEFINED) {
+    // The provided value is a canonical numeric index string; return
+    // whether it is in range for integer indices.
+    return sameValue(value, 0) ||
+      value === toLength(value) && value > 0;
+  } else {
+    // The provided value is not a canonical numeric index string.
+    return false;
+  }
+};
+
+/**
+ * Returns the result of joining the provided iterable.
+ *
+ * If no separator is provided, it defaults to ",".
+ *
+ * If a value is nullish, it will be stringified as the empty string.
+ */
+export const join = (() => {
+  const { join: arrayJoin } = arrayPrototype;
+  const join = ($, separator) =>
+    call(
+      arrayJoin,
+      [...$],
+      [separator === UNDEFINED ? "," : `${separator}`],
+    );
+  return join;
+})();
+
+/**
+ * Returns a string created from the raw value of the tagged template
+ * literal.
+ *
+ * ※ This is effectively an alias for `String.raw`.
+ */
+export const rawString = createArrowFunction(String.raw, {
+  name: "rawString",
+});
 
 /**
- * Returns the result of splitting the provided value on A·S·C·I·I
+ * Returns a string created from the provided codepoints.
+ *
+ * ※ This is effectively an alias for `String.fromCodePoint`.
+ *
+ * ☡ This function throws an error if provided with an argument which
+ * is not an integral number from 0 to 10FFFF₁₆ inclusive.
+ */
+export const stringFromCodepoints = createArrowFunction(
+  String.fromCodePoint,
+  { name: "stringFromCodepoints" },
+);
+
+/**
+ * Returns the result of splitting the provided value on Ascii
  * whitespace.
  */
-export const splitOnASCIIWhitespace = ($) =>
-  stripAndCollapseASCIIWhitespace($).split(" ");
+export const splitOnAsciiWhitespace = ($) =>
+  stringSplit(stripAndCollapseAsciiWhitespace($), " ");
 
 /**
  * Returns the result of splitting the provided value on commas,
- * trimming A·S·C·I·I whitespace from the resulting tokens.
+ * trimming Ascii 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 whether the string representation of the provided value ends
+ * with the provided search string according to the algorithm of
+ * `String::endsWith`.
+ */
+export const stringEndsWith = createCallableFunction(
+  stringPrototype.endsWith,
+  { name: "stringEndsWith" },
+);
+
+/**
+ * Returns whether the string representation of the provided value
+ * contains the provided search string according to the algorithm of
+ * `String::includes`.
+ */
+export const stringIncludes = createCallableFunction(
+  stringPrototype.includes,
+  { name: "stringIncludes" },
+);
+
+/**
+ * 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 = createCallableFunction(
+  stringPrototype.match,
+  { name: "stringMatch" },
+);
+
+/**
+ * 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 = createCallableFunction(
+  stringPrototype.matchAll,
+  { name: "stringMatchAll" },
+);
+
+/**
+ * Returns the normalized form of the string representation of the
+ * provided value according to the algorithm of `String::normalize`.
+ */
+export const stringNormalize = createCallableFunction(
+  stringPrototype.normalize,
+  { name: "stringNormalize" },
+);
 
 /**
- * Returns the result of stripping leading and trailing A·S·C·I·I
- * whitespace from the provided value.
+ * 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 stripLeadingAndTrailingASCIIWhitespace = ($) =>
-  /^[\n\r\t\f ]*([^]*?)[\n\r\t\f ]*$/u.exec($)[1];
+export const stringPadEnd = createCallableFunction(
+  stringPrototype.padEnd,
+  { name: "stringPadEnd" },
+);
 
 /**
- * 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.
+ * 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 stripAndCollapseASCIIWhitespace = ($) =>
-  stripLeadingAndTrailingASCIIWhitespace(
-    `${$}`.replaceAll(
+export const stringPadStart = createCallableFunction(
+  stringPrototype.padStart,
+  { name: "stringPadStart" },
+);
+
+/**
+ * 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 = createCallableFunction(
+  stringPrototype.repeat,
+  { name: "stringRepeat" },
+);
+
+/**
+ * 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 stringReplace = createCallableFunction(
+  stringPrototype.replace,
+  { name: "stringReplace" },
+);
+
+/**
+ * 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 = createCallableFunction(
+  stringPrototype.replaceAll,
+  { name: "stringReplaceAll" },
+);
+
+/**
+ * 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 = createCallableFunction(
+  stringPrototype.search,
+  { name: "stringSearch" },
+);
+
+/**
+ * Returns a slice of the string representation of the provided value
+ * according to the algorithm of `String::slice`.
+ */
+export const stringSlice = createCallableFunction(
+  stringPrototype.slice,
+  { name: "stringSlice" },
+);
+
+/**
+ * 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 = createCallableFunction(
+  stringPrototype.split,
+  { name: "stringSplit" },
+);
+
+/**
+ * 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 = createCallableFunction(
+  stringPrototype.startsWith,
+  { name: "stringStartsWith" },
+);
+
+/**
+ * Returns the value of the provided string.
+ *
+ * ※ This is effectively an alias for the `String::valueOf`.
+ *
+ * ☡ This function throws if the provided argument is not a string and
+ * does not have a `[[StringData]]` slot.
+ */
+export const stringValue = createCallableFunction(
+  stringPrototype.valueOf,
+  { name: "stringValue" },
+);
+
+/**
+ * Returns the result of stripping leading and trailing Ascii
+ * whitespace from the provided value and collapsing other Ascii
+ * whitespace in the string representation of the provided value.
+ */
+export const stripAndCollapseAsciiWhitespace = ($) =>
+  stripLeadingAndTrailingAsciiWhitespace(
+    stringReplaceAll(
+      `${$}`,
       /[\n\r\t\f ]+/gu,
       " ",
     ),
   );
+
+/**
+ * Returns the result of stripping leading and trailing Ascii
+ * whitespace from the string representation of the provided value.
+ */
+export const stripLeadingAndTrailingAsciiWhitespace = ($) =>
+  call(reExec, /^[\n\r\t\f ]*([^]*?)[\n\r\t\f ]*$/u, [$])[1];
+
+/**
+ * Returns a substring of the string representation of the provided
+ * value according to the algorithm of `String::substring`.
+ */
+export const substring = createCallableFunction(
+  stringPrototype.substring,
+);
+
+/**
+ * Returns the result of converting the provided value to a string of
+ * scalar values by replacing (unpaired) surrogate values with
+ * U+FFFD.
+ */
+export const toScalarValueString = createCallableFunction(
+  String.prototype.toWellFormed,
+  { name: "toScalarValueString" },
+);
+
+/**
+ * Returns the result of converting the provided value to a string.
+ *
+ * ☡ This method throws for symbols and other objects without a string
+ * representation.
+ */
+export const toString = ($) => `${$}`;