/**
 * Regular Expression Specification
 * - Provide basic elements of Javascript/Type Regular Expression
 * @see [Regular Expressions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions)
 */
export declare class RegExpSpec {
    /**
     * `\`, backslash.
     * @see [backslash](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-backslash)
     */
    static get backslash(): string;
    /**
     * `^`,
     * Matches beginning of input.
     * If the multiline flag is set to true, also matches immediately after a line break character.
     *
     * @see: [Caret](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-caret)
     */
    static get begin(): string;
    /**
     * `$`,
     * Matches end of input.
     * If the multiline flag is set to true, also matches immediately before a line break character.
     *
     * @see [dollar](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-dollar)
     */
    static get end(): string;
    /**
     * `*`,
     * Matches the preceding expression 0 or more times. Equivalent to `{0,}`.
     *
     * @see [asterisk](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-asterisk)
     */
    static get more(): string;
    /**
     * `*`,
     * Matches the preceding expression 0 or more times. Equivalent to `{0,}`.
     *
     * @see [asterisk](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-asterisk)
     */
    static get asterisk(): string;
    /**
     * `+`,
     * Matches the preceding expression 1 or more times. Equivalent to `{1,}`.
     *
     * @see [plus](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-plus)
     */
    static get oneOrMore(): string;
    /**
     * `+`,
     * Matches the preceding expression 1 or more times. Equivalent to `{1,}`.
     *
     * @see [plus](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-plus)
     */
    static get plus(): string;
    /**
     * `?`
     * Matches the preceding expression 0 or 1 time. Equivalent to `{0,1}`.
     *
     * @see [questionmark](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-questionmark)
     */
    static get zeroOrOne(): string;
    /**
     * `?`,
     * Matches the preceding expression 0 or 1 time. Equivalent to `{0,1}`.
     *
     * @see [questionmark](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-questionmark)
     */
    static get questionmark(): string;
    /**
     * `.`,
     * Matches any single character except the newline character, by default.
     *
     * @see [dot](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-dot)
     */
    static get any(): string;
    /**
     * `.`,
     * Matches any single character except the newline character, by default.
     *
     * @see [dot](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-dot)
     */
    static get dot(): string;
    /**
     * `(x)`, Matches `x` and remembers the match.
     * The parentheses are called capturing parentheses.
     * `(?<name>:x)`, Named capturing group: Matches x and stores it
     * on the groups property of the returned matches under the name specified by <Name>.
     *
     * @param x expression
     * @param name name
     *
     * @see [capturing parentheses](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-capturing-parentheses)
     * @see [Groups and Ranges](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Groups_and_Ranges)
     */
    static capturingParentheses(x: string | RegExp, name?: string): string;
    /**
     * `(?:x)`, Matches `x` but does not remember the match.
     * The parentheses are called non-capturing parentheses.
     * @param x expression
     *
     * @see [non capturing parentheses](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-non-capturing-parentheses)
     */
    static nonCapturingParentheses(x: string | RegExp): string;
    /**
     * `x(?=y)`,
     * Matches `x` only if `x` is followed by `y`. This is called a lookahead.
     *
     * @param x expression
     * @param followedBy the followed by expression
     *
     * @see [lookahead](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-lookahead)
     */
    static lookahead(x: string | RegExp, followedBy: string | RegExp): string;
    /**
     * `x(?!y)`
     * Matches `x` only if `x` is not followed by `y`.
     * This is called a negated lookahead.
     * @param x expression
     * @param notFollowedBy the not followed by expression
     *
     * @see [negated look ahead](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-negated-look-ahead)
     */
    static negatedLookahead(x: string | RegExp, notFollowedBy: string | RegExp): string;
    /**
     * `(?<=y)x`,
     * Matches `x` only if `x` is preceded by `y`.
     * This is called a lookbehind.
     *
     * @param x expression
     * @param precededBy the preceded by expression
     *
     * @see [lookbehind](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-lookbehind)
     */
    static lookbehind(x: string | RegExp, precededBy: string | RegExp): string;
    /**
     * `(?<!y)x`,
     * Matches `x` only if `x` is not preceded by `y`.
     * This is called a negated lookbehind.
     *
     * @param x expression
     * @param notPrecededBy the not preceded by expression
     *
     * @see [negative lookbehind](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-negative-lookbehind)
     */
    static negatedLookbehind(x: string | RegExp, notPrecededBy: string | RegExp): string;
    /**
     * `x|y`,
     * Matches 'x', or 'y' (if there is no match for 'x').
     *
     * @param items expression
     *
     * @see [or](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-or)
     */
    static or(...items: string[] | RegExp[]): string;
    /**
     * `{n}`,
     * Matches exactly n occurrences of the preceding expression. N must be a positive integer.
     *
     * @param n times of occurrences
     *
     * @see [quantifier](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-quantifier)
     */
    static occurrence(n: number): string;
    /**
     * `(n, }`, `{n, m}`,
     * Matches at least `n` occurrences of the preceding expression. `N` must be a positive integer.
     * Where `n` and `m` are positive integers and `n <= m`.
     * Matches at least `n` and at most `m` occurrences of the preceding expression.
     * When `m` is omitted, it's treated as `∞`.
     *
     * @param n at least occurrences
     * @param m (optional) at most occurrences
     *
     * @see [quantifier](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-quantifier)
     * @see [quantifier-range](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-quantifier-range)
     */
    static occurrenceOrMore(n: number, m?: number): string;
    /**
     * `[xyz]`,
     * Character set.
     *
     * @see [character set](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-character-set)
     */
    static characterSet(...chars: string[]): string;
    /**
     * `[^xyz]`,
     * A negated or complemented character set.
     *
     * @see [negated character set](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-negated-character-set)
     */
    static negatedCharacterSet(...chars: string[]): string;
    /**
     * `[\b]`,
     * Matches a backspace (U+0008).
     *
     * @see [backspace](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-backspace)
     */
    static get backspace(): string;
    /**
     * `\b`
     * Matches a word boundary.
     *
     * @see [word boundary](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-word-boundary)
     */
    static get wordBoundary(): string;
    /**
     * `\B`, Matches a non-word boundary.
     *
     * @see [non word boundary](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-non-word-boundary)
     */
    static get nonWordBoundary(): string;
    /**
     * `\cX`
     * Matches a control character in a string.
     *
     * @param X a character ranging from A to Z.
     *
     * @see [control](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-control)
     */
    static controlCharacter(X: string): string;
    /**
     * `\d`, Matches a digit character. Equivalent to `[0 - 9]`.
     *
     * @see [digit](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-digit)
     */
    static get digit(): string;
    /**
     * `\D`, Matches a non-digit character. Equivalent to `[^ 0 - 9]`.
     *
     * @see [non digit](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-non-digit)
     */
    static get nonDigit(): string;
    /**
     * `\f`,
     * Matches a form feed (U+000C).
     *
     * @see [form-feed](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-form-feed)
     */
    static get formfeed(): string;
    /**
     * `\n`,
     * Matches a line feed (U+000A).
     *
     * @see [](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-line-feed)
     */
    static get linefeed(): string;
    /**
     * `\r`,
     * Matches a carriage return (U+000D).
     *
     * @see [](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-carriage-return)
     */
    static get carriageReturn(): string;
    /**
     * `\s`,
     * Matches a white space character, including space, tab, form feed, line feed.
     *
     * @see [white space](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-white-space)
     */
    static get whitespace(): string;
    /**
     * `\S`,
     * Matches a character other than white space.
     *
     * @see [non white space](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-non-white-space)
     */
    static get nonWhitespace(): string;
    /**
     * `\t`,
     * Matches a tab (U+0009).
     *
     * @see [tab](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-tab)
     */
    static get tab(): string;
    /**
     * `\v`,
     * Matches a vertical tab (U+000B).
     *
     * @see [vertical tab](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-vertical-tab)
     */
    static get verticalTab(): string;
    /**
     * `\w`,
     * Matches any alphanumeric character including the underscore.
     *
     * @see [word](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-word)
     */
    static get alphanumeric(): string;
    /**
     * `\W`,
     * Matches any non-word character.
     *
     * @see [non word](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-non-word)
     */
    static get nonWord(): string;
    /**
     * `\n`,
     * Where `n` is a positive integer,
     * a back reference to the last substring matching the `n` parenthetical
     * in the regular expression (counting left parentheses).
     *
     * @see [backreference](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-backreference)
     */
    static backreference(n: number): string;
    /**
     * `\0`, Matches a NULL (U+0000) character.
     *
     * @see [null](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-null)
     */
    static get null(): string;
    /**
     * `\xhh`,
     * Matches the character with the code `hh`.
     * @param hh two hexadecimal digits
     *
     * @see [hex escape](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-hex-escape)
     */
    static hex(hh: string): string;
    /**
     * `\uhhhh`
     * Matches the character with the code `hhhh`.
     * @param hhhh four hexadecimal digits
     *
     * @see [unicode-escape](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-unicode-escape)
     */
    static unicode(hhhh: string): string;
    /**
     * `\u{hhhh} `
     * (only when u flag is set)
     * Matches the character with the Unicode value hhhh (hexadecimal digits).
     * @param hhhh four hexadecimal digits
     *
     * @see [unicode-escape-es6](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#special-unicode-escape-es6)
     */
    static unicodeU(hhhh: string): string;
    /**
     * `g`,
     * Global search.
     */
    static get globalSearchFlag(): string;
    /**
     * `i`,
     * Case-insensitive search.
     */
    static get caseInsensitiveSearchFlag(): string;
    /**
     * `n`,
     * Multi-line search.
     */
    static get multipleLineSearchFlag(): string;
    /**
     * `s`,
     * Allows . to match newline characters.
     */
    static get dotIsNewLineFlag(): string;
    /**
     * `u`,
     * "unicode"; treat a pattern as a sequence of unicode code points.
     */
    static get unicodeFlag(): string;
    /**
     * `y`,
     * Perform a "sticky" search that matches starting at the current position in the target string.
     *
     * @see [sticky](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/sticky)
     */
    static get strickySearchFlag(): string;
}