/**
 * Replace the interiors of shell strings, parameter expansions, command
 * substitutions, and arithmetic expansions with spaces so regex-based rules
 * can operate on "bare shell code" without false positives from characters
 * that appear inside `$'...'`, `'...'`, `"..."`, `` `...` ``, `${...}`,
 * `$(...)`, `$((...))`, or trailing `# ...` comments.
 *
 * The returned string has the same length as the input so that indices
 * produced by matches on the masked line are valid indices in the original.
 *
 * Only *interior* characters are masked to spaces; structural delimiters
 * (`'`, `"`, `` ` ``, `$`, `(`, `)`, `{`, `}`) are preserved so that rules
 * can still reason about whether a token sits next to a string boundary —
 * e.g. `"$var"]` still reports the `"` as the character preceding `]`.
 */
export declare function maskShellStrings(line: string): string;
/**
 * Track heredoc start and end within a line-by-line scan. Returns the
 * delimiter recognised at this line, or `null` if this line does not start a
 * heredoc. The caller tracks state by flipping a boolean when
 * `heredocDelimiter` returns non-null, and clearing it when the delimiter
 * matches a subsequent line's trimmed content.
 */
export declare function heredocDelimiter(line: string): string | null;