/**
 * Shared low-level scanning helpers: source normalization, line classification,
 * escape handling, and URL scanning. Pure functions, no AST/JSX dependency.
 */
import type { HeadingLevel, TableAlign } from '../ast.js';
/**
 * Normalize source for uniform parsing: CRLF/CR → LF, and expand leading tabs
 * to four spaces so indentation logic is consistent. Tabs after the first
 * non-space content are left alone (they only matter for block indentation).
 */
export declare function normalize(src: string): string;
/** Count leading spaces (indentation) of a line. */
export declare function indentOf(line: string): number;
/** True when a line is blank (empty or whitespace-only). */
export declare function isBlank(line: string): boolean;
export interface FenceInfo {
    /** The fence character: '`' or '~'. */
    char: string;
    /** Length of the fence run (≥ 3). */
    length: number;
    /** Indentation of the fence (stripped from content lines). */
    indent: number;
    /** Trimmed info string (language) after the opening fence, if any. */
    info: string;
}
/** Match an opening (or closing) fenced-code-block marker. */
export declare function matchFence(line: string): FenceInfo | null;
/** True when `line` closes a fence opened by `open`. */
export declare function isFenceClose(line: string, open: FenceInfo): boolean;
/** Match an ATX heading (`#`..`######`). Returns level + text, or null. */
export declare function matchHeading(line: string): {
    level: HeadingLevel;
    text: string;
} | null;
/** Match a thematic break (`---`, `***`, `___`, optionally spaced). */
export declare function isThematicBreak(line: string): boolean;
export interface ListMarkerInfo {
    ordered: boolean;
    /** Start number (ordered) or 1 (unordered). */
    start: number;
    /** The bullet/delimiter char: '-', '*', '+', '.', or ')'. */
    delimiter: string;
    /** Column where the item content begins (used for continuation indent). */
    contentIndent: number;
    /** Indentation of the marker itself. */
    markerIndent: number;
    /** The content following the marker on the same line. */
    content: string;
}
/** Match a list-item marker (`- `, `* `, `+ `, `1. `, `1) `). */
export declare function matchListMarker(line: string): ListMarkerInfo | null;
/** Match an empty list item (`-` / `1.` with nothing after). */
export declare function matchEmptyListMarker(line: string): ListMarkerInfo | null;
/**
 * Parse a GFM table delimiter row (`| --- | :--: | --: |`) into per-column
 * alignment, or return null if the line is not a valid delimiter row.
 */
export declare function matchTableDelimiter(line: string): (TableAlign | null)[] | null;
/** Split a table row into raw cell strings, honoring `\|` escapes. */
export declare function splitTableRow(line: string): string[];
/** True when `ch` is a backslash-escapable punctuation character. */
export declare function isEscapable(ch: string): boolean;
/**
 * Return a link href if it is safe to expose to handlers, else `'#'`. Blocks
 * `javascript:`/`data:` and other unexpected schemes. Relative/anchor links and
 * the recognized safe schemes pass through unchanged.
 */
export declare function sanitizeHref(href: string): string;
/** Trailing punctuation trimmed from bare-URL autolinks (GFM behavior). */
export declare function trimAutolinkTail(url: string): {
    url: string;
    tail: string;
};