export type RepeatOperator = "*" | "?" | "+";
export type PositionNode = Literal | Tag | EndMarker;
export type ExpressionNode = Alternation | Concatenation | Repeat | Literal | Tag | EndMarker | Variable;
/**
 * Base AST node
 */
export declare class Node {
    readonly followpos: Set<PositionNode>;
    constructor();
    calcFollowpos(): void;
}
/**
 * Represents a variable reference
 */
export declare class Variable extends Node {
    readonly name: string;
    constructor(name: string);
    get nullable(): boolean;
    get firstpos(): Set<PositionNode>;
    get lastpos(): Set<PositionNode>;
    copy(): Variable;
}
/**
 * Represents a comment
 */
export declare class Comment extends Node {
    readonly value: string;
    constructor(value: string);
}
/**
 * Represents an assignment statement.
 * e.g. `variable = expression;`
 */
export declare class Assignment extends Node {
    readonly variable: Variable;
    expression: ExpressionNode;
    constructor(variable: Variable, expression: ExpressionNode);
}
/**
 * Represents an alternation.
 * e.g. `a | b`
 */
export declare class Alternation extends Node {
    readonly a: ExpressionNode;
    readonly b: ExpressionNode;
    constructor(a: ExpressionNode, b: ExpressionNode);
    get nullable(): boolean;
    get firstpos(): Set<PositionNode>;
    get lastpos(): Set<PositionNode>;
    copy(): Alternation;
}
/**
 * Represents a concatenation, or chain.
 * e.g. `a b c`
 */
export declare class Concatenation extends Node {
    readonly a: ExpressionNode;
    readonly b: ExpressionNode;
    constructor(a: ExpressionNode, b: ExpressionNode);
    get nullable(): boolean;
    get firstpos(): Set<PositionNode>;
    get lastpos(): Set<PositionNode>;
    calcFollowpos(): void;
    copy(): Concatenation;
}
/**
 * Represents a repetition.
 * e.g. `a+`, `b*`, or `c?`
 */
export declare class Repeat extends Node {
    readonly expression: ExpressionNode;
    readonly op: RepeatOperator;
    constructor(expression: ExpressionNode, op: RepeatOperator);
    get nullable(): boolean;
    get firstpos(): Set<PositionNode>;
    get lastpos(): Set<PositionNode>;
    calcFollowpos(): void;
    copy(): Repeat;
}
/** Builds a repetition expression with specified min/max bounds. */
export declare function buildRepetition(expression: ExpressionNode, min?: number, max?: number): ExpressionNode;
/**
 * Base class for leaf nodes
 */
declare class Leaf extends Node {
    copy(): this;
    get nullable(): boolean;
    get firstpos(): Set<PositionNode>;
    get lastpos(): Set<PositionNode>;
}
/**
 * Represents a literal value, e.g. a number
 */
export declare class Literal extends Leaf {
    readonly value: number;
    constructor(value: number);
    copy(): this;
}
/**
 * Marks the end of an expression
 */
export declare class EndMarker extends Leaf {
}
/**
 * Represents a tag
 * e.g. `a:(a b)`
 */
export declare class Tag extends Leaf {
    readonly name: string;
    constructor(name: string);
    get nullable(): boolean;
    copy(): this;
}
export {};