import { Grammar } from "./cfg.js";
import { GrammarSymbols, Sym } from "./grammar_symbols.js";
export declare const enum ExprKind {
    SEQ = 0,
    OR = 1,
    OPT = 2,
    STAR = 3,
    PLUS = 4
}
export type Expr = Sym | {
    kind: ExprKind;
    params: Expr[];
};
export type ExprGrammar = {
    start: Sym;
    rules: {
        lhs: Sym;
        rhs: Expr;
    }[];
    distinct?: Sym[][];
    empty?: [Sym, Sym][];
    final?: Sym[];
};
export declare function cloneExpr(expr: Expr): Expr;
export declare function cloneExprGrammar(grammar: ExprGrammar): ExprGrammar;
export declare function rule(lhs: Sym, ...rhs: Expr[]): {
    lhs: Sym;
    rhs: Expr;
};
export declare function seq(...exprs: Expr[]): Expr;
export declare function or(...exprs: Expr[]): Expr;
export declare function opt(...exprs: Expr[]): Expr;
export declare function star(...exprs: Expr[]): Expr;
export declare function plus(...exprs: Expr[]): Expr;
export declare function printExpr(expr: Expr): string;
export declare function convertExprGrammar(exprGrammar: ExprGrammar, prefix_nonterminals?: string): {
    symbols: GrammarSymbols;
    grammar: Grammar;
};