import type { EventSchema, EventSchemaElement } from "./types";
/** An event schema compiled to instructions, indexed by program counter. */
export type EventSchemaProgram = Readonly<{
    /** The instructions. */
    code: readonly Instruction[];
    /** The program counter a message starts at. */
    start: number;
    /** The segment IDs the `segment` instructions consume. */
    segmentIds: ReadonlySet<string>;
}>;
/**
 * One instruction of a program, discriminated by `op`. `next` and `targets`
 * are program counters.
 */
export type Instruction = Readonly<{
    op: "segment";
    id: string;
    next: number;
}> | Readonly<{
    op: "any";
    next: number;
}> | Readonly<{
    op: "z";
    next: number;
}> | Readonly<{
    op: "split";
    targets: readonly number[];
}> | Readonly<{
    op: "open";
    id: string;
    name: string;
    next: number;
}> | Readonly<{
    op: "close";
    next: number;
}> | Readonly<{
    op: "match";
}>;
/** The segment ID that matches any segment in a schema. */
export declare const ANY_SEGMENT = "Hxx";
/** The segment ID that matches any Z-segment in a schema. */
export declare const ANY_Z_SEGMENT = "anyZSegment";
/** The prefix HL7v2 reserves for locally defined segment IDs. */
export declare const Z_SEGMENT_PREFIX = "Z";
/**
 * Compiles `schema` into the program `runner()` runs.
 *
 * The program prefers, in order: entering an optional element over skipping
 * it, repeating an element over leaving it, and earlier choice alternatives
 * over later ones. Neither `start` nor any instruction targets a split with a
 * single target.
 *
 * @throws {Error} When `schema` has no elements, a segment has no name, a
 *   group has no ID, no name, or no elements, a choice has no alternatives,
 *   or a choice alternative can match no segment.
 */
export declare function compile(schema: EventSchema): EventSchemaProgram;
/**
 * The program `compile()` builds for `schema`, compiled on its first call and
 * kept for the object. `schema` MUST NOT change after its first call.
 *
 * @throws {Error} As `compile()`.
 */
export declare const compileOnce: (arg: Readonly<{
    $schema?: string;
    id: string;
    elements: readonly EventSchemaElement[];
}>) => Readonly<{
    /** The instructions. */
    code: readonly Instruction[];
    /** The program counter a message starts at. */
    start: number;
    /** The segment IDs the `segment` instructions consume. */
    segmentIds: ReadonlySet<string>;
}>;
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