/**
* @license Copyright (c) 2003-2026, CKSource Holding sp. z o.o. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
*/
/**
* @module engine/model/schema
*/
import { ModelElement } from "./element.js";
import { ModelPosition } from "./position.js";
import { ModelRange } from "./range.js";
import { type ModelDocumentFragment } from "./documentfragment.js";
import { type ModelDocumentSelection } from "./documentselection.js";
import { type ModelItem } from "./item.js";
import { type ModelNode } from "./node.js";
import { type ModelSelection } from "./selection.js";
import { type ModelWriter } from "./writer.js";
import { type ObservableMixinConstructor } from "@ckeditor/ckeditor5-utils";
declare const ModelSchemaBase: ObservableMixinConstructor;
/**
* The model's schema. It defines the allowed and disallowed structures of nodes as well as nodes' attributes.
* The schema is usually defined by the features and based on them, the editing framework and features
* make decisions on how to change and process the model.
*
* The instance of schema is available in {@link module:engine/model/model~Model#schema `editor.model.schema`}.
*
* Read more about the schema in:
*
* * The {@glink framework/architecture/editing-engine#schema schema section} of the
* {@glink framework/architecture/editing-engine Introduction to the Editing engine architecture} guide.
* * The {@glink framework/deep-dive/schema Schema deep-dive} guide.
*/
export declare class ModelSchema extends ModelSchemaBase {
	private readonly _sourceDefinitions;
	/**
	* A dictionary containing attribute properties.
	*/
	private readonly _attributeProperties;
	/**
	* Stores additional callbacks registered for schema items, which are evaluated when {@link ~ModelSchema#checkChild} is called.
	*
	* Keys are schema item names for which the callbacks are registered. Values are arrays with the callbacks.
	*
	* Some checks are added under {@link ~ModelSchema#_genericCheckSymbol} key, these are
	* evaluated for every {@link ~ModelSchema#checkChild} call.
	*/
	private readonly _customChildChecks;
	/**
	* Stores additional callbacks registered for attribute names, which are evaluated when {@link ~ModelSchema#checkAttribute} is called.
	*
	* Keys are schema attribute names for which the callbacks are registered. Values are arrays with the callbacks.
	*
	* Some checks are added under {@link ~ModelSchema#_genericCheckSymbol} key, these are evaluated for every
	* {@link ~ModelSchema#checkAttribute} call.
	*/
	private readonly _customAttributeChecks;
	private readonly _genericCheckSymbol;
	private _compiledDefinitions?;
	/**
	* Creates a schema instance.
	*/
	constructor();
	/**
	* Registers a schema item. Can only be called once for every item name.
	*
	* ```ts
	* schema.register( 'paragraph', {
	* 	inheritAllFrom: '$block'
	* } );
	* ```
	*/
	register(itemName: string, definition?: ModelSchemaItemDefinition): void;
	/**
	* Extends a {@link #register registered} item's definition.
	*
	* Extending properties such as `allowIn` will add more items to the existing properties,
	* while redefining properties such as `isBlock` will override the previously defined ones.
	*
	* ```ts
	* schema.register( 'foo', {
	* 	allowIn: '$root',
	* 	isBlock: true;
	* } );
	* schema.extend( 'foo', {
	* 	allowIn: 'blockQuote',
	* 	isBlock: false
	* } );
	*
	* schema.getDefinition( 'foo' );
	* //	{
	* //		allowIn: [ '$root', 'blockQuote' ],
	* // 		isBlock: false
	* //	}
	* ```
	*/
	extend(itemName: string, definition: ModelSchemaItemDefinition): void;
	/**
	* Returns data of all registered items.
	*
	* This method should normally be used for reflection purposes (e.g. defining a clone of a certain element,
	* checking a list of all block elements, etc).
	* Use specific methods (such as {@link #checkChild `checkChild()`} or {@link #isLimit `isLimit()`})
	* in other cases.
	*/
	getDefinitions(): Record<string, ModelSchemaCompiledItemDefinition>;
	/**
	* Returns a definition of the given item or `undefined` if an item is not registered.
	*
	* This method should normally be used for reflection purposes (e.g. defining a clone of a certain element,
	* checking a list of all block elements, etc).
	* Use specific methods (such as {@link #checkChild `checkChild()`} or {@link #isLimit `isLimit()`})
	* in other cases.
	*/
	getDefinition(item: string | ModelItem | ModelDocumentFragment | ModelSchemaContextItem): ModelSchemaCompiledItemDefinition | undefined;
	/**
	* Returns `true` if the given item is registered in the schema.
	*
	* ```ts
	* schema.isRegistered( 'paragraph' ); // -> true
	* schema.isRegistered( editor.model.document.getRoot() ); // -> true
	* schema.isRegistered( 'foo' ); // -> false
	* ```
	*/
	isRegistered(item: string | ModelItem | ModelDocumentFragment | ModelSchemaContextItem): boolean;
	/**
	* Returns `true` if the given item is defined to be
	* a block by the {@link module:engine/model/schema~ModelSchemaItemDefinition}'s `isBlock` property.
	*
	* ```ts
	* schema.isBlock( 'paragraph' ); // -> true
	* schema.isBlock( '$root' ); // -> false
	*
	* const paragraphElement = writer.createElement( 'paragraph' );
	* schema.isBlock( paragraphElement ); // -> true
	* ```
	*
	* See the {@glink framework/deep-dive/schema#block-elements Block elements} section of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide for more details.
	*/
	isBlock(item: string | ModelItem | ModelDocumentFragment | ModelSchemaContextItem): boolean;
	/**
	* Returns `true` if the given item should be treated as a limit element.
	*
	* It considers an item to be a limit element if its
	* {@link module:engine/model/schema~ModelSchemaItemDefinition}'s
	* {@link module:engine/model/schema~ModelSchemaItemDefinition#isLimit `isLimit`} or
	* {@link module:engine/model/schema~ModelSchemaItemDefinition#isObject `isObject`} property
	* was set to `true`.
	*
	* ```ts
	* schema.isLimit( 'paragraph' ); // -> false
	* schema.isLimit( '$root' ); // -> true
	* schema.isLimit( editor.model.document.getRoot() ); // -> true
	* schema.isLimit( 'imageBlock' ); // -> true
	* ```
	*
	* See the {@glink framework/deep-dive/schema#limit-elements Limit elements} section of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide for more details.
	*/
	isLimit(item: string | ModelItem | ModelDocumentFragment | ModelSchemaContextItem): boolean;
	/**
	* Returns `true` if the given item should be treated as an object element.
	*
	* It considers an item to be an object element if its
	* {@link module:engine/model/schema~ModelSchemaItemDefinition}'s
	* {@link module:engine/model/schema~ModelSchemaItemDefinition#isObject `isObject`} property
	* was set to `true`.
	*
	* ```ts
	* schema.isObject( 'paragraph' ); // -> false
	* schema.isObject( 'imageBlock' ); // -> true
	*
	* const imageElement = writer.createElement( 'imageBlock' );
	* schema.isObject( imageElement ); // -> true
	* ```
	*
	* See the {@glink framework/deep-dive/schema#object-elements Object elements} section of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide for more details.
	*/
	isObject(item: string | ModelItem | ModelDocumentFragment | ModelSchemaContextItem): boolean;
	/**
	* Returns `true` if the given item is defined to be
	* an inline element by the {@link module:engine/model/schema~ModelSchemaItemDefinition}'s `isInline` property.
	*
	* ```ts
	* schema.isInline( 'paragraph' ); // -> false
	* schema.isInline( 'softBreak' ); // -> true
	*
	* const text = writer.createText( 'foo' );
	* schema.isInline( text ); // -> true
	* ```
	*
	* See the {@glink framework/deep-dive/schema#inline-elements Inline elements} section of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide for more details.
	*/
	isInline(item: string | ModelItem | ModelDocumentFragment | ModelSchemaContextItem): boolean;
	/**
	* Returns `true` if the given item is defined to be
	* a selectable element by the {@link module:engine/model/schema~ModelSchemaItemDefinition}'s `isSelectable` property.
	*
	* ```ts
	* schema.isSelectable( 'paragraph' ); // -> false
	* schema.isSelectable( 'heading1' ); // -> false
	* schema.isSelectable( 'imageBlock' ); // -> true
	* schema.isSelectable( 'tableCell' ); // -> true
	*
	* const text = writer.createText( 'foo' );
	* schema.isSelectable( text ); // -> false
	* ```
	*
	* See the {@glink framework/deep-dive/schema#selectable-elements Selectable elements section} of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide for more details.
	*/
	isSelectable(item: string | ModelItem | ModelDocumentFragment | ModelSchemaContextItem): boolean;
	/**
	* Returns `true` if the given item is defined to be
	* a content by the {@link module:engine/model/schema~ModelSchemaItemDefinition}'s `isContent` property.
	*
	* ```ts
	* schema.isContent( 'paragraph' ); // -> false
	* schema.isContent( 'heading1' ); // -> false
	* schema.isContent( 'imageBlock' ); // -> true
	* schema.isContent( 'horizontalLine' ); // -> true
	*
	* const text = writer.createText( 'foo' );
	* schema.isContent( text ); // -> true
	* ```
	*
	* See the {@glink framework/deep-dive/schema#content-elements Content elements section} of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide for more details.
	*/
	isContent(item: string | ModelItem | ModelDocumentFragment | ModelSchemaContextItem): boolean;
	/**
	* Checks whether the given node can be a child of the given context.
	*
	* ```ts
	* schema.checkChild( model.document.getRoot(), paragraph ); // -> false
	*
	* schema.register( 'paragraph', {
	* 	allowIn: '$root'
	* } );
	*
	* schema.checkChild( model.document.getRoot(), paragraph ); // -> true
	* ```
	*
	* Both {@link module:engine/model/schema~ModelSchema#addChildCheck callback checks} and declarative rules (added when
	* {@link module:engine/model/schema~ModelSchema#register registering} and
	* {@link module:engine/model/schema~ModelSchema#extend extending} items)
	* are evaluated when this method is called.
	*
	* Note that callback checks have bigger priority than declarative rules checks and may overwrite them.
	*
	* Note that when verifying whether the given node can be a child of the given context, the schema also verifies the entire
	* context &ndash; from its root to its last element. Therefore, it is possible for `checkChild()` to return `false` even though
	* the `context` last element can contain the checked child. It happens if one of the `context` elements does not allow its child.
	* When `context` is verified, {@link module:engine/model/schema~ModelSchema#addChildCheck custom checks} are considered as well.
	*
	* @fires checkChild
	* @param context The context in which the child will be checked.
	* @param def The child to check.
	*/
	checkChild(context: ModelSchemaContextDefinition, def: string | ModelNode | ModelDocumentFragment): boolean;
	/**
	* Checks whether the given attribute can be applied in the given context (on the last item of the context).
	*
	* ```ts
	* schema.checkAttribute( textNode, 'bold' ); // -> false
	*
	* schema.extend( '$text', {
	* 	allowAttributes: 'bold'
	* } );
	*
	* schema.checkAttribute( textNode, 'bold' ); // -> true
	* ```
	*
	* Both {@link module:engine/model/schema~ModelSchema#addAttributeCheck callback checks} and declarative rules (added when
	* {@link module:engine/model/schema~ModelSchema#register registering} and
	* {@link module:engine/model/schema~ModelSchema#extend extending} items)
	* are evaluated when this method is called.
	*
	* Note that callback checks have bigger priority than declarative rules checks and may overwrite them.
	*
	* @fires checkAttribute
	* @param context The context in which the attribute will be checked.
	* @param attributeName Name of attribute to check in the given context.
	*/
	checkAttribute(context: ModelSchemaContextDefinition, attributeName: string): boolean;
	checkMerge(position: ModelPosition): boolean;
	checkMerge(baseElement: ModelElement, elementToMerge: ModelElement): boolean;
	/**
	* Allows registering a callback to the {@link #checkChild} method calls.
	*
	* Callbacks allow you to implement rules which are not otherwise possible to achieve
	* by using the declarative API of {@link module:engine/model/schema~ModelSchemaItemDefinition}.
	*
	* Note that callback checks have bigger priority than declarative rules checks and may overwrite them.
	*
	* For example, by using this method you can disallow elements in specific contexts:
	*
	* ```ts
	* // Disallow `heading1` inside a `blockQuote` that is inside a table.
	* schema.addChildCheck( ( context, childDefinition ) => {
	* 	if ( context.endsWith( 'tableCell blockQuote' ) ) {
	* 		return false;
	* 	}
	* }, 'heading1' );
	* ```
	*
	* You can skip the optional `itemName` parameter to evaluate the callback for every `checkChild()` call.
	*
	* ```ts
	* // Inside specific custom element, allow only children, which allows for a specific attribute.
	* schema.addChildCheck( ( context, childDefinition ) => {
	* 	if ( context.endsWith( 'myElement' ) ) {
	* 		return childDefinition.allowAttributes.includes( 'myAttribute' );
	* 	}
	* } );
	* ```
	*
	* Please note that the generic callbacks may affect the editor performance and should be avoided if possible.
	*
	* When one of the callbacks makes a decision (returns `true` or `false`) the processing is finished and other callbacks are not fired.
	* Callbacks are fired in the order they were added, however generic callbacks are fired before callbacks added for a specified item.
	*
	* You can also use `checkChild` event, if you need even better control. The result from the example above could also be
	* achieved with following event callback:
	*
	* ```ts
	* schema.on( 'checkChild', ( evt, args ) => {
	* 	const context = args[ 0 ];
	* 	const childDefinition = args[ 1 ];
	*
	* 	if ( context.endsWith( 'myElement' ) ) {
	* 		// Prevent next listeners from being called.
	* 		evt.stop();
	* 		// Set the `checkChild()` return value.
	* 		evt.return = childDefinition.allowAttributes.includes( 'myAttribute' );
	* 	}
	* }, { priority: 'high' } );
	* ```
	*
	* Note that the callback checks and declarative rules checks are processed on `normal` priority.
	*
	* Adding callbacks this way can also negatively impact editor performance.
	*
	* @param callback The callback to be called. It is called with two parameters:
	* {@link module:engine/model/schema~ModelSchemaContext} (context) instance and
	* {@link module:engine/model/schema~ModelSchemaCompiledItemDefinition} (definition). The callback may return `true/false` to
	* override `checkChild()`'s return value. If it does not return a boolean value, the default algorithm (or other callbacks) will define
	* `checkChild()`'s return value.
	* @param itemName Name of the schema item for which the callback is registered. If specified, the callback will be run only for
	* `checkChild()` calls which `def` parameter matches the `itemName`. Otherwise, the callback will run for every `checkChild` call.
	*/
	addChildCheck(callback: ModelSchemaChildCheckCallback, itemName?: string): void;
	/**
	* Allows registering a callback to the {@link #checkAttribute} method calls.
	*
	* Callbacks allow you to implement rules which are not otherwise possible to achieve
	* by using the declarative API of {@link module:engine/model/schema~ModelSchemaItemDefinition}.
	*
	* Note that callback checks have bigger priority than declarative rules checks and may overwrite them.
	*
	* For example, by using this method you can disallow setting attributes on nodes in specific contexts:
	*
	* ```ts
	* // Disallow setting `bold` on text inside `heading1` element:
	* schema.addAttributeCheck( context => {
	* 	if ( context.endsWith( 'heading1 $text' ) ) {
	* 		return false;
	* 	}
	* }, 'bold' );
	* ```
	*
	* You can skip the optional `attributeName` parameter to evaluate the callback for every `checkAttribute()` call.
	*
	* ```ts
	* // Disallow formatting attributes on text inside custom `myTitle` element:
	* schema.addAttributeCheck( ( context, attributeName ) => {
	* 	if ( context.endsWith( 'myTitle $text' ) && schema.getAttributeProperties( attributeName ).isFormatting ) {
	* 		return false;
	* 	}
	* } );
	* ```
	*
	* Please note that the generic callbacks may affect the editor performance and should be avoided if possible.
	*
	* When one of the callbacks makes a decision (returns `true` or `false`) the processing is finished and other callbacks are not fired.
	* Callbacks are fired in the order they were added, however generic callbacks are fired before callbacks added for a specified item.
	*
	* You can also use {@link #event:checkAttribute} event, if you need even better control. The result from the example above could also
	* be achieved with following event callback:
	*
	* ```ts
	* schema.on( 'checkAttribute', ( evt, args ) => {
	* 	const context = args[ 0 ];
	* 	const attributeName = args[ 1 ];
	*
	* 	if ( context.endsWith( 'myTitle $text' ) && schema.getAttributeProperties( attributeName ).isFormatting ) {
	* 		// Prevent next listeners from being called.
	* 		evt.stop();
	* 		// Set the `checkAttribute()` return value.
	* 		evt.return = false;
	* 	}
	* }, { priority: 'high' } );
	* ```
	*
	* Note that the callback checks and declarative rules checks are processed on `normal` priority.
	*
	* Adding callbacks this way can also negatively impact editor performance.
	*
	* @param callback The callback to be called. It is called with two parameters:
	* {@link module:engine/model/schema~ModelSchemaContext `context`} and attribute name. The callback may return `true` or `false`, to
	* override `checkAttribute()`'s return value. If it does not return a boolean value, the default algorithm (or other callbacks)
	* will define `checkAttribute()`'s return value.
	* @param attributeName Name of the attribute for which the callback is registered. If specified, the callback will be run only for
	* `checkAttribute()` calls with matching `attributeName`. Otherwise, the callback will run for every `checkAttribute()` call.
	*/
	addAttributeCheck(callback: ModelSchemaAttributeCheckCallback, attributeName?: string): void;
	/**
	* This method allows assigning additional metadata to the model attributes. For example,
	* {@link module:engine/model/schema~ModelAttributeProperties `AttributeProperties#isFormatting` property} is
	* used to mark formatting attributes (like `bold` or `italic`).
	*
	* ```ts
	* // Mark bold as a formatting attribute.
	* schema.setAttributeProperties( 'bold', {
	* 	isFormatting: true
	* } );
	*
	* // Override code not to be considered a formatting markup.
	* schema.setAttributeProperties( 'code', {
	* 	isFormatting: false
	* } );
	* ```
	*
	* Properties are not limited to members defined in the
	* {@link module:engine/model/schema~ModelAttributeProperties `AttributeProperties` type} and you can also use custom properties:
	*
	* ```ts
	* schema.setAttributeProperties( 'blockQuote', {
	* 	customProperty: 'value'
	* } );
	* ```
	*
	* Subsequent calls with the same attribute will extend its custom properties:
	*
	* ```ts
	* schema.setAttributeProperties( 'blockQuote', {
	* 	one: 1
	* } );
	*
	* schema.setAttributeProperties( 'blockQuote', {
	* 	two: 2
	* } );
	*
	* console.log( schema.getAttributeProperties( 'blockQuote' ) );
	* // Logs: { one: 1, two: 2 }
	* ```
	*
	* @param attributeName A name of the attribute to receive the properties.
	* @param properties A dictionary of properties.
	*/
	setAttributeProperties(attributeName: string, properties: ModelAttributeProperties): void;
	/**
	* Returns properties associated with a given model attribute. See {@link #setAttributeProperties `setAttributeProperties()`}.
	*
	* @param attributeName A name of the attribute.
	*/
	getAttributeProperties(attributeName: string): ModelAttributeProperties;
	/**
	* Returns the lowest {@link module:engine/model/schema~ModelSchema#isLimit limit element} containing the entire
	* selection/range/position or the root otherwise.
	*
	* @param selectionOrRangeOrPosition The selection/range/position to check.
	* @returns The lowest limit element containing the entire `selectionOrRangeOrPosition`.
	*/
	getLimitElement(selectionOrRangeOrPosition: ModelSelection | ModelDocumentSelection | ModelRange | ModelPosition): ModelElement;
	/**
	* Checks whether the attribute is allowed in selection:
	*
	* * if the selection is not collapsed, then checks if the attribute is allowed on any of nodes in that range,
	* * if the selection is collapsed, then checks if on the selection position there's a text with the
	* specified attribute allowed.
	*
	* @param selection Selection which will be checked.
	* @param attribute The name of the attribute to check.
	*/
	checkAttributeInSelection(selection: ModelSelection | ModelDocumentSelection, attribute: string): boolean;
	/**
	* Transforms the given set of ranges into a set of ranges where the given attribute is allowed (and can be applied).
	*
	* @param ranges Ranges to be validated.
	* @param attribute The name of the attribute to check.
	* @param options Optional configuration.
	* @param options.includeEmptyRanges When `true`, empty ranges that allow the attribute are also included
	* in the returned ranges.
	* @returns Ranges in which the attribute is allowed.
	*/
	getValidRanges(ranges: Iterable<ModelRange>, attribute: string, options?: {
		includeEmptyRanges?: boolean;
	}): IterableIterator<ModelRange>;
	/**
	* Basing on given `position`, finds and returns a {@link module:engine/model/range~ModelRange range} which is
	* nearest to that `position` and is a correct range for selection.
	*
	* The correct selection range might be collapsed when it is located in a position where the text node can be placed.
	* Non-collapsed range is returned when selection can be placed around element marked as an "object" in
	* the {@link module:engine/model/schema~ModelSchema schema}.
	*
	* Direction of searching for the nearest correct selection range can be specified as:
	*
	* * `both` - searching will be performed in both ways,
	* * `forward` - searching will be performed only forward,
	* * `backward` - searching will be performed only backward.
	*
	* When valid selection range cannot be found, `null` is returned.
	*
	* @param position Reference position where new selection range should be looked for.
	* @param direction Search direction.
	* @returns Nearest selection range or `null` if one cannot be found.
	*/
	getNearestSelectionRange(position: ModelPosition, direction?: "both" | "forward" | "backward"): ModelRange | null;
	/**
	* Tries to find position ancestors that allow to insert a given node.
	* It starts searching from the given position and goes node by node to the top of the model tree
	* as long as a {@link module:engine/model/schema~ModelSchema#isLimit limit element}, an
	* {@link module:engine/model/schema~ModelSchema#isObject object element} or a topmost ancestor is not reached.
	*
	* @param position The position that the search will start from.
	* @param node The node for which an allowed parent should be found or its name.
	* @returns Allowed parent or null if nothing was found.
	*/
	findAllowedParent(position: ModelPosition, node: ModelNode | string): ModelElement | null;
	/**
	* Sets attributes allowed by the schema on a given node.
	*
	* @param node A node to set attributes on.
	* @param attributes Attributes keys and values.
	* @param writer An instance of the model writer.
	*/
	setAllowedAttributes(node: ModelNode, attributes: Record<string, unknown>, writer: ModelWriter): void;
	/**
	* Removes attributes disallowed by the schema.
	*
	* @param nodes Nodes that will be filtered.
	*/
	removeDisallowedAttributes(nodes: Iterable<ModelNode>, writer: ModelWriter): void;
	/**
	* Gets attributes of a node that have a given property.
	*
	* @param node Node to get attributes from.
	* @param propertyName Name of the property that attribute must have to return it.
	* @param propertyValue Desired value of the property that we want to check.
	* When `undefined` attributes will be returned if they have set a given property no matter what the value is. If specified it will
	* return attributes which given property's value is equal to this parameter.
	* @returns Object with attributes' names as key and attributes' values as value.
	*/
	getAttributesWithProperty(node: ModelNode, propertyName: string, propertyValue: unknown): Record<string, unknown>;
	/**
	* Creates an instance of the schema context.
	*/
	createContext(context: ModelSchemaContextDefinition): ModelSchemaContext;
	private _clearCache;
	private _compile;
	private _checkContextMatch;
	/**
	* Calls child check callbacks to decide whether `def` is allowed in `context`. It uses both generic and specific (defined for `def`
	* item) callbacks. If neither callback makes a decision, `undefined` is returned.
	*
	* Note that the first callback that makes a decision "wins", i.e., if any callback returns `true` or `false`, then the processing
	* is over and that result is returned.
	*/
	private _evaluateChildChecks;
	/**
	* Calls attribute check callbacks to decide whether `attributeName` can be set on the last element of `context`. It uses both
	* generic and specific (defined for `attributeName`) callbacks. If neither callback makes a decision, `undefined` is returned.
	*
	* Note that the first callback that makes a decision "wins", i.e., if any callback returns `true` or `false`, then the processing
	* is over and that result is returned.
	*/
	private _evaluateAttributeChecks;
	/**
	* Takes a flat range and an attribute name. Traverses the range recursively and deeply to find and return all ranges
	* inside the given range on which the attribute can be applied.
	*
	* This is a helper function for {@link ~ModelSchema#getValidRanges}.
	*
	* @param range The range to process.
	* @param attribute The name of the attribute to check.
	* @returns Ranges in which the attribute is allowed.
	*/
	private _getValidRangesForRange;
	/**
	* Returns a model range which is optimal (in terms of UX) for inserting a widget block.
	*
	* For instance, if a selection is in the middle of a paragraph, the collapsed range before this paragraph
	* will be returned so that it is not split. If the selection is at the end of a paragraph,
	* the collapsed range after this paragraph will be returned.
	*
	* Note: If the selection is placed in an empty block, the range in that block will be returned. If that range
	* is then passed to {@link module:engine/model/model~Model#insertContent}, the block will be fully replaced
	* by the inserted widget block.
	*
	* @internal
	* @param selection The selection based on which the insertion position should be calculated.
	* @param place The place where to look for optimal insertion range.
	* The `auto` value will determine itself the best position for insertion.
	* The `before` value will try to find a position before selection.
	* The `after` value will try to find a position after selection.
	* @returns The optimal range.
	*/
	findOptimalInsertionRange(selection: ModelSelection | ModelDocumentSelection, place?: "auto" | "before" | "after"): ModelRange;
}
/**
* Event fired when the {@link ~ModelSchema#checkChild} method is called. It allows plugging in
* additional behavior, for example implementing rules which cannot be defined using the declarative
* {@link module:engine/model/schema~ModelSchemaItemDefinition} interface.
*
* **Note:** The {@link ~ModelSchema#addChildCheck} method is a more handy way to register callbacks. Internally,
* it registers a listener to this event but comes with a simpler API and it is the recommended choice
* in most of the cases.
*
* The {@link ~ModelSchema#checkChild} method fires an event because it is
* {@link module:utils/observablemixin~Observable#decorate decorated} with it. Thanks to that you can
* use this event in various ways, but the most important use case is overriding standard behavior of the
* `checkChild()` method. Let's see a typical listener template:
*
* ```ts
* schema.on( 'checkChild', ( evt, args ) => {
* 	const context = args[ 0 ];
* 	const childDefinition = args[ 1 ];
* }, { priority: 'high' } );
* ```
*
* The listener is added with a `high` priority to be executed before the default method is really called. The `args` callback
* parameter contains arguments passed to `checkChild( context, child )`. However, the `context` parameter is already
* normalized to a {@link module:engine/model/schema~ModelSchemaContext} instance and `child` to a
* {@link module:engine/model/schema~ModelSchemaCompiledItemDefinition} instance, so you do not have to worry about
* the various ways how `context` and `child` may be passed to `checkChild()`.
*
* **Note:** `childDefinition` may be `undefined` if `checkChild()` was called with a non-registered element.
*
* So, in order to implement a rule "disallow `heading1` in `blockQuote`", you can add such a listener:
*
* ```ts
* schema.on( 'checkChild', ( evt, args ) => {
* 	const context = args[ 0 ];
* 	const childDefinition = args[ 1 ];
*
* 	if ( context.endsWith( 'blockQuote' ) && childDefinition && childDefinition.name == 'heading1' ) {
* 		// Prevent next listeners from being called.
* 		evt.stop();
* 		// Set the checkChild()'s return value.
* 		evt.return = false;
* 	}
* }, { priority: 'high' } );
* ```
*
* Allowing elements in specific contexts will be a far less common use case, because it is normally handled by the
* `allowIn` rule from {@link module:engine/model/schema~ModelSchemaItemDefinition}. But if you have a complex scenario
* where `listItem` should be allowed only in element `foo` which must be in element `bar`, then this would be the way:
*
* ```ts
* schema.on( 'checkChild', ( evt, args ) => {
* 	const context = args[ 0 ];
* 	const childDefinition = args[ 1 ];
*
* 	if ( context.endsWith( 'bar foo' ) && childDefinition.name == 'listItem' ) {
* 		// Prevent next listeners from being called.
* 		evt.stop();
* 		// Set the checkChild()'s return value.
* 		evt.return = true;
* 	}
* }, { priority: 'high' } );
* ```
*
* @eventName ~ModelSchema#checkChild
* @param args The `checkChild()`'s arguments.
*/
export type ModelSchemaCheckChildEvent = {
	name: "checkChild";
	args: [[context: ModelSchemaContext, def: ModelSchemaCompiledItemDefinition]];
};
/**
* Event fired when the {@link ~ModelSchema#checkAttribute} method is called. It allows plugging in
* additional behavior, for example implementing rules which cannot be defined using the declarative
* {@link module:engine/model/schema~ModelSchemaItemDefinition} interface.
*
* **Note:** The {@link ~ModelSchema#addAttributeCheck} method is a more handy way to register callbacks. Internally,
* it registers a listener to this event but comes with a simpler API and it is the recommended choice
* in most of the cases.
*
* The {@link ~ModelSchema#checkAttribute} method fires an event because it is
* {@link module:utils/observablemixin~Observable#decorate decorated} with it. Thanks to that you can
* use this event in various ways, but the most important use case is overriding the standard behavior of the
* `checkAttribute()` method. Let's see a typical listener template:
*
* ```ts
* schema.on( 'checkAttribute', ( evt, args ) => {
* 	const context = args[ 0 ];
* 	const attributeName = args[ 1 ];
* }, { priority: 'high' } );
* ```
*
* The listener is added with a `high` priority to be executed before the default method is really called. The `args` callback
* parameter contains arguments passed to `checkAttribute( context, attributeName )`. However, the `context` parameter is already
* normalized to a {@link module:engine/model/schema~ModelSchemaContext} instance, so you do not have to worry about
* the various ways how `context` may be passed to `checkAttribute()`.
*
* So, in order to implement a rule "disallow `bold` in a text which is in a `heading1`, you can add such a listener:
*
* ```ts
* schema.on( 'checkAttribute', ( evt, args ) => {
* 	const context = args[ 0 ];
* 	const attributeName = args[ 1 ];
*
* 	if ( context.endsWith( 'heading1 $text' ) && attributeName == 'bold' ) {
* 		// Prevent next listeners from being called.
* 		evt.stop();
* 		// Set the checkAttribute()'s return value.
* 		evt.return = false;
* 	}
* }, { priority: 'high' } );
* ```
*
* Allowing attributes in specific contexts will be a far less common use case, because it is normally handled by the
* `allowAttributes` rule from {@link module:engine/model/schema~ModelSchemaItemDefinition}. But if you have a complex scenario
* where `bold` should be allowed only in element `foo` which must be in element `bar`, then this would be the way:
*
* ```ts
* schema.on( 'checkAttribute', ( evt, args ) => {
* 	const context = args[ 0 ];
* 	const attributeName = args[ 1 ];
*
* 	if ( context.endsWith( 'bar foo $text' ) && attributeName == 'bold' ) {
* 		// Prevent next listeners from being called.
* 		evt.stop();
* 		// Set the checkAttribute()'s return value.
* 		evt.return = true;
* 	}
* }, { priority: 'high' } );
* ```
*
* @eventName ~ModelSchema#checkAttribute
* @param args The `checkAttribute()`'s arguments.
*/
export type ModelSchemaCheckAttributeEvent = {
	name: "checkAttribute";
	args: [[context: ModelSchemaContext, attributeName: string]];
};
/**
* A definition of a {@link module:engine/model/schema~ModelSchema schema} item.
*
* You can define the following rules:
*
* * {@link ~ModelSchemaItemDefinition#allowIn `allowIn`} &ndash; Defines in which other items this item will be allowed.
* * {@link ~ModelSchemaItemDefinition#allowChildren `allowChildren`} &ndash; Defines which other items are allowed inside this item.
* * {@link ~ModelSchemaItemDefinition#allowAttributes `allowAttributes`} &ndash; Defines allowed attributes of the given item.
* * {@link ~ModelSchemaItemDefinition#disallowIn `disallowIn`} &ndash; Defines in which other items this item will be disallowed.
* * {@link ~ModelSchemaItemDefinition#disallowChildren `disallowChildren`} &ndash; Defines which other items are
* disallowed inside this item.
* * {@link ~ModelSchemaItemDefinition#disallowAttributes `disallowAttributes`} &ndash; Defines disallowed attributes of the given item.
* * {@link ~ModelSchemaItemDefinition#allowContentOf `allowContentOf`} &ndash; Makes this item allow children that are also allowed in the
* specified items. This acknowledges disallow rules.
* * {@link ~ModelSchemaItemDefinition#allowWhere `allowWhere`} &ndash; Makes this item allowed where the specified items are allowed. This
* acknowledges disallow rules.
* * {@link ~ModelSchemaItemDefinition#allowAttributesOf `allowAttributesOf`} &ndash; Inherits attributes from other items.
* This acknowledges disallow rules.
* * {@link ~ModelSchemaItemDefinition#inheritTypesFrom `inheritTypesFrom`} &ndash; Inherits `is*` properties of other items.
* * {@link ~ModelSchemaItemDefinition#inheritAllFrom `inheritAllFrom`} &ndash;
* A shorthand for `allowContentOf`, `allowWhere`, `allowAttributesOf`, `inheritTypesFrom`.
*
* # The `is*` properties
*
* There are a couple commonly used `is*` properties. Their role is to assign additional semantics to schema items.
*
* * {@link ~ModelSchemaItemDefinition#isBlock `isBlock`} &ndash; Whether this item is paragraph-like.
* Generally speaking, content is usually made out of blocks like paragraphs, list items, images, headings, etc.
* * {@link ~ModelSchemaItemDefinition#isInline `isInline`} &ndash; Whether an item is "text-like" and should be treated as an inline node.
* Examples of inline elements: `$text`, `softBreak` (`<br>`), etc.
* * {@link ~ModelSchemaItemDefinition#isLimit `isLimit`} &ndash; It can be understood as whether this element
* should not be split by <kbd>Enter</kbd>. Examples of limit elements: `$root`, table cell, image caption, etc.
* In other words, all actions that happen inside a limit element are limited to its content.
* All objects are treated as limit elements, too.
* * {@link ~ModelSchemaItemDefinition#isObject `isObject`} &ndash; Whether an item is "self-contained" and should be treated as a whole.
* Examples of object elements: `imageBlock`, `table`, `video`, etc. An object is also a limit, so
* {@link module:engine/model/schema~ModelSchema#isLimit `isLimit()`} returns `true` for object elements automatically.
*
* Read more about the meaning of these types in the
* {@glink framework/deep-dive/schema#defining-additional-semantics dedicated section of the Schema deep-dive} guide.
*
* # Generic items
*
* There are several generic items (classes of elements) available: `$root`, `$container`, `$block`, `$blockObject`,
* `$inlineObject`, and `$text`. They are defined as follows:
*
* ```ts
* schema.register( '$root', {
* 	isLimit: true
* } );
*
* schema.register( '$container', {
* 	allowIn: [ '$root', '$container' ]
* } );
*
* schema.register( '$block', {
* 	allowIn: [ '$root', '$container' ],
* 	isBlock: true
* } );
*
* schema.register( '$blockObject', {
* 	allowWhere: '$block',
* 	isBlock: true,
* 	isObject: true
* } );
*
* schema.register( '$inlineObject', {
* 	allowWhere: '$text',
* 	allowAttributesOf: '$text',
* 	isInline: true,
* 	isObject: true
* } );
*
* schema.register( '$text', {
* 	allowIn: '$block',
* 	isInline: true,
* 	isContent: true
* } );
* ```
*
* They reflect typical editor content that is contained within one root, consists of several blocks
* (paragraphs, lists items, headings, images) which, in turn, may contain text inside.
*
* By inheriting from the generic items you can define new items which will get extended by other editor features.
* Read more about generic types in the {@glink framework/deep-dive/schema Schema deep-dive} guide.
*
* # Example definitions
*
* Allow `paragraph` in roots and block quotes:
*
* ```ts
* schema.register( 'paragraph', {
* 	allowIn: [ '$root', 'blockQuote' ],
* 	isBlock: true
* } );
* ```
*
* Allow `paragraph` everywhere where `$block` is allowed (i.e. in `$root`):
*
* ```ts
* schema.register( 'paragraph', {
* 	allowWhere: '$block',
* 	isBlock: true
* } );
* ```
*
* Allow `paragraph` inside a `$root` and allow `$text` as a `paragraph` child:
*
* ```ts
* schema.register( 'paragraph', {
* 	allowIn: '$root',
* 	allowChildren: '$text',
* 	isBlock: true
* } );
* ```
*
* The previous rule can be written in a shorter form using inheritance:
*
* ```ts
* schema.register( 'paragraph', {
* 	inheritAllFrom: '$block'
* } );
* ```
*
* Make `imageBlock` a block object, which is allowed everywhere where `$block` is.
* Also, allow `src` and `alt` attributes in it:
*
* ```ts
* schema.register( 'imageBlock', {
* 	inheritAllFrom: '$blockObject',
* 	allowAttributes: [ 'src', 'alt' ],
* } );
* ```
*
* Make `caption` allowed in `imageBlock` and make it allow all the content of `$block`s (usually, `$text`).
* Also, mark it as a limit element so it cannot be split:
*
* ```ts
* schema.register( 'caption', {
* 	allowIn: 'imageBlock',
* 	allowContentOf: '$block',
* 	isLimit: true
* } );
* ```
*
* Register `inlineImage` as a kind of an inline object but disallow it inside captions:
*
* ```ts
* schema.register( 'imageInline', {
* 	inheritAllFrom: '$inlineObject',
* 	disallowIn: [ 'caption' ]
* } );
* ```
*
* Make `listItem` inherit all from `$block` but also allow additional attributes:
*
* ```ts
* schema.register( 'listItem', {
* 	inheritAllFrom: '$block',
* 	allowAttributes: [ 'listType', 'listIndent' ]
* } );
* ```
*
* Which translates to:
*
* ```ts
* schema.register( 'listItem', {
* 	allowWhere: '$block',
* 	allowContentOf: '$block',
* 	allowAttributesOf: '$block',
* 	inheritTypesFrom: '$block',
* 	allowAttributes: [ 'listType', 'listIndent' ]
* } );
* ```
*
* # Tips
*
* * Check schema definitions of existing features to see how they are defined.
* * If you want to publish your feature so other developers can use it, try to use
* generic items as much as possible.
* * Keep your model clean. Limit it to the actual data and store information in a normalized way.
* * Remember about defining the `is*` properties. They do not affect the allowed structures, but they can
* affect how the editor features treat your elements.
*/
export interface ModelSchemaItemDefinition {
	/**
	* Defines in which other items this item will be allowed.
	*/
	allowIn?: string | Array<string>;
	/**
	* Defines which other items are allowed inside this item.
	*/
	allowChildren?: string | Array<string>;
	/**
	* Defines allowed attributes of the given item.
	*/
	allowAttributes?: string | Array<string>;
	/**
	* Defines in which other items this item will be disallowed. Takes precedence over allow rules.
	*/
	disallowIn?: string | Array<string>;
	/**
	* Defines which other items are disallowed inside this item. Takes precedence over allow rules.
	*/
	disallowChildren?: string | Array<string>;
	/**
	* Defines disallowed attributes for this item. Takes precedence over allow rules.
	*/
	disallowAttributes?: string | Array<string>;
	/**
	* Inherits "allowed children" from other items.
	*
	* Note that the item's "own" rules take precedence over "inherited" rules and can overwrite them.
	*/
	allowContentOf?: string | Array<string>;
	/**
	* Inherits "allowed in" from other items.
	*
	* Note that the item's "own" rules take precedence over "inherited" rules and can overwrite them.
	*/
	allowWhere?: string | Array<string>;
	/**
	* Inherits "allowed attributes" from other items.
	*
	* Note that the item's "own" rules take precedence over "inherited" rules and can overwrite them.
	*/
	allowAttributesOf?: string | Array<string>;
	/**
	* Inherits `is*` properties of other items.
	*
	* Note that the item's "own" rules take precedence over "inherited" rules and can overwrite them.
	*/
	inheritTypesFrom?: string | Array<string>;
	/**
	* A shorthand for `allowContentOf`, `allowWhere`, `allowAttributesOf`, `inheritTypesFrom`.
	*
	* Note that the item's "own" rules take precedence over "inherited" rules and can overwrite them.
	*/
	inheritAllFrom?: string;
	/**
	* Whether this item is paragraph-like. Generally speaking, content is usually made out of blocks
	* like paragraphs, list items, images, headings, etc. All these elements are marked as blocks. A block
	* should not allow another block inside. Note: There is also the `$block` generic item which has `isBlock` set to `true`.
	* Most block type items will inherit from `$block` (through `inheritAllFrom`).
	*
	* Read more about the block elements in the
	* {@glink framework/deep-dive/schema#block-elements Block elements section} of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide.
	*/
	isBlock?: boolean;
	/**
	* Whether an item is "text-like" and should be treated as an inline node. Examples of inline elements:
	* `$text`, `softBreak` (`<br>`), etc.
	*
	* Read more about the inline elements in the
	* {@glink framework/deep-dive/schema#inline-elements Inline elements section} of the Schema deep-dive guide.
	*/
	isInline?: boolean;
	/**
	* It can be understood as whether this element should not be split by <kbd>Enter</kbd>.
	* Examples of limit elements: `$root`, table cell, image caption, etc. In other words, all actions that happen inside
	* a limit element are limited to its content.
	*
	* Read more about the limit elements in the
	* {@glink framework/deep-dive/schema#limit-elements Limit elements section} of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide.
	*/
	isLimit?: boolean;
	/**
	* Whether an item is "self-contained" and should be treated as a whole. Examples of object elements:
	* `imageBlock`, `table`, `video`, etc.
	*
	* **Note:** An object is also a limit, so
	* {@link module:engine/model/schema~ModelSchema#isLimit `isLimit()`} returns `true` for object elements automatically.
	*
	* Read more about the object elements in the
	* {@glink framework/deep-dive/schema#object-elements Object elements section} of the Schema deep-dive guide.
	*/
	isObject?: boolean;
	/**
	* `true` when an element should be selectable as a whole by the user.
	* Examples of selectable elements: `imageBlock`, `table`, `tableCell`, etc.
	*
	* **Note:** An object is also a selectable element, so
	* {@link module:engine/model/schema~ModelSchema#isSelectable `isSelectable()`} returns `true` for object elements automatically.
	*
	* Read more about selectable elements in the
	* {@glink framework/deep-dive/schema#selectable-elements Selectable elements section} of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide.
	*/
	isSelectable?: boolean;
	/**
	* An item is a content when it always finds its way to the editor data output regardless of the number and type of its descendants.
	* Examples of content elements: `$text`, `imageBlock`, `table`, etc. (but not `paragraph`, `heading1` or `tableCell`).
	*
	* **Note:** An object is also a content element, so
	* {@link module:engine/model/schema~ModelSchema#isContent `isContent()`} returns `true` for object elements automatically.
	*
	* Read more about content elements in the
	* {@glink framework/deep-dive/schema#content-elements Content elements section} of
	* the {@glink framework/deep-dive/schema Schema deep-dive} guide.
	*/
	isContent?: boolean;
}
/**
* A simplified version of {@link module:engine/model/schema~ModelSchemaItemDefinition} after
* compilation by the {@link module:engine/model/schema~ModelSchema schema}.
* Rules fed to the schema by {@link module:engine/model/schema~ModelSchema#register}
* and {@link module:engine/model/schema~ModelSchema#extend} methods are defined in the
* {@link module:engine/model/schema~ModelSchemaItemDefinition} format.
* Later on, they are compiled to `ModelSchemaCompiledItemDefinition` so when you use e.g.
* the {@link module:engine/model/schema~ModelSchema#getDefinition} method you get the compiled version.
*
* The compiled version contains only the following properties:
*
* * The `name` property,
* * The `is*` properties,
* * The `allowIn` array,
* * The `allowChildren` array,
* * The `allowAttributes` array.
*/
export interface ModelSchemaCompiledItemDefinition {
	name: string;
	isBlock: boolean;
	isContent: boolean;
	isInline: boolean;
	isLimit: boolean;
	isObject: boolean;
	isSelectable: boolean;
	allowIn: Array<string>;
	allowChildren: Array<string>;
	allowAttributes: Array<string>;
}
/**
* A schema context &ndash; a list of ancestors of a given position in the document.
*
* Considering such position:
*
* ```xml
* <$root>
* 	<blockQuote>
* 		<paragraph>
* 			^
* 		</paragraph>
* 	</blockQuote>
* </$root>
* ```
*
* The context of this position is its {@link module:engine/model/position~ModelPosition#getAncestors lists of ancestors}:
*
*		[ rootElement, blockQuoteElement, paragraphElement ]
*
* Contexts are used in the {@link module:engine/model/schema~ModelSchema#event:checkChild `Schema#checkChild`} and
* {@link module:engine/model/schema~ModelSchema#event:checkAttribute `Schema#checkAttribute`} events as a definition
* of a place in the document where the check occurs. The context instances are created based on the first arguments
* of the {@link module:engine/model/schema~ModelSchema#checkChild `Schema#checkChild()`} and
* {@link module:engine/model/schema~ModelSchema#checkAttribute `Schema#checkAttribute()`} methods so when
* using these methods you need to use {@link module:engine/model/schema~ModelSchemaContextDefinition}s.
*/
export declare class ModelSchemaContext implements Iterable<ModelSchemaContextItem> {
	private _items;
	/**
	* Creates an instance of the context.
	*/
	constructor(context: ModelSchemaContextDefinition);
	/**
	* The number of items.
	*/
	get length(): number;
	/**
	* The last item (the lowest node).
	*/
	get last(): ModelSchemaContextItem;
	/**
	* Iterable interface.
	*
	* Iterates over all context items.
	*/
	[Symbol.iterator](): IterableIterator<ModelSchemaContextItem>;
	/**
	* Returns a new schema context instance with an additional item.
	*
	* Item can be added as:
	*
	* ```ts
	* const context = new ModelSchemaContext( [ '$root' ] );
	*
	* // An element.
	* const fooElement = writer.createElement( 'fooElement' );
	* const newContext = context.push( fooElement ); // [ '$root', 'fooElement' ]
	*
	* // A text node.
	* const text = writer.createText( 'foobar' );
	* const newContext = context.push( text ); // [ '$root', '$text' ]
	*
	* // A string (element name).
	* const newContext = context.push( 'barElement' ); // [ '$root', 'barElement' ]
	* ```
	*
	* **Note** {@link module:engine/model/node~ModelNode} that is already in the model tree will be added as the only item
	* (without ancestors).
	*
	* @param item An item that will be added to the current context.
	* @returns A new schema context instance with an additional item.
	*/
	push(item: string | ModelNode): ModelSchemaContext;
	/**
	* Returns a new schema context that is based on this context but has the last item removed.
	*
	* ```ts
	* const ctxParagraph = new ModelSchemaContext( [ '$root', 'blockQuote', 'paragraph' ] );
	* const ctxBlockQuote = ctxParagraph.trimLast(); // Items in `ctxBlockQuote` are: `$root` an `blockQuote`.
	* const ctxRoot = ctxBlockQuote.trimLast(); // Items in `ctxRoot` are: `$root`.
	* ```
	*
	* @returns A new reduced schema context instance.
	*/
	trimLast(): ModelSchemaContext;
	/**
	* Gets an item on the given index.
	*/
	getItem(index: number): ModelSchemaContextItem;
	/**
	* Returns the names of items.
	*/
	getNames(): IterableIterator<string>;
	/**
	* Checks whether the context ends with the given nodes.
	*
	* ```ts
	* const ctx = new ModelSchemaContext( [ rootElement, paragraphElement, textNode ] );
	*
	* ctx.endsWith( '$text' ); // -> true
	* ctx.endsWith( 'paragraph $text' ); // -> true
	* ctx.endsWith( '$root' ); // -> false
	* ctx.endsWith( 'paragraph' ); // -> false
	* ```
	*/
	endsWith(query: string): boolean;
	/**
	* Checks whether the context starts with the given nodes.
	*
	* ```ts
	* const ctx = new ModelSchemaContext( [ rootElement, paragraphElement, textNode ] );
	*
	* ctx.endsWith( '$root' ); // -> true
	* ctx.endsWith( '$root paragraph' ); // -> true
	* ctx.endsWith( '$text' ); // -> false
	* ctx.endsWith( 'paragraph' ); // -> false
	* ```
	*/
	startsWith(query: string): boolean;
}
/**
* The definition of a {@link module:engine/model/schema~ModelSchemaContext schema context}.
*
* Contexts can be created in multiple ways:
*
* * By defining a **node** – in this cases this node and all its ancestors will be used.
* * By defining a **position** in the document – in this case all its ancestors will be used.
* * By defining an **array of nodes** – in this case this array defines the entire context.
* * By defining a **name of node** - in this case node will be "mocked". It is not recommended because context
* will be unrealistic (e.g. attributes of these nodes are not specified). However, at times this may be the only
* way to define the context (e.g. when checking some hypothetical situation).
* * By defining an **array of node names** (potentially, mixed with real nodes) – The same as **name of node**
* but it is possible to create a path.
* * By defining a {@link module:engine/model/schema~ModelSchemaContext} instance - in this case the same instance as provided
* will be returned.
*
* Examples of context definitions passed to the {@link module:engine/model/schema~ModelSchema#checkChild `Schema#checkChild()`}
* method:
*
* ```ts
* // Assuming that we have a $root > blockQuote > paragraph structure, the following code
* // will check node 'foo' in the following context:
* // [ rootElement, blockQuoteElement, paragraphElement ]
* const contextDefinition = paragraphElement;
* const childToCheck = 'foo';
* schema.checkChild( contextDefinition, childToCheck );
*
* // Also check in [ rootElement, blockQuoteElement, paragraphElement ].
* schema.checkChild( model.createPositionAt( paragraphElement, 0 ), 'foo' );
*
* // Check in [ rootElement, paragraphElement ].
* schema.checkChild( [ rootElement, paragraphElement ], 'foo' );
*
* // Check only fakeParagraphElement.
* schema.checkChild( 'paragraph', 'foo' );
*
* // Check in [ fakeRootElement, fakeBarElement, paragraphElement ].
* schema.checkChild( [ '$root', 'bar', paragraphElement ], 'foo' );
* ```
*
* All these `checkChild()` calls will fire {@link module:engine/model/schema~ModelSchema#event:checkChild `Schema#checkChild`}
* events in which `args[ 0 ]` is an instance of the context. Therefore, you can write a listener like this:
*
* ```ts
* schema.on( 'checkChild', ( evt, args ) => {
* 	const ctx = args[ 0 ];
*
* 	console.log( Array.from( ctx.getNames() ) );
* } );
* ```
*
* Which will log the following:
*
* ```ts
* [ '$root', 'blockQuote', 'paragraph' ]
* [ '$root', 'paragraph' ]
* [ '$root', 'bar', 'paragraph' ]
* ```
*
* Note: When using the {@link module:engine/model/schema~ModelSchema#checkAttribute `Schema#checkAttribute()`} method
* you may want to check whether a text node may have an attribute. A {@link module:engine/model/text~ModelText} is a
* correct way to define a context so you can do this:
*
* ```ts
* schema.checkAttribute( textNode, 'bold' );
* ```
*
* But sometimes you want to check whether a text at a given position might've had some attribute,
* in which case you can create a context by mixing in an array of elements with a `'$text'` string:
*
* ```ts
* // Check in [ rootElement, paragraphElement, textNode ].
* schema.checkChild( [ ...positionInParagraph.getAncestors(), '$text' ], 'bold' );
* ```
*/
export type ModelSchemaContextDefinition = ModelItem | ModelPosition | ModelSchemaContext | string | Array<string | ModelItem>;
/**
* An item of the {@link module:engine/model/schema~ModelSchemaContext schema context}.
*
* It contains 3 properties:
*
* * `name` – the name of this item,
* * `* getAttributeKeys()` – a generator of keys of item attributes,
* * `getAttribute( keyName )` – a method to get attribute values.
*
* The context item interface is a highly simplified version of {@link module:engine/model/node~ModelNode} and its role
* is to expose only the information which schema checks are able to provide (which is the name of the node and
* node's attributes).
*
* ```ts
* schema.on( 'checkChild', ( evt, args ) => {
* 	const ctx = args[ 0 ];
* 	const firstItem = ctx.getItem( 0 );
*
* 	console.log( firstItem.name ); // -> '$root'
* 	console.log( firstItem.getAttribute( 'foo' ) ); // -> 'bar'
* 	console.log( Array.from( firstItem.getAttributeKeys() ) ); // -> [ 'foo', 'faa' ]
* } );
* ```
*/
export interface ModelSchemaContextItem {
	name: string;
	getAttributeKeys(): Generator<string>;
	getAttribute(keyName: string): unknown;
}
/**
* A structure containing additional metadata describing the attribute.
*
* See {@link module:engine/model/schema~ModelSchema#setAttributeProperties `Schema#setAttributeProperties()`} for usage examples.
*/
export interface ModelAttributeProperties {
	/**
	* Indicates that the attribute should be considered as a visual formatting, like `bold`, `italic` or
	* `fontSize` rather than semantic attribute (such as `src`, `listType`, etc.). For example, it is used by the "Remove format" feature.
	*/
	isFormatting?: boolean;
	/**
	* Indicates that given text attribute should be copied to the next block when enter is pressed.
	*/
	copyOnEnter?: boolean;
	/**
	* Indicates that given attribute should be preserved while replacing the element.
	*/
	copyOnReplace?: boolean;
	/**
	* Indicates that given text attribute should be copied from an inline object to the next inserted inline content.
	*
	* @default true
	*/
	copyFromObject?: boolean;
	/**
	* Defines the mapping of all possible block alignments for a specific model element.
	* It is used by features that need to determine whether an element can be aligned,
	* and apply the alignment if possible.
	*/
	blockAlignment?: ModelBlockAlignmentAttributesMapping | ((element: ModelElement) => ModelBlockAlignmentAttributesMapping);
	[name: string]: unknown;
}
/**
* Defines the mapping of block alignment options for a model element attribute.
*
* Each key represents a logical alignment name (e.g. `'left'`, `'center'`, `'right'`, `'justify'`),
* and the corresponding value describes how that alignment is represented in the model — including
* the actual attribute value and whether it should be treated as the default alignment for the element.
*
* Used by features that need to determine whether a model element supports block alignment
* and how to apply it. Can be provided as a static object or as a function receiving the element
* and returning the mapping dynamically, via {@link ~ModelAttributeProperties#blockAlignment}.
*/
export type ModelBlockAlignmentAttributesMapping = Record<string, {
	isDefault?: boolean;
	value: string;
}>;
export type ModelSchemaAttributeCheckCallback = (context: ModelSchemaContext, attributeName: string) => boolean | undefined;
export type ModelSchemaChildCheckCallback = (context: ModelSchemaContext, definition: ModelSchemaCompiledItemDefinition) => boolean | undefined;
export {};