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39 lines
2.2 KiB
39 lines
2.2 KiB
import type { CollectionItem, Document } from './cst.js'; |
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export declare type VisitPath = readonly ['key' | 'value', number][]; |
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export declare type Visitor = (item: CollectionItem, path: VisitPath) => number | symbol | Visitor | void; |
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/** |
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* Apply a visitor to a CST document or item. |
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* |
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* Walks through the tree (depth-first) starting from the root, calling a |
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* `visitor` function with two arguments when entering each item: |
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* - `item`: The current item, which included the following members: |
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* - `start: SourceToken[]` – Source tokens before the key or value, |
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* possibly including its anchor or tag. |
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* - `key?: Token | null` – Set for pair values. May then be `null`, if |
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* the key before the `:` separator is empty. |
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* - `sep?: SourceToken[]` – Source tokens between the key and the value, |
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* which should include the `:` map value indicator if `value` is set. |
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* - `value?: Token` – The value of a sequence item, or of a map pair. |
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* - `path`: The steps from the root to the current node, as an array of |
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* `['key' | 'value', number]` tuples. |
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* |
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* The return value of the visitor may be used to control the traversal: |
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* - `undefined` (default): Do nothing and continue |
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* - `visit.SKIP`: Do not visit the children of this token, continue with |
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* next sibling |
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* - `visit.BREAK`: Terminate traversal completely |
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* - `visit.REMOVE`: Remove the current item, then continue with the next one |
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* - `number`: Set the index of the next step. This is useful especially if |
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* the index of the current token has changed. |
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* - `function`: Define the next visitor for this item. After the original |
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* visitor is called on item entry, next visitors are called after handling |
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* a non-empty `key` and when exiting the item. |
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*/ |
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export declare function visit(cst: Document | CollectionItem, visitor: Visitor): void; |
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export declare namespace visit { |
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var BREAK: symbol; |
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var SKIP: symbol; |
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var REMOVE: symbol; |
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var itemAtPath: (cst: Document | CollectionItem, path: VisitPath) => CollectionItem | undefined; |
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var parentCollection: (cst: Document | CollectionItem, path: VisitPath) => import("./cst.js").BlockMap | import("./cst.js").BlockSequence | import("./cst.js").FlowCollection; |
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}
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