/
signature-help-provider.ts
79 lines (70 loc) · 3.33 KB
/
signature-help-provider.ts
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/******************************************************************************
* Copyright 2022 TypeFox GmbH
* This program and the accompanying materials are made available under the
* terms of the MIT License, which is available in the project root.
******************************************************************************/
import type { SignatureHelp, SignatureHelpOptions, SignatureHelpParams } from 'vscode-languageserver';
import { CancellationToken } from '../utils/cancellation.js';
import type { AstNode } from '../syntax-tree.js';
import { findLeafNodeAtOffset } from '../utils/cst-utils.js';
import type { MaybePromise } from '../utils/promise-utils.js';
import type { LangiumDocument } from '../workspace/documents.js';
/**
* Language-specific service for handling signature help requests.
*/
export interface SignatureHelpProvider {
/**
* Handles a signature help request
*/
provideSignatureHelp(document: LangiumDocument, params: SignatureHelpParams, cancelToken?: CancellationToken): MaybePromise<SignatureHelp | undefined>;
/**
* Options that determine the server capabilities for a signature help request. It contains the list of triggering characters.
*/
get signatureHelpOptions(): SignatureHelpOptions;
}
export abstract class AbstractSignatureHelpProvider implements SignatureHelpProvider {
provideSignatureHelp(document: LangiumDocument, params: SignatureHelpParams, cancelToken = CancellationToken.None): MaybePromise<SignatureHelp | undefined> {
const rootNode = document.parseResult.value;
const cst = rootNode.$cstNode;
if (cst) {
const sourceCstNode = findLeafNodeAtOffset(cst, document.textDocument.offsetAt(params.position));
if (sourceCstNode) {
return this.getSignatureFromElement(sourceCstNode.astNode, cancelToken);
}
}
return undefined;
}
/**
* Override this method to return the desired SignatureHelp
*/
protected abstract getSignatureFromElement(element: AstNode, cancelToken: CancellationToken): MaybePromise<SignatureHelp | undefined>;
/**
* Override this getter to return the list of triggering characters for your language. To deactivate the signature help, return an empty object.
*/
get signatureHelpOptions(): SignatureHelpOptions {
return {
triggerCharacters: ['('],
retriggerCharacters: [',']
};
}
}
/**
* Merges the SignatureHelpOptions of all languages
*/
export function mergeSignatureHelpOptions(options: Array<SignatureHelpOptions | undefined>): SignatureHelpOptions | undefined {
const triggerCharacters: string[] = [];
const retriggerCharacters: string[] = [];
options.forEach(option => {
if (option?.triggerCharacters) {
triggerCharacters.push(...option.triggerCharacters);
}
if (option?.retriggerCharacters) {
retriggerCharacters.push(...option.retriggerCharacters);
}
});
const mergedOptions: SignatureHelpOptions = {
triggerCharacters: triggerCharacters.length > 0 ? Array.from(new Set(triggerCharacters)).sort() : undefined,
retriggerCharacters: retriggerCharacters.length > 0 ? Array.from(new Set(retriggerCharacters)).sort() : undefined
};
return mergedOptions.triggerCharacters ? mergedOptions : undefined;
}