codemirror-lang-mermaid/src/parsers/requirement/tokens.ts

Mermaid language support for CodeMirror

import { ExternalTokenizer } from '@lezer/lr';
import { RelationshipStart } from './requirement.grammar.terms';

const notAllowedCodePoints = [-1, 45, 60, 62, 10, 13, 123, 61];

export const relationshipStart = new ExternalTokenizer((input) => {
  if (notAllowedCodePoints.includes(input.next) || input.next === 32) return;

  let peek;
  let tokens = '';
  let count = 0;

  do {
    peek = input.peek(count);
    if (peek === -1) return;
    tokens += String.fromCodePoint(peek);
    count++;
  } while (!notAllowedCodePoints.includes(peek));

  if (peek === 45 || peek === 60) {
    tokens = tokens.slice(0, -1).trim();
    input.acceptToken(RelationshipStart, tokens.length);
  }
});