Text-only sumtree

index.js

import { buildModule, defaultNodeSize } from '@bablr/btree/enhanceable';

const { isArray } = Array;
const { freeze } = Object;

const LiteralTag = Symbol.for('LiteralTag');

export { defaultNodeSize };

export const {
  treeFrom,
  treeFromValues,
  pop,
  push,
  addAt,
  isValidNode,
  assertValidNode,
  getValues,
  getSums,
  setValues,
  isLeafNode,
  traverse,
  getSize,
  findPath,
  getAt,
  replaceAt,
} = buildModule(
  defaultNodeSize,
  (acc, val) => {
    const { references } = acc;
    if (isArray(val)) {
      acc.lineBreaks += val[2].lineBreaks;
    } else {
      if (val.type === LiteralTag) {
        let text = val.value;
        let idx = 0;
        while ((idx = text.indexOf('\n', idx + 1)) >= 0) {
          acc.lineBreaks++;
        }
      } else {
        throw new Error('unimplemented');
      }
    }
    return acc;
  },
  () => ({
    lineBreaks: 0,
  }),
  (stats) => {
    freeze(stats);
  },
);