Method evaluateIndex

src/vimscript/expression/evaluate.ts:402–434

(sequence: Value, index: Value)

  }

  private evaluateIndex(sequence: Value, index: Value): Value {
    switch (sequence.type) {
      case 'string':
      case 'number':
      case 'float': {
        const idx = toInt(index);
        return str(idx >= 0 ? (toString(sequence)[idx] ?? '') : '');
      }
      case 'list': {
        let idx = toInt(index);
        idx = idx < 0 ? sequence.items.length - idx : idx;
        if (idx < 0 || idx >= sequence.items.length) {
          throw VimError.ListIndexOutOfRange(idx);
        }
        return sequence.items[idx];
      }
      case 'dictionary': {
        const key = toString(index);
        const result = sequence.items.get(key);
        if (result === undefined) {
          throw VimError.KeyNotPresentInDictionary(key);
        }
        return result;
      }
      case 'funcref': {
        throw VimError.CannotIndexAFuncref();
      }
      case 'blob': {
        const bytes = new Uint8Array(sequence.data);
        return int(bytes[toInt(index)]);
      }
    }
  }

  private evaluateSlice(sequence: Value, start: Value, end: Value): Value {
    let _start = toInt(start);