Function key

packages/compiler/src/output/output_ast.ts:226–228

(index: Expression, type?: Type | null, sourceSpan?: ParseSourceSpan | null)

  }

  key(index: Expression, type?: Type | null, sourceSpan?: ParseSourceSpan | null): ReadKeyExpr {
    return new ReadKeyExpr(this, index, type, sourceSpan);
  }

  callFn(
    params: Expression[],