Bookmarking of tokens in a set of streaming tokens, each representing an instantiation instruction or instantiation context. A navigator receives a set of streaming tokens, and provides the tokens to the instantiation manager. However, if the navigator receives an instruction to bookmark a particular token, the navigator buffers the set of streaming instructions at least beginning at the bookmarked token (and possible even earlier if there were prior bookmarks). The navigator replays the set of streaming tokens beginning at a bookmark in response to an instruction from an instantiation manager. The instantiation manager receives the set of streaming tokens. If the instantiation manager is not presently capable of handling the instruction of a particular token, the instantiation manager instructs the navigator to bookmark the particular token. When the instantiation manager later receives a token that permits the instantiation manager to return to the bookmark, the instantiation manager returns to the bookmark to replay the instantiation instructions beginning at the bookmark.