`runGetChunk` use case? about cereal

[winterland1989]

The same quetion goes to Buffer as well, since all run... functions provide Nothing as Buffer, why do we keep it in the codebase at all?

[elliottt]

There's a good chance that it exists because the API has evolved over time.

The Buffer type is used to keep track of chunks read across choice points. Without it, backtracking across a chunk read will request a new chunk.

[elliottt]

Now I remember, the Incomplete tag is for when the action is being run from runGetPartial, and explicitly run as something that may expect another chunk. The Maybe Int field of the constructor indicates whether or not you know the length of the whole input. So, if you were streaming from a network connection, each chunk you passed in would be given Incomplete Nothing as the input, but if you were streaming from a file, you could pass Incomplete (Just size).

runGetChunk is just a convenient wrapper for exposing the incremental interface.

[winterland1989]

I see, i don't even know cereal support backtrace before ; ), Thanks!