This is the main entry for using the Dx API.

• get/3 evaluates the given predicate(s) using only the (pre)loaded data available, and returns the result(s)
• load/3 is like get, but loads any additional data as needed
• put/3 is like load, but puts the results into the :inferred field (or virtual schema field) of the subject(s) as a map, and returns the subject(s)

These functions return a tuple, either {:ok, result}, {:error, error}, or {:not_loaded, data_reqs} (only get).

The corresponding get!/3, load!/3 and put!/3 functions return result directly, or otherwise raise an exception.

Arguments:

• subjects can either be an individual subject (with the given predicates defined on it), or a list of subjects. Passing an individual subject will return the predicates for the subject, passing a list will return a list of them.
• predicates can either be a single predicate, or a list of predicates. Passing a single predicate will return the resulting value, passing a list will return a Map of the predicates and their resulting values.
• options (optional) See below.

Options:

• args (list or map) can be used to pass in data from the caller's context that can be used in rules (see Arguments below). A classic example is the current_user, e.g.

  put!(project, :can_edit?, args: [user: current_user])

• extra_rules (module or list of modules) can be used to add context-specific rules that are not defined directly on the subject. This can be used to structure rules into their own modules and use them only where needed.
• debug (boolean) makes Dx print additional information to the console as rules are evaluated. Should only be used while debugging.
• return_cache (boolean) makes non-bang functions return {:ok, result, cache} instead of {:ok, result} on success. This cache can be passed to other Dx functions (see cache option)
• cache (Dataloader struct) can be used to pass in an existing cache, so data already loaded doesn't need to be loaded again. Can be initialized using Dx.Loaders.Dataloader.init/1.
• loader allows choosing a loader module. Defaults to Dx.Loaders.Dataloader.
• loader_options are passed to loader.init/1 function. See Dx.Loaders.Dataloader for options supported by the default loader.