registerFunctions: Register R functions as external Zorba functions
In omegahat/RXQuery: Bi-directional interface to an XQuery engine

Description Usage Arguments Author(s) References See Also

We can use R functions as part of Zorba queries by registering these R functions as external functions with the Zorba engine. We do this (in Zorba 1.0.0) by creating an external module and then associating it with a static context which is used in the evaluation of the Zorba query. The external module

We could have an external module that looks up the R object by name along the R search path (or within a particular R environment) and that does not require explicitly registering the functions by name. This is similar to RObjectTables.

registerFunctions(module, factory = itemFactory(), ...,
                  .funcs = list(...),
                   .deterministic = rep(TRUE, length(.funcs)),
                    fix = length(names(.funcs)) == 0 || any(names(.funcs) == ""))

createModule(urn = "urn:R", ctxt = makeContext(zorba()), e = new.env(), 
              obj = new("RExternalModule"), register = !missing(ctxt)) 
getEnvironment(from, ...)

`module`	the ExternalModule object in which these functions will be registered.
`factory`	the ItemFactory to use for the functions
`...`	the collection of functions specified individually in the call
`.funcs`	the collection of functions specified as a single list
`.deterministic`	a logical vector with as many elements as there are functions being registered. A value of `FALSE` indicates that the function should be called with two additional parameters - the static and dynamic Zorba context associated with the Zorba query being evaluated.
`fix`	a logical value indicating whether the functions need to be processed to determine their names.
`from`	the ExternalModule whose environment is being requested.
`urn`	the namespace for these functions
`ctxt`	the zorba::StaticContext in which to register these functions
`e`	the environment to use for the ExternalModule to house the R functions.
`obj`	the object that will be filled in when creating the ExternalModule.
`register`	whether to register the module with the specified context.