Rather than give the full power of cascading's selectors, we have a simpler set of rules encoded below: 1) if the input is non-definite (ALL, GROUP, ARGS, etc.
Rather than give the full power of cascading's selectors, we have a simpler set of rules encoded below: 1) if the input is non-definite (ALL, GROUP, ARGS, etc...) ALL is the output. Perhaps only fromFields=ALL will make sense 2) If one of from or to is a strict super set of the other, SWAP is used. 3) If they are equal, REPLACE is used. 4) Otherwise, ALL is used.
We can't set the field Manifests because cascading doesn't (yet) expose field type information in the Fields API.
We can't set the field Manifests because cascading doesn't (yet) expose field type information in the Fields API.
Enrichment on FlowDef
Multi-entry fields.
Multi-entry fields. This are higher priority than Product conversions so that List will not conflict with Product.
Useful to convert f : Any* to Fields.
Useful to convert f : Any* to Fields. This handles mixed cases ("hey", 'you). Not sure we should be this flexible, but given that Cascading will throw an exception before scheduling the job, I guess this is okay.
Handles treating any TupleN as a Fields object.
Handles treating any TupleN as a Fields object. This is low priority because List is also a Product, but this method will not work for List (because List is Product2(head, tail) and so productIterator won't work as expected. Lists are handled by an implicit in FieldConversions, which have higher priority.
'* means Fields.
'* means Fields.ALL, otherwise we take the .name
This object has all the implicit functions and values that are used to make the scalding DSL, which includes the functions for automatically creating cascading.tuple.Fields objects from scala tuples of Strings, Symbols or Ints, as well as the cascading.pipe.Pipe enrichment to RichPipe which adds the scala.collections-like API to Pipe.
It's useful to import Dsl._ when you are writing scalding code outside of a Job.