NlpTools\Utils\TransformationInterface

TransformationInterface represents any type of transformation to be applied upon documents.

The transformation is defined upon
single values and how each document applies a transformation
differs. For instance TokensDocument should apply the transformation
on each token but EuclideanDocument could apply it on each key (dimension).

There can be combinations of transformations and documents that make
no sense. For instance if we have a scaling transformation that expects
numeric values and returns them multiplied by a constant c, it
would make little sense to pass this transformation to
TokensDocument that expects transformations to be applied on
specific tokens.