Passing type arguments

[Simon Hafner]

The problem: How to pass the input types to an annotator. Possible solutions:

a) Actually don't have different input types. Force everything to be
Sentence, Token, etc.
Drawback: No more object hierarchies.

b) Make the compiler find out the types. That's what I did originally.
Makes the best API.

val sentenceSegmenter = epic.preprocess.MLSentenceSegmenter.bundled().get
val tokenizer = epic.preprocess.TreebankTokenizer
val slabs = documents.map(Slab(_))
.map(sentenceSegmenter(_))
.map(tokenizer(_))

Drawback: ~ 20-30s compiletime per pipeline. Unacceptable.

c) Pass the types as arguments to the constructor.

val sentenceSegmenter = epic.preprocess.MLSentenceSegmenter.bundled().get
val tokenizer = epic.preprocess.TreebankTokenizer.slab[Sentence]
val parser =
epic.models.ParserSelector.loadParser("en").get.slab[Sentence,
ContentToken]
val slabs = documents.map(Slab(_))
.map(sentenceSegmenter(_))
.map(tokenizer(_))
.map(parser(_))

Drawback: Doesn't work for the parser, because the apply for slabs is
via implicit class. Would need to do it explicitly, shouldn't be too
big of a problem.

d) Via apply method.

val sentenceSegmenter = epic.preprocess.MLSentenceSegmenter.bundled().get
val tokenizer = epic.preprocess.TreebankTokenizer
val parser = epic.models.ParserSelector.loadParser("en").get
val slabs = documents.map(Slab(_))
.map(sentenceSegmenter(_))
.map(tokenizer[Sentence](_))
.map(parser[Sentence, ContentToken](_))

Drawback: Doesn't really work, because the type information is passed
around at class level. Would require some major rewrite of slab code.

e) Your solution.