Add morpheme_list

[mh-northlander]

#55
Replace Vec<Morpheme> by MorphemeList.

[mh-northlander]

Maybe it's better to let Morpheme have Deref<trait morpheme-list> instead of the reference to concrete MorphemeList type

[eiennohito]

Also, I didn't understand the comment about Deref.

[mh-northlander]

Also, I didn't understand the comment about Deref.

I'm wondering if we can reuse code in python bind part like:

// rust side
struct Morpheme<T> {
    list: T,
    index: usize,
}
impl <T> Morpheme where T: Deref, <T as Deref>::Target: MorphemeListTrait {
    /// 
}

// python side
impl MorphemeListTrait for PyMorphemeList { /// }

struct PyMorpheme {
    inner: Morpheme<Arc<PyMorphemeList>>
}

[eiennohito]

I believe that Pyo3 does not allow to expose methods from trait implementations to Python, so that part can't go away.

Also, lazy loading WordInfo will require having mutable references to everything, which is not a good thing.

[mh-northlander]

I believe that Pyo3 does not allow to expose methods from trait implementations to Python, so that part can't go away.

Yes, anyway we need to write code to expose functions.
I leave this idea for later.

Also, lazy loading WordInfo will require having mutable references to everything, which is not a good thing.

I faced problems around this and remove WordInfo field.

[mh-northlander]

I changed the type of MorphemeList.input_text from &str to String.
I guess it's better to have &str from the view point of allocation, but failed to pass the reference to the original input text through analysis.

[eiennohito]

It's OK to have the String there internally. In the memory reuse case we will swap it with the Utf8InputText buffer.

[eiennohito]

you probably meant pub(super)