Metrics of syntactic complexity

Explanatory introduction TBA: see API listings for basic docstrings.

Tokens

distance: number of lexical tokens from t1 to its syntactic connection in a sentence
displacement: number of lexical tokens between t1 to its syntactic connection in a sentence

Verbal expressions

span: distance from first to last token in group
cohesion: proportion of tokens with span belonging to group
displacement: number of groups between start and end of span

Sentences

maxdepth: maximum syntactic level of a sentence
maxtokendistance
avgtokendistance
maxgroupdistance
avggroupdistance