  We propose a novel transition-based algorithm that straightforwardly parses
sentences from left to right by building $n$ attachments, with $n$ being the
length of the input sentence. Similarly to the recent stack-pointer parser by
Ma et al. (2018), we use the pointer network framework that, given a word, can
directly point to a position from the sentence. However, our left-to-right
approach is simpler than the original top-down stack-pointer parser (not
requiring a stack) and reduces transition sequence length in half, from 2$n$-1
actions to $n$. This results in a quadratic non-projective parser that runs
twice as fast as the original while achieving the best accuracy to date on the
English PTB dataset (96.04% UAS, 94.43% LAS) among fully-supervised
single-model dependency parsers, and improves over the former top-down
transition system in the majority of languages tested.
