ngram.rs

#[derive(Debug, PartialEq)]
struct Ngram {
    tokens: Vec<String>,
    year: i32,
    count: i64,
    docs: i32
}

impl FromStr for Ngram {
    type Err = ParseIntError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let mut parts: Vec<String> = s.split_whitespace().map(|s| s.to_string()).collect();
        let len = parts.len();
        let year = parts[len - 3].parse::<i32>()?;
        let count = parts[len - 2].parse::<i64>()?;
        let docs = parts[len - 1].parse::<i32>()?;
        parts.truncate(len - 3);
        Ok(Ngram { tokens: parts, year: year, count: count, docs: docs })
    }
}