async-graphql/src/validation/suggestion.rs

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Rust
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use itertools::Itertools;
use std::collections::HashMap;
fn levenshtein_distance(s1: &str, s2: &str) -> usize {
let mut column = (0..=s1.len()).collect_vec();
for (x, rx) in s2.bytes().enumerate() {
column[0] = x + 1;
let mut lastdiag = x;
for (y, ry) in s1.bytes().enumerate() {
let olddiag = column[y + 1];
if rx != ry {
lastdiag += 1;
}
column[y + 1] = (column[y + 1] + 1).min((column[y] + 1).min(lastdiag));
lastdiag = olddiag;
}
}
column[s1.len()]
}
pub fn make_suggestion<'a, I>(prefix: &str, options: I, input: &str) -> Option<String>
where
I: Iterator<Item = &'a str>,
{
let mut selected = Vec::new();
let mut distances = HashMap::new();
for opt in options {
let distance = levenshtein_distance(input, opt);
let threshold = (input.len() / 2).max((opt.len() / 2).max(1));
if distance < threshold {
selected.push(opt);
distances.insert(opt, distance);
}
}
if selected.is_empty() {
return None;
}
selected.sort_by(|a, b| distances[a].cmp(&distances[b]));
Some(format!(
"{} {}?",
prefix,
selected
.into_iter()
.map(|s| format!("\"{}\"", s))
.join(", ")
))
}