detritus: Initial commit

src/lib.rs

@@ -0,0 +1,180 @@
+//! Implements a trie on T9 numpads
+//!
+//! # T9:
+//! 1:     2:abc  3:def
+//! 4:ghi  5:jkl  6:mno
+//! 7:pqrs 8:tuv  9:wxyz
+
+use std::{
+    collections::VecDeque,
+    ops::{Index, IndexMut},
+};
+
+#[derive(Debug, Default)]
+pub struct Trie9 {
+    pub link: Option<Box<[Trie9; 8]>>,
+    pub leaf: Vec<String>,
+}
+
+impl Trie9 {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn insert(&mut self, string: &str) -> bool {
+        let Some(trie) = self.at_mut(string.chars()) else {
+            return false;
+        };
+
+        trie.leaf.push(string.into());
+        true
+    }
+
+    pub fn get(&self, index: T9) -> Option<&Trie9> {
+        self.link.as_ref()?.get(index as usize)
+    }
+
+    pub fn get_mut(&mut self, index: T9) -> Option<&mut Trie9> {
+        self.link.as_mut()?.get_mut(index as usize)
+    }
+
+    pub fn get_or_insert(&mut self, index: T9) -> &mut Trie9 {
+        self.link
+            .get_or_insert_default()
+            .get_mut(index as usize)
+            .expect("link exists at all T9 indices")
+    }
+
+    pub fn at<Iter, T>(&self, code: Iter) -> Option<&Self>
+    where
+        Iter: IntoIterator<Item = T>,
+        T: TryInto<T9>,
+    {
+        let mut code = code.into_iter();
+        match code.next() {
+            None => Some(self),
+            Some(link) => self.get(link.try_into().ok()?)?.at(code),
+        }
+    }
+
+    pub fn at_mut<Iter, T>(&mut self, code: Iter) -> Option<&mut Self>
+    where
+        Iter: IntoIterator<Item = T>,
+        T: TryInto<T9>,
+    {
+        let mut code = code.into_iter();
+        match code.next() {
+            None => Some(self),
+            Some(link) => self.get_or_insert(link.try_into().ok()?).at_mut(code),
+        }
+    }
+
+    pub fn iter<'t>(&'t self) -> Trie9Iter<'t> {
+        Trie9Iter::new(self)
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct Trie9Iter<'t9> {
+    queue: VecDeque<&'t9 Trie9>,
+    items: std::slice::Iter<'t9, String>,
+}
+
+impl<'t> Trie9Iter<'t> {
+    pub fn new(trie: &'t Trie9) -> Self {
+        Self { queue: VecDeque::from([trie]), items: Default::default() }
+    }
+}
+
+impl<'t> Iterator for Trie9Iter<'t> {
+    type Item = &'t str;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let Self { queue, items } = self;
+
+        if let Some(item) = items.next() {
+            return Some(item.as_str());
+        }
+
+        let Trie9 { link, leaf } = queue.pop_front()?;
+        *items = leaf.iter();
+        queue.extend(link.iter().flat_map(|v| v.iter()));
+
+        self.next()
+    }
+}
+
+impl<'t> IntoIterator for &'t Trie9 {
+    type IntoIter = Trie9Iter<'t>;
+    type Item = &'t str;
+
+    fn into_iter(self) -> Self::IntoIter {
+        Self::IntoIter::new(self)
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum T9 {
+    T2,
+    T3,
+    T4,
+    T5,
+    T6,
+    T7,
+    T8,
+    T9,
+}
+
+impl From<T9> for u8 {
+    fn from(value: T9) -> Self {
+        value as u8 + 2
+    }
+}
+
+impl From<T9> for char {
+    fn from(value: T9) -> Self {
+        match value {
+            T9::T2 => '2',
+            T9::T3 => '3',
+            T9::T4 => '4',
+            T9::T5 => '5',
+            T9::T6 => '6',
+            T9::T7 => '7',
+            T9::T8 => '8',
+            T9::T9 => '9',
+        }
+    }
+}
+
+impl TryFrom<char> for T9 {
+    type Error = char;
+    fn try_from(value: char) -> Result<Self, Self::Error> {
+        Ok(match value {
+            '2' | 'A'..='C' | 'a'..='c' | 'À'..='Æ' | 'à'..='æ' | 'Ç' | 'ç' => Self::T2,
+            '3' | 'D'..='F' | 'd'..='f' | 'È'..='Ë' | 'è'..='ë' => Self::T3,
+            '4' | 'G'..='I' | 'g'..='i' | 'Ì'..='Ï' | 'ì'..='ï' => Self::T4,
+            '5' | 'J'..='L' | 'j'..='l' | '1' => Self::T5,
+            '6' | 'M'..='O' | 'm'..='o' | 'Ò'..='Ø' | 'ò'..='ø' | '0' => Self::T6,
+            '7' | 'P'..='S' | 'p'..='s' => Self::T7,
+            '8' | 'T'..='V' | 't'..='v' | 'Ù'..='Ü' | 'ù'..='ü' => Self::T8,
+            '9' | 'W'..='Z' | 'w'..='z' => Self::T9,
+            _ => Err(value)?,
+        })
+    }
+}
+
+impl Index<T9> for Trie9 {
+    type Output = Trie9;
+    fn index(&self, index: T9) -> &Self::Output {
+        let Some(link) = self.get(index) else {
+            panic!("No Trie9 at index {index:?}");
+        };
+        link
+    }
+}
+
+impl IndexMut<T9> for Trie9 {
+    fn index_mut(&mut self, index: T9) -> &mut Self::Output {
+        self.get_or_insert(index)
+    }
+}

src/main.rs

@@ -0,0 +1,70 @@
+//! Solves a fun little puzzle invented by a coworker
+
+use detritus::{T9, Trie9};
+use repline::prebaked::*;
+use std::{
+    error::Error,
+    fs::File,
+    io::{BufRead, BufReader, IsTerminal, Write},
+};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let mut trie = Trie9::new();
+
+    // "Parse" CLI arg
+    let args: Vec<_> = std::env::args().skip(1).collect();
+    let path = match args.as_slice() {
+        [] => "/usr/share/dict/words",
+        [path] => path,
+        _ => Err("Usage: detritus [dict]")?,
+    };
+
+    // Read in the database and construct the Trie9
+    for line in BufReader::new(File::open(path)?).lines() {
+        trie.insert(&line?);
+    }
+
+    if std::io::stdin().is_terminal() {
+        yestty(trie)
+    } else {
+        notty(trie)
+    }
+}
+
+fn yestty(trie: Trie9) -> Result<(), Box<dyn Error>> {
+    repline::read_and("\x1b[36m", " t>", " ?>", |line| {
+        let key: Vec<_> = match line.trim().chars().map(T9::try_from).collect() {
+            Ok(t9) => t9,
+            Err(e) => {
+                println!("Unexpected character: {e}");
+                return Ok(Response::Deny);
+            }
+        };
+
+        key.iter().for_each(|&c| print!("{}", char::from(c)));
+        println!();
+
+        let Some(trie) = trie.at(key.iter().copied()) else {
+            return Ok(Response::Accept);
+        };
+        for item in trie {
+            println!("{item}")
+        }
+
+        Ok(Response::Accept)
+    })?;
+    Ok(())
+}
+
+fn notty(trie: Trie9) -> Result<(), Box<dyn Error>> {
+    let stdin = std::io::stdin().lock();
+    let key = std::io::read_to_string(stdin)?;
+    if let Some(trie) = trie.at(key.trim().chars()) {
+        for word in trie.iter() {
+            if writeln!(std::io::stdout(), "{word}").is_err() {
+                break;
+            }
+        }
+    }
+    Ok(())
+}