Split query_term module into multiple submodules

milli/src/search/new/logger/detailed.rs

@@ -8,9 +8,7 @@ use roaring::RoaringBitmap;
 
 use crate::search::new::interner::{Interned, MappedInterner};
 use crate::search::new::query_graph::QueryNodeData;
-use crate::search::new::query_term::{
+use crate::search::new::query_term::LocatedQueryTermSubset;
-    Lazy, LocatedQueryTermSubset, OneTypoTerm, QueryTerm, TwoTypoTerm, ZeroTypoTerm,
-};
 use crate::search::new::ranking_rule_graph::{
     DeadEndsCache, Edge, ProximityCondition, ProximityGraph, RankingRuleGraph,
     RankingRuleGraphTrait, TypoCondition, TypoGraph,
@@ -439,87 +437,26 @@ results.{cur_ranking_rule}{cur_activated_id} {{
                 positions: _,
                 term_ids: _,
             }) => {
-                let QueryTerm {
-                    original,
-                    is_multiple_words: _,
-                    is_prefix: _,
-                    max_nbr_typos,
-                    zero_typo,
-                    one_typo,
-                    two_typo,
-                } = ctx.term_interner.get(term_subset.original);
-
-                let original = ctx.word_interner.get(*original);
                 writeln!(
                     file,
-                    "{node_idx} : \"{original}\" {{
+                    "{node_idx} : \"{}\" {{
                 shape: class
-                max_nbr_typo: {max_nbr_typos}"
+                max_nbr_typo: {}",
+                    term_subset.description(ctx),
+                    term_subset.max_nbr_typos(ctx)
                 )
                 .unwrap();
 
-                let ZeroTypoTerm { phrase, zero_typo, prefix_of, synonyms, use_prefix_db } =
+                for w in term_subset.all_single_words_except_prefix_db(ctx).unwrap() {
-                    zero_typo;
-
-                for w in zero_typo.iter().copied() {
-                    if term_subset.zero_typo_subset.contains_word(w) {
                     let w = ctx.word_interner.get(w);
-                        writeln!(file, "\"{w}\" : 0").unwrap();
+                    writeln!(file, "{w}: word").unwrap();
                 }
+                for p in term_subset.all_phrases(ctx).unwrap() {
+                    writeln!(file, "{}: phrase", p.description(ctx)).unwrap();
                 }
-                for w in prefix_of.iter().copied() {
+                if let Some(w) = term_subset.use_prefix_db(ctx) {
-                    if term_subset.zero_typo_subset.contains_word(w) {
                     let w = ctx.word_interner.get(w);
-                        writeln!(file, "\"{w}\" : 0P").unwrap();
+                    writeln!(file, "{w}: prefix db").unwrap();
-                    }
-                }
-
-                if let Some(phrase) = phrase {
-                    if term_subset.zero_typo_subset.contains_phrase(*phrase) {
-                        let phrase = ctx.phrase_interner.get(*phrase);
-                        let phrase_str = phrase.description(&ctx.word_interner);
-                        writeln!(file, "\"{phrase_str}\" : phrase").unwrap();
-                    }
-                }
-
-                for synonym in synonyms.iter().copied() {
-                    if term_subset.zero_typo_subset.contains_phrase(synonym) {
-                        let phrase = ctx.phrase_interner.get(synonym);
-                        let phrase_str = phrase.description(&ctx.word_interner);
-                        writeln!(file, "\"{phrase_str}\" : synonym").unwrap();
-                    }
-                }
-                if let Some(use_prefix_db) = use_prefix_db {
-                    if term_subset.zero_typo_subset.contains_word(*use_prefix_db) {
-                        let p = ctx.word_interner.get(*use_prefix_db);
-                        writeln!(file, "use prefix DB : {p}").unwrap();
-                    }
-                }
-                if let Lazy::Init(one_typo) = one_typo {
-                    let OneTypoTerm { split_words, one_typo } = one_typo;
-
-                    for w in one_typo.iter().copied() {
-                        if term_subset.one_typo_subset.contains_word(w) {
-                            let w = ctx.word_interner.get(w);
-                            writeln!(file, "\"{w}\" : 1").unwrap();
-                        }
-                    }
-                    if let Some(split_words) = split_words {
-                        if term_subset.one_typo_subset.contains_phrase(*split_words) {
-                            let phrase = ctx.phrase_interner.get(*split_words);
-                            let phrase_str = phrase.description(&ctx.word_interner);
-                            writeln!(file, "\"{phrase_str}\" : split_words").unwrap();
-                        }
-                    }
-                }
-                if let Lazy::Init(two_typo) = two_typo {
-                    let TwoTypoTerm { two_typos } = two_typo;
-                    for w in two_typos.iter().copied() {
-                        if term_subset.two_typo_subset.contains_word(w) {
-                            let w = ctx.word_interner.get(w);
-                            writeln!(file, "\"{w}\" : 2").unwrap();
-                        }
-                    }
                 }
 
                 writeln!(file, "}}").unwrap();

milli/src/search/new/logger/mod.rs

@@ -1,6 +1,8 @@
 // #[cfg(test)]
 pub mod detailed;
 
+pub mod test_logger;
+
 use roaring::RoaringBitmap;
 
 use super::interner::{Interned, MappedInterner};

milli/src/search/new/mod.rs

@@ -17,6 +17,9 @@ mod sort;
 // TODO: documentation + comments
 mod words;
 
+#[cfg(test)]
+mod tests;
+
 use std::collections::HashSet;
 
 use charabia::TokenizerBuilder;

milli/src/search/new/query_graph.rs

@@ -1,7 +1,6 @@
 use super::interner::{FixedSizeInterner, Interned};
 use super::query_term::{
-    self, number_of_typos_allowed, LocatedQueryTerm, LocatedQueryTermSubset, NTypoTermSubset,
+    self, number_of_typos_allowed, LocatedQueryTerm, LocatedQueryTermSubset, QueryTermSubset,
-    QueryTermSubset,
 };
 use super::small_bitmap::SmallBitmap;
 use super::SearchContext;
@@ -107,12 +106,7 @@ impl QueryGraph {
             let new_node_idx = add_node(
                 &mut nodes_data,
                 QueryNodeData::Term(LocatedQueryTermSubset {
-                    term_subset: QueryTermSubset {
+                    term_subset: QueryTermSubset::full(Interned::from_raw(term_idx as u16)),
-                        original: Interned::from_raw(term_idx as u16),
-                        zero_typo_subset: NTypoTermSubset::All,
-                        one_typo_subset: NTypoTermSubset::All,
-                        two_typo_subset: NTypoTermSubset::All,
-                    },
                     positions: terms[term_idx].positions.clone(),
                     term_ids: term_idx as u8..=term_idx as u8,
                 }),
@@ -126,12 +120,7 @@ impl QueryGraph {
                     let ngram_idx = add_node(
                         &mut nodes_data,
                         QueryNodeData::Term(LocatedQueryTermSubset {
-                            term_subset: QueryTermSubset {
+                            term_subset: QueryTermSubset::full(ngram.value),
-                                original: ngram.value,
-                                zero_typo_subset: NTypoTermSubset::All,
-                                one_typo_subset: NTypoTermSubset::All,
-                                two_typo_subset: NTypoTermSubset::All,
-                            },
                             positions: ngram.positions,
                             term_ids: term_idx as u8 - 1..=term_idx as u8,
                         }),
@@ -146,12 +135,7 @@ impl QueryGraph {
                     let ngram_idx = add_node(
                         &mut nodes_data,
                         QueryNodeData::Term(LocatedQueryTermSubset {
-                            term_subset: QueryTermSubset {
+                            term_subset: QueryTermSubset::full(ngram.value),
-                                original: ngram.value,
-                                zero_typo_subset: NTypoTermSubset::All,
-                                one_typo_subset: NTypoTermSubset::All,
-                                two_typo_subset: NTypoTermSubset::All,
-                            },
                             positions: ngram.positions,
                             term_ids: term_idx as u8 - 2..=term_idx as u8,
                         }),
@@ -329,7 +313,7 @@ impl QueryGraph {
         let mut at_least_one_phrase = false;
         for (node_id, node) in self.nodes.iter() {
             let QueryNodeData::Term(t) = &node.data else { continue };
-            if ctx.term_interner.get(t.term_subset.original).zero_typo.phrase.is_some() {
+            if t.term_subset.original_phrase(ctx).is_some() {
                 at_least_one_phrase = true;
                 continue;
             }

milli/src/search/new/query_term/compute_derivations.rs

@@ -0,0 +1,380 @@
+use fst::automaton::Str;
+use fst::{Automaton, IntoStreamer, Streamer};
+use heed::types::DecodeIgnore;
+use heed::BytesDecode;
+use std::borrow::Cow;
+use std::collections::BTreeSet;
+use std::ops::ControlFlow;
+
+use super::*;
+use crate::search::fst_utils::{Complement, Intersection, StartsWith, Union};
+use crate::search::new::query_term::TwoTypoTerm;
+use crate::search::new::{limits, SearchContext};
+use crate::search::{build_dfa, get_first};
+use crate::{CboRoaringBitmapLenCodec, Result, MAX_WORD_LENGTH};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum NumberOfTypos {
+    Zero,
+    One,
+    Two,
+}
+
+pub enum ZeroOrOneTypo {
+    Zero,
+    One,
+}
+
+impl Interned<QueryTerm> {
+    pub fn compute_fully_if_needed(self, ctx: &mut SearchContext) -> Result<()> {
+        let s = ctx.term_interner.get_mut(self);
+        if s.max_nbr_typos == 0 {
+            s.one_typo = Lazy::Init(OneTypoTerm::default());
+            s.two_typo = Lazy::Init(TwoTypoTerm::default());
+        } else if s.max_nbr_typos == 1 && s.one_typo.is_uninit() {
+            assert!(s.two_typo.is_uninit());
+            self.initialize_one_typo_subterm(ctx)?;
+            let s = ctx.term_interner.get_mut(self);
+            assert!(s.one_typo.is_init());
+            s.two_typo = Lazy::Init(TwoTypoTerm::default());
+        } else if s.max_nbr_typos > 1 && s.two_typo.is_uninit() {
+            assert!(s.two_typo.is_uninit());
+            self.initialize_one_and_two_typo_subterm(ctx)?;
+            let s = ctx.term_interner.get_mut(self);
+            assert!(s.one_typo.is_init() && s.two_typo.is_init());
+        }
+        Ok(())
+    }
+}
+
+fn find_zero_typo_prefix_derivations(
+    word_interned: Interned<String>,
+    fst: fst::Set<Cow<[u8]>>,
+    word_interner: &mut DedupInterner<String>,
+    mut visit: impl FnMut(Interned<String>) -> Result<ControlFlow<()>>,
+) -> Result<()> {
+    let word = word_interner.get(word_interned).to_owned();
+    let word = word.as_str();
+    let prefix = Str::new(word).starts_with();
+    let mut stream = fst.search(prefix).into_stream();
+
+    while let Some(derived_word) = stream.next() {
+        let derived_word = std::str::from_utf8(derived_word)?.to_owned();
+        let derived_word_interned = word_interner.insert(derived_word);
+        if derived_word_interned != word_interned {
+            let cf = visit(derived_word_interned)?;
+            if cf.is_break() {
+                break;
+            }
+        }
+    }
+    Ok(())
+}
+
+fn find_zero_one_typo_derivations(
+    ctx: &mut SearchContext,
+    word_interned: Interned<String>,
+    is_prefix: bool,
+    mut visit: impl FnMut(Interned<String>, ZeroOrOneTypo) -> Result<ControlFlow<()>>,
+) -> Result<()> {
+    let fst = ctx.get_words_fst()?;
+    let word = ctx.word_interner.get(word_interned).to_owned();
+    let word = word.as_str();
+
+    let dfa = build_dfa(word, 1, is_prefix);
+    let starts = StartsWith(Str::new(get_first(word)));
+    let mut stream = fst.search_with_state(Intersection(starts, &dfa)).into_stream();
+
+    while let Some((derived_word, state)) = stream.next() {
+        let derived_word = std::str::from_utf8(derived_word)?;
+        let derived_word = ctx.word_interner.insert(derived_word.to_owned());
+        let d = dfa.distance(state.1);
+        match d.to_u8() {
+            0 => {
+                if derived_word != word_interned {
+                    let cf = visit(derived_word, ZeroOrOneTypo::Zero)?;
+                    if cf.is_break() {
+                        break;
+                    }
+                }
+            }
+            1 => {
+                let cf = visit(derived_word, ZeroOrOneTypo::One)?;
+                if cf.is_break() {
+                    break;
+                }
+            }
+            _ => {
+                unreachable!("One typo dfa produced multiple typos")
+            }
+        }
+    }
+    Ok(())
+}
+
+fn find_zero_one_two_typo_derivations(
+    word_interned: Interned<String>,
+    is_prefix: bool,
+    fst: fst::Set<Cow<[u8]>>,
+    word_interner: &mut DedupInterner<String>,
+    mut visit: impl FnMut(Interned<String>, NumberOfTypos) -> Result<ControlFlow<()>>,
+) -> Result<()> {
+    let word = word_interner.get(word_interned).to_owned();
+    let word = word.as_str();
+
+    let starts = StartsWith(Str::new(get_first(word)));
+    let first = Intersection(build_dfa(word, 1, is_prefix), Complement(&starts));
+    let second_dfa = build_dfa(word, 2, is_prefix);
+    let second = Intersection(&second_dfa, &starts);
+    let automaton = Union(first, &second);
+
+    let mut stream = fst.search_with_state(automaton).into_stream();
+
+    while let Some((derived_word, state)) = stream.next() {
+        let derived_word = std::str::from_utf8(derived_word)?;
+        let derived_word_interned = word_interner.insert(derived_word.to_owned());
+        // in the case the typo is on the first letter, we know the number of typo
+        // is two
+        if get_first(derived_word) != get_first(word) {
+            let cf = visit(derived_word_interned, NumberOfTypos::Two)?;
+            if cf.is_break() {
+                break;
+            }
+        } else {
+            // Else, we know that it is the second dfa that matched and compute the
+            // correct distance
+            let d = second_dfa.distance((state.1).0);
+            match d.to_u8() {
+                0 => {
+                    if derived_word_interned != word_interned {
+                        let cf = visit(derived_word_interned, NumberOfTypos::Zero)?;
+                        if cf.is_break() {
+                            break;
+                        }
+                    }
+                }
+                1 => {
+                    let cf = visit(derived_word_interned, NumberOfTypos::One)?;
+                    if cf.is_break() {
+                        break;
+                    }
+                }
+                2 => {
+                    let cf = visit(derived_word_interned, NumberOfTypos::Two)?;
+                    if cf.is_break() {
+                        break;
+                    }
+                }
+                _ => unreachable!("2 typos DFA produced a distance greater than 2"),
+            }
+        }
+    }
+    Ok(())
+}
+
+pub fn partially_initialized_term_from_word(
+    ctx: &mut SearchContext,
+    word: &str,
+    max_typo: u8,
+    is_prefix: bool,
+) -> Result<QueryTerm> {
+    let word_interned = ctx.word_interner.insert(word.to_owned());
+
+    if word.len() > MAX_WORD_LENGTH {
+        return Ok({
+            QueryTerm {
+                original: ctx.word_interner.insert(word.to_owned()),
+                ngram_words: None,
+                is_prefix: false,
+                max_nbr_typos: 0,
+                zero_typo: <_>::default(),
+                one_typo: Lazy::Init(<_>::default()),
+                two_typo: Lazy::Init(<_>::default()),
+            }
+        });
+    }
+
+    let fst = ctx.index.words_fst(ctx.txn)?;
+
+    let use_prefix_db = is_prefix
+        && ctx
+            .index
+            .word_prefix_docids
+            .remap_data_type::<DecodeIgnore>()
+            .get(ctx.txn, word)?
+            .is_some();
+    let use_prefix_db = if use_prefix_db { Some(word_interned) } else { None };
+
+    let mut zero_typo = None;
+    let mut prefix_of = BTreeSet::new();
+
+    if fst.contains(word) {
+        zero_typo = Some(word_interned);
+    }
+
+    if is_prefix && use_prefix_db.is_none() {
+        find_zero_typo_prefix_derivations(
+            word_interned,
+            fst,
+            &mut ctx.word_interner,
+            |derived_word| {
+                if prefix_of.len() < limits::MAX_PREFIX_COUNT {
+                    prefix_of.insert(derived_word);
+                    Ok(ControlFlow::Continue(()))
+                } else {
+                    Ok(ControlFlow::Break(()))
+                }
+            },
+        )?;
+    }
+    let synonyms = ctx.index.synonyms(ctx.txn)?;
+    let mut synonym_word_count = 0;
+    let synonyms = synonyms
+        .get(&vec![word.to_owned()])
+        .cloned()
+        .unwrap_or_default()
+        .into_iter()
+        .take(limits::MAX_SYNONYM_PHRASE_COUNT)
+        .filter_map(|words| {
+            if synonym_word_count + words.len() > limits::MAX_SYNONYM_WORD_COUNT {
+                return None;
+            }
+            synonym_word_count += words.len();
+            let words = words.into_iter().map(|w| Some(ctx.word_interner.insert(w))).collect();
+            Some(ctx.phrase_interner.insert(Phrase { words }))
+        })
+        .collect();
+    let zero_typo = ZeroTypoTerm { phrase: None, zero_typo, prefix_of, synonyms, use_prefix_db };
+
+    Ok(QueryTerm {
+        original: word_interned,
+        ngram_words: None,
+        max_nbr_typos: max_typo,
+        is_prefix,
+        zero_typo,
+        one_typo: Lazy::Uninit,
+        two_typo: Lazy::Uninit,
+    })
+}
+
+fn find_split_words(ctx: &mut SearchContext, word: &str) -> Result<Option<Interned<Phrase>>> {
+    if let Some((l, r)) = split_best_frequency(ctx, word)? {
+        Ok(Some(ctx.phrase_interner.insert(Phrase { words: vec![Some(l), Some(r)] })))
+    } else {
+        Ok(None)
+    }
+}
+
+impl Interned<QueryTerm> {
+    fn initialize_one_typo_subterm(self, ctx: &mut SearchContext) -> Result<()> {
+        let self_mut = ctx.term_interner.get_mut(self);
+        let QueryTerm { original, is_prefix, one_typo, .. } = self_mut;
+        let original = *original;
+        let is_prefix = *is_prefix;
+        // let original_str = ctx.word_interner.get(*original).to_owned();
+        if one_typo.is_init() {
+            return Ok(());
+        }
+        let mut one_typo_words = BTreeSet::new();
+
+        find_zero_one_typo_derivations(ctx, original, is_prefix, |derived_word, nbr_typos| {
+            match nbr_typos {
+                ZeroOrOneTypo::Zero => {}
+                ZeroOrOneTypo::One => {
+                    if one_typo_words.len() < limits::MAX_ONE_TYPO_COUNT {
+                        one_typo_words.insert(derived_word);
+                    } else {
+                        return Ok(ControlFlow::Break(()));
+                    }
+                }
+            }
+            Ok(ControlFlow::Continue(()))
+        })?;
+        let original_str = ctx.word_interner.get(original).to_owned();
+        let split_words = find_split_words(ctx, original_str.as_str())?;
+        let one_typo = OneTypoTerm { split_words, one_typo: one_typo_words };
+
+        let self_mut = ctx.term_interner.get_mut(self);
+        self_mut.one_typo = Lazy::Init(one_typo);
+
+        Ok(())
+    }
+    fn initialize_one_and_two_typo_subterm(self, ctx: &mut SearchContext) -> Result<()> {
+        let self_mut = ctx.term_interner.get_mut(self);
+        let QueryTerm { original, is_prefix, two_typo, .. } = self_mut;
+        let original_str = ctx.word_interner.get(*original).to_owned();
+        if two_typo.is_init() {
+            return Ok(());
+        }
+        let mut one_typo_words = BTreeSet::new();
+        let mut two_typo_words = BTreeSet::new();
+
+        find_zero_one_two_typo_derivations(
+            *original,
+            *is_prefix,
+            ctx.index.words_fst(ctx.txn)?,
+            &mut ctx.word_interner,
+            |derived_word, nbr_typos| {
+                if one_typo_words.len() >= limits::MAX_ONE_TYPO_COUNT
+                    && two_typo_words.len() >= limits::MAX_TWO_TYPOS_COUNT
+                {
+                    // No chance we will add either one- or two-typo derivations anymore, stop iterating.
+                    return Ok(ControlFlow::Break(()));
+                }
+                match nbr_typos {
+                    NumberOfTypos::Zero => {}
+                    NumberOfTypos::One => {
+                        if one_typo_words.len() < limits::MAX_ONE_TYPO_COUNT {
+                            one_typo_words.insert(derived_word);
+                        }
+                    }
+                    NumberOfTypos::Two => {
+                        if two_typo_words.len() < limits::MAX_TWO_TYPOS_COUNT {
+                            two_typo_words.insert(derived_word);
+                        }
+                    }
+                }
+                Ok(ControlFlow::Continue(()))
+            },
+        )?;
+        let split_words = find_split_words(ctx, original_str.as_str())?;
+        let self_mut = ctx.term_interner.get_mut(self);
+
+        let one_typo = OneTypoTerm { one_typo: one_typo_words, split_words };
+
+        let two_typo = TwoTypoTerm { two_typos: two_typo_words };
+
+        self_mut.one_typo = Lazy::Init(one_typo);
+        self_mut.two_typo = Lazy::Init(two_typo);
+
+        Ok(())
+    }
+}
+
+/// Split the original word into the two words that appear the
+/// most next to each other in the index.
+///
+/// Return `None` if the original word cannot be split.
+fn split_best_frequency(
+    ctx: &mut SearchContext,
+    original: &str,
+) -> Result<Option<(Interned<String>, Interned<String>)>> {
+    let chars = original.char_indices().skip(1);
+    let mut best = None;
+
+    for (i, _) in chars {
+        let (left, right) = original.split_at(i);
+        let left = ctx.word_interner.insert(left.to_owned());
+        let right = ctx.word_interner.insert(right.to_owned());
+
+        if let Some(docid_bytes) = ctx.get_db_word_pair_proximity_docids(left, right, 1)? {
+            let frequency =
+                CboRoaringBitmapLenCodec::bytes_decode(docid_bytes).ok_or(heed::Error::Decoding)?;
+            if best.map_or(true, |(old, _, _)| frequency > old) {
+                best = Some((frequency, left, right));
+            }
+        }
+    }
+
+    Ok(best.map(|(_, left, right)| (left, right)))
+}

milli/src/search/new/query_term/mod.rs

@@ -0,0 +1,331 @@
+mod compute_derivations;
+mod ntypo_subset;
+mod parse_query;
+mod phrase;
+
+use super::interner::{DedupInterner, Interned};
+use super::{limits, SearchContext};
+use crate::Result;
+use std::collections::BTreeSet;
+use std::ops::RangeInclusive;
+
+pub use ntypo_subset::NTypoTermSubset;
+pub use parse_query::{located_query_terms_from_string, make_ngram, number_of_typos_allowed};
+pub use phrase::Phrase;
+
+use compute_derivations::partially_initialized_term_from_word;
+
+/**
+A set of word derivations attached to a location in the search query.
+
+*/
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub struct LocatedQueryTermSubset {
+    pub term_subset: QueryTermSubset,
+    pub positions: RangeInclusive<u16>,
+    pub term_ids: RangeInclusive<u8>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct QueryTermSubset {
+    original: Interned<QueryTerm>,
+    zero_typo_subset: NTypoTermSubset,
+    one_typo_subset: NTypoTermSubset,
+    two_typo_subset: NTypoTermSubset,
+}
+
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub struct QueryTerm {
+    original: Interned<String>,
+    ngram_words: Option<Vec<Interned<String>>>,
+    max_nbr_typos: u8,
+    is_prefix: bool,
+    zero_typo: ZeroTypoTerm,
+    // May not be computed yet
+    one_typo: Lazy<OneTypoTerm>,
+    // May not be computed yet
+    two_typo: Lazy<TwoTypoTerm>,
+}
+
+// SubTerms will be in a dedup interner
+#[derive(Default, Clone, PartialEq, Eq, Hash)]
+struct ZeroTypoTerm {
+    /// The original phrase, if any
+    phrase: Option<Interned<Phrase>>,
+    /// A single word equivalent to the original term, with zero typos
+    zero_typo: Option<Interned<String>>,
+    /// All the words that contain the original word as prefix
+    prefix_of: BTreeSet<Interned<String>>,
+    /// All the synonyms of the original word or phrase
+    synonyms: BTreeSet<Interned<Phrase>>,
+    /// A prefix in the prefix databases matching the original word
+    use_prefix_db: Option<Interned<String>>,
+}
+#[derive(Default, Clone, PartialEq, Eq, Hash)]
+struct OneTypoTerm {
+    /// The original word split into multiple consecutive words
+    split_words: Option<Interned<Phrase>>,
+    /// Words that are 1 typo away from the original word
+    one_typo: BTreeSet<Interned<String>>,
+}
+#[derive(Default, Clone, PartialEq, Eq, Hash)]
+struct TwoTypoTerm {
+    /// Words that are 2 typos away from the original word
+    two_typos: BTreeSet<Interned<String>>,
+}
+
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub enum Lazy<T> {
+    Uninit,
+    Init(T),
+}
+impl<T> Lazy<T> {
+    pub fn is_init(&self) -> bool {
+        match self {
+            Lazy::Uninit => false,
+            Lazy::Init(_) => true,
+        }
+    }
+    pub fn is_uninit(&self) -> bool {
+        match self {
+            Lazy::Uninit => true,
+            Lazy::Init(_) => false,
+        }
+    }
+}
+
+impl QueryTermSubset {
+    pub fn empty(for_term: Interned<QueryTerm>) -> Self {
+        Self {
+            original: for_term,
+            zero_typo_subset: NTypoTermSubset::Nothing,
+            one_typo_subset: NTypoTermSubset::Nothing,
+            two_typo_subset: NTypoTermSubset::Nothing,
+        }
+    }
+    pub fn full(for_term: Interned<QueryTerm>) -> Self {
+        Self {
+            original: for_term,
+            zero_typo_subset: NTypoTermSubset::All,
+            one_typo_subset: NTypoTermSubset::All,
+            two_typo_subset: NTypoTermSubset::All,
+        }
+    }
+
+    pub fn union(&mut self, other: &Self) {
+        assert!(self.original == other.original);
+        self.zero_typo_subset.union(&other.zero_typo_subset);
+        self.one_typo_subset.union(&other.one_typo_subset);
+        self.two_typo_subset.union(&other.two_typo_subset);
+    }
+    pub fn intersect(&mut self, other: &Self) {
+        assert!(self.original == other.original);
+        self.zero_typo_subset.intersect(&other.zero_typo_subset);
+        self.one_typo_subset.intersect(&other.one_typo_subset);
+        self.two_typo_subset.intersect(&other.two_typo_subset);
+    }
+
+    pub fn use_prefix_db(&self, ctx: &SearchContext) -> Option<Interned<String>> {
+        let original = ctx.term_interner.get(self.original);
+        let Some(use_prefix_db) = original.zero_typo.use_prefix_db else {
+            return None
+        };
+        match &self.zero_typo_subset {
+            NTypoTermSubset::All => Some(use_prefix_db),
+            NTypoTermSubset::Subset { words, phrases: _ } => {
+                // TODO: use a subset of prefix words instead
+                if words.contains(&use_prefix_db) {
+                    Some(use_prefix_db)
+                } else {
+                    None
+                }
+            }
+            NTypoTermSubset::Nothing => None,
+        }
+    }
+    pub fn all_single_words_except_prefix_db(
+        &self,
+        ctx: &mut SearchContext,
+    ) -> Result<BTreeSet<Interned<String>>> {
+        let mut result = BTreeSet::default();
+        // TODO: a compute_partially funtion
+        if !self.one_typo_subset.is_empty() || !self.two_typo_subset.is_empty() {
+            self.original.compute_fully_if_needed(ctx)?;
+        }
+
+        let original = ctx.term_interner.get_mut(self.original);
+        if !self.zero_typo_subset.is_empty() {
+            let ZeroTypoTerm { phrase: _, zero_typo, prefix_of, synonyms: _, use_prefix_db: _ } =
+                &original.zero_typo;
+            result.extend(zero_typo.iter().copied());
+            result.extend(prefix_of.iter().copied());
+        };
+
+        match &self.one_typo_subset {
+            NTypoTermSubset::All => {
+                let Lazy::Init(OneTypoTerm { split_words: _, one_typo }) = &original.one_typo else {
+                    panic!()
+                };
+                result.extend(one_typo.iter().copied())
+            }
+            NTypoTermSubset::Subset { words, phrases: _ } => {
+                let Lazy::Init(OneTypoTerm { split_words: _, one_typo }) = &original.one_typo else {
+                    panic!()
+                };
+                result.extend(one_typo.intersection(words));
+            }
+            NTypoTermSubset::Nothing => {}
+        };
+
+        match &self.two_typo_subset {
+            NTypoTermSubset::All => {
+                let Lazy::Init(TwoTypoTerm { two_typos }) = &original.two_typo else {
+                    panic!()
+                };
+                result.extend(two_typos.iter().copied());
+            }
+            NTypoTermSubset::Subset { words, phrases: _ } => {
+                let Lazy::Init(TwoTypoTerm { two_typos }) = &original.two_typo else {
+                    panic!()
+                };
+                result.extend(two_typos.intersection(words));
+            }
+            NTypoTermSubset::Nothing => {}
+        };
+
+        Ok(result)
+    }
+    pub fn all_phrases(&self, ctx: &mut SearchContext) -> Result<BTreeSet<Interned<Phrase>>> {
+        let mut result = BTreeSet::default();
+
+        if !self.one_typo_subset.is_empty() {
+            // TODO: compute less than fully if possible
+            self.original.compute_fully_if_needed(ctx)?;
+        }
+        let original = ctx.term_interner.get_mut(self.original);
+
+        let ZeroTypoTerm { phrase, zero_typo: _, prefix_of: _, synonyms, use_prefix_db: _ } =
+            &original.zero_typo;
+        result.extend(phrase.iter().copied());
+        result.extend(synonyms.iter().copied());
+
+        if !self.one_typo_subset.is_empty() {
+            let Lazy::Init(OneTypoTerm { split_words, one_typo: _ }) = &original.one_typo else {
+                panic!();
+            };
+            result.extend(split_words.iter().copied());
+        }
+
+        Ok(result)
+    }
+
+    pub fn original_phrase(&self, ctx: &SearchContext) -> Option<Interned<Phrase>> {
+        let t = ctx.term_interner.get(self.original);
+        if let Some(p) = t.zero_typo.phrase {
+            if self.zero_typo_subset.contains_phrase(p) {
+                return Some(p);
+            }
+        }
+        None
+    }
+    pub fn max_nbr_typos(&self, ctx: &SearchContext) -> u8 {
+        let t = ctx.term_interner.get(self.original);
+        match t.max_nbr_typos {
+            0 => 0,
+            1 => {
+                if self.one_typo_subset.is_empty() {
+                    0
+                } else {
+                    1
+                }
+            }
+            2 => {
+                if self.two_typo_subset.is_empty() {
+                    if self.one_typo_subset.is_empty() {
+                        0
+                    } else {
+                        1
+                    }
+                } else {
+                    2
+                }
+            }
+            _ => panic!(),
+        }
+    }
+    pub fn clear_zero_typo_subset(&mut self) {
+        self.zero_typo_subset = NTypoTermSubset::Nothing;
+    }
+    pub fn clear_one_typo_subset(&mut self) {
+        self.one_typo_subset = NTypoTermSubset::Nothing;
+    }
+    pub fn clear_two_typo_subset(&mut self) {
+        self.two_typo_subset = NTypoTermSubset::Nothing;
+    }
+    pub fn description(&self, ctx: &SearchContext) -> String {
+        let t = ctx.term_interner.get(self.original);
+        ctx.word_interner.get(t.original).to_owned()
+    }
+}
+
+impl ZeroTypoTerm {
+    fn is_empty(&self) -> bool {
+        let ZeroTypoTerm { phrase, zero_typo, prefix_of, synonyms, use_prefix_db } = self;
+        phrase.is_none()
+            && zero_typo.is_none()
+            && prefix_of.is_empty()
+            && synonyms.is_empty()
+            && use_prefix_db.is_none()
+    }
+}
+impl OneTypoTerm {
+    fn is_empty(&self) -> bool {
+        let OneTypoTerm { split_words, one_typo } = self;
+        one_typo.is_empty() && split_words.is_none()
+    }
+}
+impl TwoTypoTerm {
+    fn is_empty(&self) -> bool {
+        let TwoTypoTerm { two_typos } = self;
+        two_typos.is_empty()
+    }
+}
+
+impl QueryTerm {
+    fn is_empty(&self) -> bool {
+        let Lazy::Init(one_typo) = &self.one_typo else {
+            return false;
+        };
+        let Lazy::Init(two_typo) = &self.two_typo else {
+            return false;
+        };
+
+        self.zero_typo.is_empty() && one_typo.is_empty() && two_typo.is_empty()
+    }
+}
+
+impl Interned<QueryTerm> {
+    /// Return the original word from the given query term
+    fn original_single_word(self, ctx: &SearchContext) -> Option<Interned<String>> {
+        let self_ = ctx.term_interner.get(self);
+        if self_.ngram_words.is_some() {
+            None
+        } else {
+            Some(self_.original)
+        }
+    }
+}
+
+/// A query term coupled with its position in the user's search query.
+#[derive(Clone)]
+pub struct LocatedQueryTerm {
+    pub value: Interned<QueryTerm>,
+    pub positions: RangeInclusive<u16>,
+}
+
+impl LocatedQueryTerm {
+    /// Return `true` iff the term is empty
+    pub fn is_empty(&self, interner: &DedupInterner<QueryTerm>) -> bool {
+        interner.get(self.value).is_empty()
+    }
+}

milli/src/search/new/query_term/ntypo_subset.rs

@@ -0,0 +1,80 @@
+use std::collections::BTreeSet;
+
+use crate::search::new::interner::Interned;
+
+use super::Phrase;
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum NTypoTermSubset {
+    All,
+    Subset {
+        words: BTreeSet<Interned<String>>,
+        phrases: BTreeSet<Interned<Phrase>>,
+        // TODO: prefixes: BTreeSet<Interned<String>>,
+    },
+    Nothing,
+}
+
+impl NTypoTermSubset {
+    pub fn contains_word(&self, word: Interned<String>) -> bool {
+        match self {
+            NTypoTermSubset::All => true,
+            NTypoTermSubset::Subset { words, phrases: _ } => words.contains(&word),
+            NTypoTermSubset::Nothing => false,
+        }
+    }
+    pub fn contains_phrase(&self, phrase: Interned<Phrase>) -> bool {
+        match self {
+            NTypoTermSubset::All => true,
+            NTypoTermSubset::Subset { words: _, phrases } => phrases.contains(&phrase),
+            NTypoTermSubset::Nothing => false,
+        }
+    }
+    pub fn is_empty(&self) -> bool {
+        match self {
+            NTypoTermSubset::All => false,
+            NTypoTermSubset::Subset { words, phrases } => words.is_empty() && phrases.is_empty(),
+            NTypoTermSubset::Nothing => true,
+        }
+    }
+    pub fn union(&mut self, other: &Self) {
+        match self {
+            Self::All => {}
+            Self::Subset { words, phrases } => match other {
+                Self::All => {
+                    *self = Self::All;
+                }
+                Self::Subset { words: w2, phrases: p2 } => {
+                    words.extend(w2);
+                    phrases.extend(p2);
+                }
+                Self::Nothing => {}
+            },
+            Self::Nothing => {
+                *self = other.clone();
+            }
+        }
+    }
+    pub fn intersect(&mut self, other: &Self) {
+        match self {
+            Self::All => *self = other.clone(),
+            Self::Subset { words, phrases } => match other {
+                Self::All => {}
+                Self::Subset { words: w2, phrases: p2 } => {
+                    let mut ws = BTreeSet::new();
+                    for w in words.intersection(w2) {
+                        ws.insert(*w);
+                    }
+                    let mut ps = BTreeSet::new();
+                    for p in phrases.intersection(p2) {
+                        ps.insert(*p);
+                    }
+                    *words = ws;
+                    *phrases = ps;
+                }
+                Self::Nothing => *self = Self::Nothing,
+            },
+            Self::Nothing => {}
+        }
+    }
+}

milli/src/search/new/query_term/parse_query.rs

@@ -0,0 +1,281 @@
+use charabia::{normalizer::NormalizedTokenIter, SeparatorKind, TokenKind};
+
+use crate::{Result, SearchContext, MAX_WORD_LENGTH};
+
+use super::*;
+
+/// Convert the tokenised search query into a list of located query terms.
+// TODO: checking if the positions are correct for phrases, separators, ngrams
+pub fn located_query_terms_from_string(
+    ctx: &mut SearchContext,
+    query: NormalizedTokenIter<&[u8]>,
+    words_limit: Option<usize>,
+) -> Result<Vec<LocatedQueryTerm>> {
+    let nbr_typos = number_of_typos_allowed(ctx)?;
+
+    let mut located_terms = Vec::new();
+
+    let mut phrase: Option<PhraseBuilder> = None;
+
+    let parts_limit = words_limit.unwrap_or(usize::MAX);
+
+    // start with the last position as we will wrap around to position 0 at the beginning of the loop below.
+    let mut position = u16::MAX;
+
+    let mut peekable = query.take(super::limits::MAX_TOKEN_COUNT).peekable();
+    while let Some(token) = peekable.next() {
+        // early return if word limit is exceeded
+        if located_terms.len() >= parts_limit {
+            return Ok(located_terms);
+        }
+
+        match token.kind {
+            TokenKind::Word | TokenKind::StopWord => {
+                // On first loop, goes from u16::MAX to 0, then normal increment.
+                position = position.wrapping_add(1);
+
+                // 1. if the word is quoted we push it in a phrase-buffer waiting for the ending quote,
+                // 2. if the word is not the last token of the query and is not a stop_word we push it as a non-prefix word,
+                // 3. if the word is the last token of the query we push it as a prefix word.
+                if let Some(phrase) = &mut phrase {
+                    phrase.push_word(ctx, &token, position)
+                } else if peekable.peek().is_some() {
+                    match token.kind {
+                        TokenKind::Word => {
+                            let word = token.lemma();
+                            let term = partially_initialized_term_from_word(
+                                ctx,
+                                word,
+                                nbr_typos(word),
+                                false,
+                            )?;
+                            let located_term = LocatedQueryTerm {
+                                value: ctx.term_interner.push(term),
+                                positions: position..=position,
+                            };
+                            located_terms.push(located_term);
+                        }
+                        TokenKind::StopWord | TokenKind::Separator(_) | TokenKind::Unknown => {}
+                    }
+                } else {
+                    let word = token.lemma();
+                    let term =
+                        partially_initialized_term_from_word(ctx, word, nbr_typos(word), true)?;
+                    let located_term = LocatedQueryTerm {
+                        value: ctx.term_interner.push(term),
+                        positions: position..=position,
+                    };
+                    located_terms.push(located_term);
+                }
+            }
+            TokenKind::Separator(separator_kind) => {
+                match separator_kind {
+                    SeparatorKind::Hard => {
+                        position += 1;
+                    }
+                    SeparatorKind::Soft => {
+                        position += 0;
+                    }
+                }
+
+                phrase = 'phrase: {
+                    let phrase = phrase.take();
+
+                    // If we have a hard separator inside a phrase, we immediately start a new phrase
+                    let phrase = if separator_kind == SeparatorKind::Hard {
+                        if let Some(phrase) = phrase {
+                            if let Some(located_query_term) = phrase.build(ctx) {
+                                located_terms.push(located_query_term)
+                            }
+                            Some(PhraseBuilder::empty())
+                        } else {
+                            None
+                        }
+                    } else {
+                        phrase
+                    };
+
+                    // We close and start a new phrase depending on the number of double quotes
+                    let mut quote_count = token.lemma().chars().filter(|&s| s == '"').count();
+                    if quote_count == 0 {
+                        break 'phrase phrase;
+                    }
+
+                    // Consume the closing quote and the phrase
+                    if let Some(phrase) = phrase {
+                        // Per the check above, quote_count > 0
+                        quote_count -= 1;
+                        if let Some(located_query_term) = phrase.build(ctx) {
+                            located_terms.push(located_query_term)
+                        }
+                    }
+
+                    // Start new phrase if the token ends with an opening quote
+                    (quote_count % 2 == 1).then_some(PhraseBuilder::empty())
+                };
+            }
+            _ => (),
+        }
+    }
+
+    // If a quote is never closed, we consider all of the end of the query as a phrase.
+    if let Some(phrase) = phrase.take() {
+        if let Some(located_query_term) = phrase.build(ctx) {
+            located_terms.push(located_query_term);
+        }
+    }
+
+    Ok(located_terms)
+}
+
+pub fn number_of_typos_allowed<'ctx>(
+    ctx: &SearchContext<'ctx>,
+) -> Result<impl Fn(&str) -> u8 + 'ctx> {
+    let authorize_typos = ctx.index.authorize_typos(ctx.txn)?;
+    let min_len_one_typo = ctx.index.min_word_len_one_typo(ctx.txn)?;
+    let min_len_two_typos = ctx.index.min_word_len_two_typos(ctx.txn)?;
+
+    // TODO: should `exact_words` also disable prefix search, ngrams, split words, or synonyms?
+    let exact_words = ctx.index.exact_words(ctx.txn)?;
+
+    Ok(Box::new(move |word: &str| {
+        if !authorize_typos
+            || word.len() < min_len_one_typo as usize
+            || exact_words.as_ref().map_or(false, |fst| fst.contains(word))
+        {
+            0
+        } else if word.len() < min_len_two_typos as usize {
+            1
+        } else {
+            2
+        }
+    }))
+}
+
+pub fn make_ngram(
+    ctx: &mut SearchContext,
+    terms: &[LocatedQueryTerm],
+    number_of_typos_allowed: &impl Fn(&str) -> u8,
+) -> Result<Option<LocatedQueryTerm>> {
+    assert!(!terms.is_empty());
+    for t in terms {
+        if ctx.term_interner.get(t.value).zero_typo.phrase.is_some() {
+            return Ok(None);
+        }
+    }
+    for ts in terms.windows(2) {
+        let [t1, t2] = ts else { panic!() };
+        if *t1.positions.end() != t2.positions.start() - 1 {
+            return Ok(None);
+        }
+    }
+    let mut words_interned = vec![];
+    for term in terms {
+        if let Some(original_term_word) = term.value.original_single_word(ctx) {
+            words_interned.push(original_term_word);
+        } else {
+            return Ok(None);
+        }
+    }
+    let words =
+        words_interned.iter().map(|&i| ctx.word_interner.get(i).to_owned()).collect::<Vec<_>>();
+
+    let start = *terms.first().as_ref().unwrap().positions.start();
+    let end = *terms.last().as_ref().unwrap().positions.end();
+    let is_prefix = ctx.term_interner.get(terms.last().as_ref().unwrap().value).is_prefix;
+    let ngram_str = words.join("");
+    if ngram_str.len() > MAX_WORD_LENGTH {
+        return Ok(None);
+    }
+    let ngram_str_interned = ctx.word_interner.insert(ngram_str.clone());
+
+    let max_nbr_typos =
+        number_of_typos_allowed(ngram_str.as_str()).saturating_sub(terms.len() as u8 - 1);
+
+    let mut term = partially_initialized_term_from_word(ctx, &ngram_str, max_nbr_typos, is_prefix)?;
+
+    // Now add the synonyms
+    let index_synonyms = ctx.index.synonyms(ctx.txn)?;
+
+    term.zero_typo.synonyms.extend(
+        index_synonyms.get(&words).cloned().unwrap_or_default().into_iter().map(|words| {
+            let words = words.into_iter().map(|w| Some(ctx.word_interner.insert(w))).collect();
+            ctx.phrase_interner.insert(Phrase { words })
+        }),
+    );
+
+    let term = QueryTerm {
+        original: ngram_str_interned,
+        ngram_words: Some(words_interned),
+        is_prefix,
+        max_nbr_typos,
+        zero_typo: term.zero_typo,
+        one_typo: Lazy::Uninit,
+        two_typo: Lazy::Uninit,
+    };
+
+    let term = LocatedQueryTerm { value: ctx.term_interner.push(term), positions: start..=end };
+
+    Ok(Some(term))
+}
+
+struct PhraseBuilder {
+    words: Vec<Option<Interned<String>>>,
+    start: u16,
+    end: u16,
+}
+
+impl PhraseBuilder {
+    fn empty() -> Self {
+        Self { words: Default::default(), start: u16::MAX, end: u16::MAX }
+    }
+
+    fn is_empty(&self) -> bool {
+        self.words.is_empty()
+    }
+
+    // precondition: token has kind Word or StopWord
+    fn push_word(&mut self, ctx: &mut SearchContext, token: &charabia::Token, position: u16) {
+        if self.is_empty() {
+            self.start = position;
+        }
+        self.end = position;
+        if let TokenKind::StopWord = token.kind {
+            self.words.push(None);
+        } else {
+            // token has kind Word
+            let word = ctx.word_interner.insert(token.lemma().to_string());
+            // TODO: in a phrase, check that every word exists
+            // otherwise return an empty term
+            self.words.push(Some(word));
+        }
+    }
+
+    fn build(self, ctx: &mut SearchContext) -> Option<LocatedQueryTerm> {
+        if self.is_empty() {
+            return None;
+        }
+        Some(LocatedQueryTerm {
+            value: ctx.term_interner.push({
+                let phrase = ctx.phrase_interner.insert(Phrase { words: self.words });
+                let phrase_desc = phrase.description(ctx);
+                QueryTerm {
+                    original: ctx.word_interner.insert(phrase_desc),
+                    ngram_words: None,
+                    max_nbr_typos: 0,
+                    is_prefix: false,
+                    zero_typo: ZeroTypoTerm {
+                        phrase: Some(phrase),
+                        zero_typo: None,
+                        prefix_of: BTreeSet::default(),
+                        synonyms: BTreeSet::default(),
+                        use_prefix_db: None,
+                    },
+                    one_typo: Lazy::Uninit,
+                    two_typo: Lazy::Uninit,
+                }
+            }),
+            positions: self.start..=self.end,
+        })
+    }
+}

milli/src/search/new/query_term/phrase.rs

@@ -0,0 +1,16 @@
+use itertools::Itertools;
+
+use crate::{search::new::interner::Interned, SearchContext};
+
+/// A phrase in the user's search query, consisting of several words
+/// that must appear side-by-side in the search results.
+#[derive(Default, Clone, PartialEq, Eq, Hash)]
+pub struct Phrase {
+    pub words: Vec<Option<Interned<String>>>,
+}
+impl Interned<Phrase> {
+    pub fn description(self, ctx: &SearchContext) -> String {
+        let p = ctx.phrase_interner.get(self);
+        p.words.iter().flatten().map(|w| ctx.word_interner.get(*w)).join(" ")
+    }
+}

milli/src/search/new/ranking_rule_graph/proximity/mod.rs

@@ -57,9 +57,7 @@ impl RankingRuleGraphTrait for ProximityGraph {
                 Ok(format!("{cost}: cost"))
             }
             ProximityCondition::Term { term } => {
-                let original_term = ctx.term_interner.get(term.term_subset.original);
+                Ok(format!("{} : exists", term.term_subset.description(ctx)))
-                let original_word = ctx.word_interner.get(original_term.original);
-                Ok(format!("{original_word} : exists"))
             }
         }
     }

milli/src/search/new/ranking_rule_graph/typo/mod.rs

@@ -3,7 +3,7 @@ use roaring::RoaringBitmap;
 use super::{ComputedCondition, DeadEndsCache, RankingRuleGraph, RankingRuleGraphTrait};
 use crate::search::new::interner::{DedupInterner, Interned, MappedInterner};
 use crate::search::new::logger::SearchLogger;
-use crate::search::new::query_term::{LocatedQueryTermSubset, NTypoTermSubset};
+use crate::search::new::query_term::LocatedQueryTermSubset;
 use crate::search::new::resolve_query_graph::compute_query_term_subset_docids;
 use crate::search::new::{QueryGraph, QueryNode, SearchContext};
 use crate::Result;
@@ -43,8 +43,7 @@ impl RankingRuleGraphTrait for TypoGraph {
         _from: Option<&LocatedQueryTermSubset>,
         to_term: &LocatedQueryTermSubset,
     ) -> Result<Vec<(u32, Interned<Self::Condition>)>> {
-        let term = to_term; // LocatedQueryTermSubset { term_subset, positions: _, term_ids } = to_term;
+        let term = to_term;
-        let original_full_term = ctx.term_interner.get(term.term_subset.original);
 
         let mut edges = vec![];
         // Ngrams have a base typo cost
@@ -52,20 +51,20 @@ impl RankingRuleGraphTrait for TypoGraph {
         // 3-gram -> equivalent to 2 typos
         let base_cost = if term.term_ids.len() == 1 { 0 } else { term.term_ids.len() as u32 };
 
-        for nbr_typos in 0..=original_full_term.max_nbr_typos {
+        for nbr_typos in 0..=term.term_subset.max_nbr_typos(ctx) {
             let mut term = term.clone();
             match nbr_typos {
                 0 => {
-                    term.term_subset.one_typo_subset = NTypoTermSubset::Nothing;
+                    term.term_subset.clear_one_typo_subset();
-                    term.term_subset.two_typo_subset = NTypoTermSubset::Nothing;
+                    term.term_subset.clear_two_typo_subset();
                 }
                 1 => {
-                    term.term_subset.zero_typo_subset = NTypoTermSubset::Nothing;
+                    term.term_subset.clear_zero_typo_subset();
-                    term.term_subset.two_typo_subset = NTypoTermSubset::Nothing;
+                    term.term_subset.clear_two_typo_subset();
                 }
                 2 => {
-                    term.term_subset.zero_typo_subset = NTypoTermSubset::Nothing;
+                    term.term_subset.clear_zero_typo_subset();
-                    term.term_subset.one_typo_subset = NTypoTermSubset::Nothing;
+                    term.term_subset.clear_one_typo_subset();
                 }
                 _ => panic!(),
             };
@@ -92,9 +91,6 @@ impl RankingRuleGraphTrait for TypoGraph {
 
     fn label_for_condition(ctx: &mut SearchContext, condition: &Self::Condition) -> Result<String> {
         let TypoCondition { term, nbr_typos } = condition;
-        let original_term = ctx.term_interner.get(term.term_subset.original);
+        Ok(format!("{}: {nbr_typos}", term.term_subset.description(ctx)))
-        let original = ctx.word_interner.get(original_term.original);
-
-        Ok(format!("{original}: {nbr_typos}"))
     }
 }