Simplify aggregation

* Update CHANGELOG.md

* Update CHANGELOG.md

CHANGELOG.md

@@ -1,5 +1,14 @@
 
-Tantivy 0.20 [Unreleased]
+Tantivy 0.20.2
+================================
+- Align numerical type priority order on the search side.  [#2088](https://github.com/quickwit-oss/tantivy/issues/2088) (@fmassot)
+- Fix is_child_of function not considering the root facet. [#2086](https://github.com/quickwit-oss/tantivy/issues/2086) (@adamreichhold)
+
+Tantivy 0.20.1
+================================
+- Fix building on windows with mmap [#2070](https://github.com/quickwit-oss/tantivy/issues/2070) (@ChillFish8)
+
+Tantivy 0.20
 ================================
 #### Bugfixes
 - Fix phrase queries with slop (slop supports now transpositions, algorithm that carries slop so far for num terms > 2) [#2031](https://github.com/quickwit-oss/tantivy/issues/2031)[#2020](https://github.com/quickwit-oss/tantivy/issues/2020)(@PSeitz)
@@ -38,12 +47,14 @@ Tantivy 0.20 [Unreleased]
     - Add aggregation support for JSON type [#1888](https://github.com/quickwit-oss/tantivy/issues/1888) (@PSeitz)
     - Mixed types support on JSON fields in aggs [#1971](https://github.com/quickwit-oss/tantivy/issues/1971) (@PSeitz)
   - Perf: Fetch blocks of vals in aggregation for all cardinality [#1950](https://github.com/quickwit-oss/tantivy/issues/1950) (@PSeitz)
+  - Allow histogram bounds to be passed as Rfc3339 [#2076](https://github.com/quickwit-oss/tantivy/issues/2076) (@PSeitz)
 - `Searcher` with disabled scoring via `EnableScoring::Disabled` [#1780](https://github.com/quickwit-oss/tantivy/issues/1780) (@shikhar)
 - Enable tokenizer on json fields [#2053](https://github.com/quickwit-oss/tantivy/issues/2053) (@PSeitz)
 - Enforcing "NOT" and "-" queries consistency in UserInputAst [#1609](https://github.com/quickwit-oss/tantivy/issues/1609) (@bazhenov)
 - Faster indexing
   - Refactor tokenization pipeline to use GATs [#1924](https://github.com/quickwit-oss/tantivy/issues/1924) (@trinity-1686a)
   - Faster term hash map [#2058](https://github.com/quickwit-oss/tantivy/issues/2058)[#1940](https://github.com/quickwit-oss/tantivy/issues/1940) (@PSeitz)
+  - tokenizer-api: reduce Tokenizer allocation overhead [#2062](https://github.com/quickwit-oss/tantivy/issues/2062) (@PSeitz)
   - Refactor vint [#2010](https://github.com/quickwit-oss/tantivy/issues/2010) (@PSeitz)
 - Faster search
   - Work in batches of docs on the SegmentCollector (Only for cases without score for now) [#1937](https://github.com/quickwit-oss/tantivy/issues/1937) (@PSeitz)

Cargo.toml

@@ -23,8 +23,8 @@ once_cell = "1.10.0"
 regex = { version = "1.5.5", default-features = false, features = ["std", "unicode"] }
 aho-corasick = "1.0"
 tantivy-fst = "0.4.0"
-memmap2 = { version = "0.6.0", optional = true }
-lz4_flex = { version = "0.10", default-features = false, features = ["checked-decode"], optional = true }
+memmap2 = { version = "0.7.1", optional = true }
+lz4_flex = { version = "0.11", default-features = false, optional = true }
 brotli = { version = "3.3.4", optional = true }
 zstd = { version = "0.12", optional = true, default-features = false }
 snap = { version = "1.0.5", optional = true }
@@ -51,7 +51,7 @@ smallvec = "1.8.0"
 rayon = "1.5.2"
 lru = "0.10.0"
 fastdivide = "0.4.0"
-itertools = "0.10.3"
+itertools = "0.11.0"
 measure_time = "0.8.2"
 async-trait = "0.1.53"
 arc-swap = "1.5.0"

benches/analyzer.rs

@@ -1,5 +1,7 @@
 use criterion::{criterion_group, criterion_main, Criterion};
-use tantivy::tokenizer::TokenizerManager;
+use tantivy::tokenizer::{
+    LowerCaser, RemoveLongFilter, SimpleTokenizer, TextAnalyzer, TokenizerManager,
+};
 
 const ALICE_TXT: &str = include_str!("alice.txt");
 
@@ -16,7 +18,26 @@ pub fn criterion_benchmark(c: &mut Criterion) {
             assert_eq!(word_count, 30_731);
         })
     });
+    let mut dynamic_analyzer = TextAnalyzer::builder(SimpleTokenizer::default())
+        .dynamic()
+        .filter_dynamic(RemoveLongFilter::limit(40))
+        .filter_dynamic(LowerCaser)
+        .build();
+    c.bench_function("dynamic-tokenize-alice", |b| {
+        b.iter(|| {
+            let mut word_count = 0;
+            let mut token_stream = dynamic_analyzer.token_stream(ALICE_TXT);
+            while token_stream.advance() {
+                word_count += 1;
+            }
+            assert_eq!(word_count, 30_731);
+        })
+    });
 }
 
-criterion_group!(benches, criterion_benchmark);
+criterion_group! {
+    name = benches;
+    config = Criterion::default().sample_size(200);
+    targets = criterion_benchmark
+}
 criterion_main!(benches);

columnar/Cargo.toml

@@ -9,7 +9,7 @@ description = "column oriented storage for tantivy"
 categories = ["database-implementations", "data-structures", "compression"]
 
 [dependencies]
-itertools = "0.10.5"
+itertools = "0.11.0"
 fnv = "1.0.7"
 fastdivide = "0.4.0"
 

columnar/src/column_index/merge/mod.rs

@@ -168,8 +168,9 @@ mod tests {
         )
         .into();
         let merged_column_index = merge_column_index(&column_indexes[..], &merge_row_order);
-        let SerializableColumnIndex::Multivalued(start_index_iterable) = merged_column_index
-        else { panic!("Excpected a multivalued index") };
+        let SerializableColumnIndex::Multivalued(start_index_iterable) = merged_column_index else {
+            panic!("Excpected a multivalued index")
+        };
         let start_indexes: Vec<RowId> = start_index_iterable.boxed_iter().collect();
         assert_eq!(&start_indexes, &[0, 3, 5]);
     }
@@ -200,8 +201,9 @@ mod tests {
         )
         .into();
         let merged_column_index = merge_column_index(&column_indexes[..], &merge_row_order);
-        let SerializableColumnIndex::Multivalued(start_index_iterable) = merged_column_index
-        else { panic!("Excpected a multivalued index") };
+        let SerializableColumnIndex::Multivalued(start_index_iterable) = merged_column_index else {
+            panic!("Excpected a multivalued index")
+        };
         let start_indexes: Vec<RowId> = start_index_iterable.boxed_iter().collect();
         assert_eq!(&start_indexes, &[0, 3, 5, 6]);
     }

columnar/src/column_index/merge/shuffled.rs

@@ -157,7 +157,13 @@ mod tests {
             Cardinality::Optional,
             &shuffle_merge_order,
         );
-        let SerializableColumnIndex::Optional { non_null_row_ids, num_rows } = serializable_index else { panic!() };
+        let SerializableColumnIndex::Optional {
+            non_null_row_ids,
+            num_rows,
+        } = serializable_index
+        else {
+            panic!()
+        };
         assert_eq!(num_rows, 2);
         let non_null_rows: Vec<RowId> = non_null_row_ids.boxed_iter().collect();
         assert_eq!(&non_null_rows, &[1]);

columnar/src/column_values/mod.rs

@@ -2,7 +2,7 @@
 
 //! # `fastfield_codecs`
 //!
-//! - Columnar storage of data for tantivy [`Column`].
+//! - Columnar storage of data for tantivy [`crate::Column`].
 //! - Encode data in different codecs.
 //! - Monotonically map values to u64/u128
 

columnar/src/column_values/u64_based/bitpacked.rs

@@ -83,7 +83,8 @@ impl ColumnValues for BitpackedReader {
         doc_id_range: Range<u32>,
         positions: &mut Vec<u32>,
     ) {
-        let Some(transformed_range) = transform_range_before_linear_transformation(&self.stats, range)
+        let Some(transformed_range) =
+            transform_range_before_linear_transformation(&self.stats, range)
         else {
             positions.clear();
             return;

columnar/src/columnar/merge/merge_mapping.rs

@@ -52,8 +52,8 @@ pub enum MergeRowOrder {
     /// Columnar tables are simply stacked one above the other.
     /// If the i-th columnar_readers has n_rows_i rows, then
     /// in the resulting columnar,
-    /// rows [r0..n_row_0) contains the row of columnar_readers[0], in ordder
-    /// rows [n_row_0..n_row_0 + n_row_1 contains the row of columnar_readers[1], in order.
+    /// rows [r0..n_row_0) contains the row of `columnar_readers[0]`, in ordder
+    /// rows [n_row_0..n_row_0 + n_row_1 contains the row of `columnar_readers[1]`, in order.
     /// ..
     /// No documents is deleted.
     Stack(StackMergeOrder),

columnar/src/columnar/merge/tests.rs

@@ -244,7 +244,9 @@ fn test_merge_columnar_numbers() {
     assert_eq!(columnar_reader.num_columns(), 1);
     let cols = columnar_reader.read_columns("numbers").unwrap();
     let dynamic_column = cols[0].open().unwrap();
-    let DynamicColumn::F64(vals) = dynamic_column else { panic!() };
+    let DynamicColumn::F64(vals) = dynamic_column else {
+        panic!()
+    };
     assert_eq!(vals.get_cardinality(), Cardinality::Optional);
     assert_eq!(vals.first(0u32), Some(-1f64));
     assert_eq!(vals.first(1u32), None);
@@ -270,7 +272,9 @@ fn test_merge_columnar_texts() {
     assert_eq!(columnar_reader.num_columns(), 1);
     let cols = columnar_reader.read_columns("texts").unwrap();
     let dynamic_column = cols[0].open().unwrap();
-    let DynamicColumn::Str(vals) = dynamic_column else { panic!() };
+    let DynamicColumn::Str(vals) = dynamic_column else {
+        panic!()
+    };
     assert_eq!(vals.ords().get_cardinality(), Cardinality::Optional);
 
     let get_str_for_ord = |ord| {
@@ -317,7 +321,9 @@ fn test_merge_columnar_byte() {
     assert_eq!(columnar_reader.num_columns(), 1);
     let cols = columnar_reader.read_columns("bytes").unwrap();
     let dynamic_column = cols[0].open().unwrap();
-    let DynamicColumn::Bytes(vals) = dynamic_column else { panic!() };
+    let DynamicColumn::Bytes(vals) = dynamic_column else {
+        panic!()
+    };
     let get_bytes_for_ord = |ord| {
         let mut out = Vec::new();
         vals.ord_to_bytes(ord, &mut out).unwrap();
@@ -371,7 +377,9 @@ fn test_merge_columnar_byte_with_missing() {
     assert_eq!(columnar_reader.num_columns(), 2);
     let cols = columnar_reader.read_columns("col").unwrap();
     let dynamic_column = cols[0].open().unwrap();
-    let DynamicColumn::Bytes(vals) = dynamic_column else { panic!() };
+    let DynamicColumn::Bytes(vals) = dynamic_column else {
+        panic!()
+    };
     let get_bytes_for_ord = |ord| {
         let mut out = Vec::new();
         vals.ord_to_bytes(ord, &mut out).unwrap();
@@ -423,7 +431,9 @@ fn test_merge_columnar_different_types() {
 
     // numeric column
     let dynamic_column = cols[0].open().unwrap();
-    let DynamicColumn::I64(vals) = dynamic_column else { panic!() };
+    let DynamicColumn::I64(vals) = dynamic_column else {
+        panic!()
+    };
     assert_eq!(vals.get_cardinality(), Cardinality::Optional);
     assert_eq!(vals.values_for_doc(0).collect_vec(), vec![]);
     assert_eq!(vals.values_for_doc(1).collect_vec(), vec![]);
@@ -433,7 +443,9 @@ fn test_merge_columnar_different_types() {
 
     // text column
     let dynamic_column = cols[1].open().unwrap();
-    let DynamicColumn::Str(vals) = dynamic_column else { panic!() };
+    let DynamicColumn::Str(vals) = dynamic_column else {
+        panic!()
+    };
     assert_eq!(vals.ords().get_cardinality(), Cardinality::Optional);
     let get_str_for_ord = |ord| {
         let mut out = String::new();

columnar/src/columnar/writer/mod.rs

@@ -98,9 +98,11 @@ impl ColumnarWriter {
     ///
     /// The sort applied is stable.
     pub fn sort_order(&self, sort_field: &str, num_docs: RowId, reversed: bool) -> Vec<u32> {
-        let Some(numerical_col_writer) =
-            self.numerical_field_hash_map.get::<NumericalColumnWriter>(sort_field.as_bytes()) else {
-                return Vec::new();
+        let Some(numerical_col_writer) = self
+            .numerical_field_hash_map
+            .get::<NumericalColumnWriter>(sort_field.as_bytes())
+        else {
+            return Vec::new();
         };
         let mut symbols_buffer = Vec::new();
         let mut values = Vec::new();

columnar/src/tests.rs

@@ -57,7 +57,9 @@ fn test_dataframe_writer_bool() {
     assert_eq!(cols[0].num_bytes(), 22);
     assert_eq!(cols[0].column_type(), ColumnType::Bool);
     let dyn_bool_col = cols[0].open().unwrap();
-    let DynamicColumn::Bool(bool_col) = dyn_bool_col else { panic!(); };
+    let DynamicColumn::Bool(bool_col) = dyn_bool_col else {
+        panic!();
+    };
     let vals: Vec<Option<bool>> = (0..5).map(|row_id| bool_col.first(row_id)).collect();
     assert_eq!(&vals, &[None, Some(false), None, Some(true), None,]);
 }
@@ -79,7 +81,9 @@ fn test_dataframe_writer_u64_multivalued() {
     assert_eq!(cols.len(), 1);
     assert_eq!(cols[0].num_bytes(), 29);
     let dyn_i64_col = cols[0].open().unwrap();
-    let DynamicColumn::I64(divisor_col) = dyn_i64_col else { panic!(); };
+    let DynamicColumn::I64(divisor_col) = dyn_i64_col else {
+        panic!();
+    };
     assert_eq!(
         divisor_col.get_cardinality(),
         crate::Cardinality::Multivalued
@@ -101,7 +105,9 @@ fn test_dataframe_writer_ip_addr() {
     assert_eq!(cols[0].num_bytes(), 42);
     assert_eq!(cols[0].column_type(), ColumnType::IpAddr);
     let dyn_bool_col = cols[0].open().unwrap();
-    let DynamicColumn::IpAddr(ip_col) = dyn_bool_col else { panic!(); };
+    let DynamicColumn::IpAddr(ip_col) = dyn_bool_col else {
+        panic!();
+    };
     let vals: Vec<Option<Ipv6Addr>> = (0..5).map(|row_id| ip_col.first(row_id)).collect();
     assert_eq!(
         &vals,
@@ -134,7 +140,9 @@ fn test_dataframe_writer_numerical() {
     // - null footer 6 bytes
     assert_eq!(cols[0].num_bytes(), 33);
     let column = cols[0].open().unwrap();
-    let DynamicColumn::I64(column_i64) = column else { panic!(); };
+    let DynamicColumn::I64(column_i64) = column else {
+        panic!();
+    };
     assert_eq!(column_i64.index.get_cardinality(), Cardinality::Optional);
     assert_eq!(column_i64.first(0), None);
     assert_eq!(column_i64.first(1), Some(12i64));
@@ -198,7 +206,9 @@ fn test_dictionary_encoded_str() {
     assert_eq!(columnar_reader.num_columns(), 2);
     let col_handles = columnar_reader.read_columns("my.column").unwrap();
     assert_eq!(col_handles.len(), 1);
-    let DynamicColumn::Str(str_col) = col_handles[0].open().unwrap() else  { panic!(); };
+    let DynamicColumn::Str(str_col) = col_handles[0].open().unwrap() else {
+        panic!();
+    };
     let index: Vec<Option<u64>> = (0..5).map(|row_id| str_col.ords().first(row_id)).collect();
     assert_eq!(index, &[None, Some(0), None, Some(2), Some(1)]);
     assert_eq!(str_col.num_rows(), 5);
@@ -230,7 +240,9 @@ fn test_dictionary_encoded_bytes() {
     assert_eq!(columnar_reader.num_columns(), 2);
     let col_handles = columnar_reader.read_columns("my.column").unwrap();
     assert_eq!(col_handles.len(), 1);
-    let DynamicColumn::Bytes(bytes_col) = col_handles[0].open().unwrap() else  { panic!(); };
+    let DynamicColumn::Bytes(bytes_col) = col_handles[0].open().unwrap() else {
+        panic!();
+    };
     let index: Vec<Option<u64>> = (0..5)
         .map(|row_id| bytes_col.ords().first(row_id))
         .collect();
@@ -533,28 +545,36 @@ trait AssertEqualToColumnValue {
 
 impl AssertEqualToColumnValue for bool {
     fn assert_equal_to_column_value(&self, column_value: &ColumnValue) {
-        let ColumnValue::Bool(val) = column_value else { panic!() };
+        let ColumnValue::Bool(val) = column_value else {
+            panic!()
+        };
         assert_eq!(self, val);
     }
 }
 
 impl AssertEqualToColumnValue for Ipv6Addr {
     fn assert_equal_to_column_value(&self, column_value: &ColumnValue) {
-        let ColumnValue::IpAddr(val) = column_value else { panic!() };
+        let ColumnValue::IpAddr(val) = column_value else {
+            panic!()
+        };
         assert_eq!(self, val);
     }
 }
 
 impl<T: Coerce + PartialEq + Debug + Into<NumericalValue>> AssertEqualToColumnValue for T {
     fn assert_equal_to_column_value(&self, column_value: &ColumnValue) {
-        let ColumnValue::Numerical(num) = column_value else { panic!() };
+        let ColumnValue::Numerical(num) = column_value else {
+            panic!()
+        };
         assert_eq!(self, &T::coerce(*num));
     }
 }
 
 impl AssertEqualToColumnValue for DateTime {
     fn assert_equal_to_column_value(&self, column_value: &ColumnValue) {
-        let ColumnValue::DateTime(dt) = column_value else { panic!() };
+        let ColumnValue::DateTime(dt) = column_value else {
+            panic!()
+        };
         assert_eq!(self, dt);
     }
 }

examples/custom_tokenizer.rs

@@ -53,7 +53,7 @@ fn main() -> tantivy::Result<()> {
     // this will store tokens of 3 characters each
     index
         .tokenizers()
-        .register("ngram3", NgramTokenizer::new(3, 3, false));
+        .register("ngram3", NgramTokenizer::new(3, 3, false).unwrap());
 
     // To insert document we need an index writer.
     // There must be only one writer at a time.

src/aggregation/agg_req_with_accessor.rs

@@ -123,6 +123,15 @@ impl AggregationWithAccessor {
             column_block_accessor: Default::default(),
         })
     }
+
+    /// Swaps the accessor and field type with the second accessor and field type.
+    /// This way we can use the same code for both aggregations.
+    pub(crate) fn swap_accessor(&mut self) {
+        if let Some(accessor) = self.accessor2.as_mut() {
+            std::mem::swap(&mut accessor.0, &mut self.accessor);
+            std::mem::swap(&mut accessor.1, &mut self.field_type);
+        }
+    }
 }
 
 fn get_numeric_or_date_column_types() -> &'static [ColumnType] {

src/aggregation/bucket/mod.rs

@@ -15,6 +15,12 @@
 //! Results of final buckets are [`BucketResult`](super::agg_result::BucketResult).
 //! Results of intermediate buckets are
 //! [`IntermediateBucketResult`](super::intermediate_agg_result::IntermediateBucketResult)
+//!
+//! ## Supported Bucket Aggregations
+//! - [Histogram](HistogramAggregation)
+//! - [DateHistogram](DateHistogramAggregationReq)
+//! - [Range](RangeAggregation)
+//! - [Terms](TermsAggregation)
 
 mod histogram;
 mod range;

src/aggregation/bucket/term_agg.rs

@@ -263,9 +263,9 @@ impl SegmentAggregationCollector for SegmentTermCollectorComposite {
         agg_with_accessor: &mut AggregationsWithAccessor,
     ) -> crate::Result<()> {
         self.term_agg1.collect_block(&[doc], agg_with_accessor)?;
-        self.swap_accessor(&mut agg_with_accessor.aggs.values[self.accessor_idx]);
+        agg_with_accessor.aggs.values[self.accessor_idx].swap_accessor();
         self.term_agg2.collect_block(&[doc], agg_with_accessor)?;
-        self.swap_accessor(&mut agg_with_accessor.aggs.values[self.accessor_idx]);
+        agg_with_accessor.aggs.values[self.accessor_idx].swap_accessor();
         Ok(())
     }
 
@@ -276,33 +276,22 @@ impl SegmentAggregationCollector for SegmentTermCollectorComposite {
         agg_with_accessor: &mut AggregationsWithAccessor,
     ) -> crate::Result<()> {
         self.term_agg1.collect_block(docs, agg_with_accessor)?;
-        self.swap_accessor(&mut agg_with_accessor.aggs.values[self.accessor_idx]);
+        agg_with_accessor.aggs.values[self.accessor_idx].swap_accessor();
         self.term_agg2.collect_block(docs, agg_with_accessor)?;
-        self.swap_accessor(&mut agg_with_accessor.aggs.values[self.accessor_idx]);
-
+        agg_with_accessor.aggs.values[self.accessor_idx].swap_accessor();
         Ok(())
     }
 
     fn flush(&mut self, agg_with_accessor: &mut AggregationsWithAccessor) -> crate::Result<()> {
         self.term_agg1.flush(agg_with_accessor)?;
-        self.swap_accessor(&mut agg_with_accessor.aggs.values[self.accessor_idx]);
+        agg_with_accessor.aggs.values[self.accessor_idx].swap_accessor();
         self.term_agg2.flush(agg_with_accessor)?;
-        self.swap_accessor(&mut agg_with_accessor.aggs.values[self.accessor_idx]);
-
+        agg_with_accessor.aggs.values[self.accessor_idx].swap_accessor();
         Ok(())
     }
 }
 
 impl SegmentTermCollectorComposite {
-    /// Swaps the accessor and field type with the second accessor and field type.
-    /// This way we can use the same code for both aggregations.
-    fn swap_accessor(&self, aggregations: &mut AggregationWithAccessor) {
-        if let Some(accessor) = aggregations.accessor2.as_mut() {
-            std::mem::swap(&mut accessor.0, &mut aggregations.accessor);
-            std::mem::swap(&mut accessor.1, &mut aggregations.field_type);
-        }
-    }
-
     pub(crate) fn from_req_and_validate(
         req: &TermsAggregation,
         sub_aggregations: &mut AggregationsWithAccessor,

src/aggregation/metric/mod.rs

@@ -6,6 +6,15 @@
 //! Some aggregations output a single numeric metric (e.g. Average) and are called
 //! single-value numeric metrics aggregation, others generate multiple metrics (e.g. Stats) and are
 //! called multi-value numeric metrics aggregation.
+//!
+//! ## Supported Metric Aggregations
+//! - [Average](AverageAggregation)
+//! - [Stats](StatsAggregation)
+//! - [Min](MinAggregation)
+//! - [Max](MaxAggregation)
+//! - [Sum](SumAggregation)
+//! - [Count](CountAggregation)
+//! - [Percentiles](PercentilesAggregationReq)
 
 mod average;
 mod count;

src/collector/top_score_collector.rs

@@ -14,7 +14,7 @@ use crate::collector::{
 };
 use crate::fastfield::{FastFieldNotAvailableError, FastValue};
 use crate::query::Weight;
-use crate::{DocAddress, DocId, Score, SegmentOrdinal, SegmentReader, TantivyError};
+use crate::{DocAddress, DocId, Order, Score, SegmentOrdinal, SegmentReader, TantivyError};
 
 struct FastFieldConvertCollector<
     TCollector: Collector<Fruit = Vec<(u64, DocAddress)>>,
@@ -23,6 +23,7 @@ struct FastFieldConvertCollector<
     pub collector: TCollector,
     pub field: String,
     pub fast_value: std::marker::PhantomData<TFastValue>,
+    order: Order,
 }
 
 impl<TCollector, TFastValue> Collector for FastFieldConvertCollector<TCollector, TFastValue>
@@ -70,7 +71,13 @@ where
         let raw_result = self.collector.merge_fruits(segment_fruits)?;
         let transformed_result = raw_result
             .into_iter()
-            .map(|(score, doc_address)| (TFastValue::from_u64(score), doc_address))
+            .map(|(score, doc_address)| {
+                if self.order.is_desc() {
+                    (TFastValue::from_u64(score), doc_address)
+                } else {
+                    (TFastValue::from_u64(u64::MAX - score), doc_address)
+                }
+            })
             .collect::<Vec<_>>();
         Ok(transformed_result)
     }
@@ -131,16 +138,23 @@ impl fmt::Debug for TopDocs {
 
 struct ScorerByFastFieldReader {
     sort_column: Arc<dyn ColumnValues<u64>>,
+    order: Order,
 }
 
 impl CustomSegmentScorer<u64> for ScorerByFastFieldReader {
     fn score(&mut self, doc: DocId) -> u64 {
-        self.sort_column.get_val(doc)
+        let value = self.sort_column.get_val(doc);
+        if self.order.is_desc() {
+            value
+        } else {
+            u64::MAX - value
+        }
     }
 }
 
 struct ScorerByField {
     field: String,
+    order: Order,
 }
 
 impl CustomScorer<u64> for ScorerByField {
@@ -157,8 +171,13 @@ impl CustomScorer<u64> for ScorerByField {
             sort_column_opt.ok_or_else(|| FastFieldNotAvailableError {
                 field_name: self.field.clone(),
             })?;
+        let mut default_value = 0u64;
+        if self.order.is_asc() {
+            default_value = u64::MAX;
+        }
         Ok(ScorerByFastFieldReader {
-            sort_column: sort_column.first_or_default_col(0u64),
+            sort_column: sort_column.first_or_default_col(default_value),
+            order: self.order.clone(),
         })
     }
 }
@@ -230,7 +249,7 @@ impl TopDocs {
     ///
     /// ```rust
     /// # use tantivy::schema::{Schema, FAST, TEXT};
-    /// # use tantivy::{doc, Index, DocAddress};
+    /// # use tantivy::{doc, Index, DocAddress, Order};
     /// # use tantivy::query::{Query, QueryParser};
     /// use tantivy::Searcher;
     /// use tantivy::collector::TopDocs;
@@ -268,7 +287,7 @@ impl TopDocs {
     ///     // Note the `rating_field` needs to be a FAST field here.
     ///     let top_books_by_rating = TopDocs
     ///                 ::with_limit(10)
-    ///                  .order_by_u64_field("rating");
+    ///                  .order_by_fast_field("rating", Order::Desc);
     ///
     ///     // ... and here are our documents. Note this is a simple vec.
     ///     // The `u64` in the pair is the value of our fast field for
@@ -288,13 +307,15 @@ impl TopDocs {
     ///
     /// To comfortably work with `u64`s, `i64`s, `f64`s, or `date`s, please refer to
     /// the [.order_by_fast_field(...)](TopDocs::order_by_fast_field) method.
-    pub fn order_by_u64_field(
+    fn order_by_u64_field(
         self,
         field: impl ToString,
+        order: Order,
     ) -> impl Collector<Fruit = Vec<(u64, DocAddress)>> {
         CustomScoreTopCollector::new(
             ScorerByField {
                 field: field.to_string(),
+                order,
             },
             self.0.into_tscore(),
         )
@@ -316,7 +337,7 @@ impl TopDocs {
     ///
     /// ```rust
     /// # use tantivy::schema::{Schema, FAST, TEXT};
-    /// # use tantivy::{doc, Index, DocAddress};
+    /// # use tantivy::{doc, Index, DocAddress,Order};
     /// # use tantivy::query::{Query, AllQuery};
     /// use tantivy::Searcher;
     /// use tantivy::collector::TopDocs;
@@ -354,7 +375,7 @@ impl TopDocs {
     ///     // type `sort_by_field`. revenue_field here is a FAST i64 field.
     ///     let top_company_by_revenue = TopDocs
     ///                 ::with_limit(2)
-    ///                  .order_by_fast_field("revenue");
+    ///                  .order_by_fast_field("revenue", Order::Desc);
     ///
     ///     // ... and here are our documents. Note this is a simple vec.
     ///     // The `i64` in the pair is the value of our fast field for
@@ -372,15 +393,17 @@ impl TopDocs {
     pub fn order_by_fast_field<TFastValue>(
         self,
         fast_field: impl ToString,
+        order: Order,
     ) -> impl Collector<Fruit = Vec<(TFastValue, DocAddress)>>
     where
         TFastValue: FastValue,
     {
-        let u64_collector = self.order_by_u64_field(fast_field.to_string());
+        let u64_collector = self.order_by_u64_field(fast_field.to_string(), order.clone());
         FastFieldConvertCollector {
             collector: u64_collector,
             field: fast_field.to_string(),
             fast_value: PhantomData,
+            order,
         }
     }
 
@@ -721,7 +744,7 @@ mod tests {
     use crate::schema::{Field, Schema, FAST, STORED, TEXT};
     use crate::time::format_description::well_known::Rfc3339;
     use crate::time::OffsetDateTime;
-    use crate::{DateTime, DocAddress, DocId, Index, IndexWriter, Score, SegmentReader};
+    use crate::{DateTime, DocAddress, DocId, Index, IndexWriter, Order, Score, SegmentReader};
 
     fn make_index() -> crate::Result<Index> {
         let mut schema_builder = Schema::builder();
@@ -882,7 +905,7 @@ mod tests {
         });
         let searcher = index.reader()?.searcher();
 
-        let top_collector = TopDocs::with_limit(4).order_by_u64_field(SIZE);
+        let top_collector = TopDocs::with_limit(4).order_by_u64_field(SIZE, Order::Desc);
         let top_docs: Vec<(u64, DocAddress)> = searcher.search(&query, &top_collector)?;
         assert_eq!(
             &top_docs[..],
@@ -921,7 +944,7 @@ mod tests {
         ))?;
         index_writer.commit()?;
         let searcher = index.reader()?.searcher();
-        let top_collector = TopDocs::with_limit(3).order_by_fast_field("birthday");
+        let top_collector = TopDocs::with_limit(3).order_by_fast_field("birthday", Order::Desc);
         let top_docs: Vec<(DateTime, DocAddress)> = searcher.search(&AllQuery, &top_collector)?;
         assert_eq!(
             &top_docs[..],
@@ -951,7 +974,7 @@ mod tests {
         ))?;
         index_writer.commit()?;
         let searcher = index.reader()?.searcher();
-        let top_collector = TopDocs::with_limit(3).order_by_fast_field("altitude");
+        let top_collector = TopDocs::with_limit(3).order_by_fast_field("altitude", Order::Desc);
         let top_docs: Vec<(i64, DocAddress)> = searcher.search(&AllQuery, &top_collector)?;
         assert_eq!(
             &top_docs[..],
@@ -981,7 +1004,7 @@ mod tests {
         ))?;
         index_writer.commit()?;
         let searcher = index.reader()?.searcher();
-        let top_collector = TopDocs::with_limit(3).order_by_fast_field("altitude");
+        let top_collector = TopDocs::with_limit(3).order_by_fast_field("altitude", Order::Desc);
         let top_docs: Vec<(f64, DocAddress)> = searcher.search(&AllQuery, &top_collector)?;
         assert_eq!(
             &top_docs[..],
@@ -1009,7 +1032,7 @@ mod tests {
                 .unwrap();
         });
         let searcher = index.reader().unwrap().searcher();
-        let top_collector = TopDocs::with_limit(4).order_by_u64_field("missing_field");
+        let top_collector = TopDocs::with_limit(4).order_by_u64_field("missing_field", Order::Desc);
         let segment_reader = searcher.segment_reader(0u32);
         top_collector
             .for_segment(0, segment_reader)
@@ -1027,7 +1050,7 @@ mod tests {
         index_writer.commit()?;
         let searcher = index.reader()?.searcher();
         let segment = searcher.segment_reader(0);
-        let top_collector = TopDocs::with_limit(4).order_by_u64_field(SIZE);
+        let top_collector = TopDocs::with_limit(4).order_by_u64_field(SIZE, Order::Desc);
         let err = top_collector.for_segment(0, segment).err().unwrap();
         assert!(matches!(err, crate::TantivyError::InvalidArgument(_)));
         Ok(())
@@ -1044,7 +1067,7 @@ mod tests {
         index_writer.commit()?;
         let searcher = index.reader()?.searcher();
         let segment = searcher.segment_reader(0);
-        let top_collector = TopDocs::with_limit(4).order_by_fast_field::<i64>(SIZE);
+        let top_collector = TopDocs::with_limit(4).order_by_fast_field::<i64>(SIZE, Order::Desc);
         let err = top_collector.for_segment(0, segment).err().unwrap();
         assert!(
             matches!(err, crate::TantivyError::SchemaError(msg) if msg == "Field \"size\" is not a fast field.")
@@ -1106,4 +1129,50 @@ mod tests {
         let query = query_parser.parse_query(query).unwrap();
         (index, query)
     }
+    #[test]
+    fn test_fast_field_ascending_order() -> crate::Result<()> {
+        let mut schema_builder = Schema::builder();
+        let title = schema_builder.add_text_field(TITLE, TEXT);
+        let size = schema_builder.add_u64_field(SIZE, FAST);
+        let schema = schema_builder.build();
+        let (index, query) = index("beer", title, schema, |index_writer| {
+            index_writer
+                .add_document(doc!(
+                    title => "bottle of beer",
+                    size => 12u64,
+                ))
+                .unwrap();
+            index_writer
+                .add_document(doc!(
+                    title => "growler of beer",
+                    size => 64u64,
+                ))
+                .unwrap();
+            index_writer
+                .add_document(doc!(
+                    title => "pint of beer",
+                    size => 16u64,
+                ))
+                .unwrap();
+            index_writer
+                .add_document(doc!(
+                    title => "empty beer",
+                ))
+                .unwrap();
+        });
+        let searcher = index.reader()?.searcher();
+
+        let top_collector = TopDocs::with_limit(4).order_by_fast_field(SIZE, Order::Asc);
+        let top_docs: Vec<(u64, DocAddress)> = searcher.search(&query, &top_collector)?;
+        assert_eq!(
+            &top_docs[..],
+            &[
+                (12, DocAddress::new(0, 0)),
+                (16, DocAddress::new(0, 2)),
+                (64, DocAddress::new(0, 1)),
+                (18446744073709551615, DocAddress::new(0, 3)),
+            ]
+        );
+        Ok(())
+    }
 }

src/core/json_utils.rs

@@ -259,7 +259,7 @@ pub(crate) fn set_string_and_get_terms(
 
 /// Writes a value of a JSON field to a `Term`.
 /// The Term format is as follows:
-/// [JSON_TYPE][JSON_PATH][JSON_END_OF_PATH][VALUE_BYTES]
+/// `[JSON_TYPE][JSON_PATH][JSON_END_OF_PATH][VALUE_BYTES]`
 pub struct JsonTermWriter<'a> {
     term_buffer: &'a mut Term,
     path_stack: Vec<usize>,

src/fastfield/readers.rs

@@ -88,7 +88,7 @@ impl FastFieldReaders {
         let Some((field, path)): Option<(Field, &str)> = self
             .schema
             .find_field_with_default(field_name, default_field_opt)
-        else{
+        else {
             return Ok(None);
         };
         let field_entry: &FieldEntry = self.schema.get_field_entry(field);
@@ -120,7 +120,8 @@ impl FastFieldReaders {
         T: HasAssociatedColumnType,
         DynamicColumn: Into<Option<Column<T>>>,
     {
-        let Some(dynamic_column_handle) = self.dynamic_column_handle(field_name, T::column_type())?
+        let Some(dynamic_column_handle) =
+            self.dynamic_column_handle(field_name, T::column_type())?
         else {
             return Ok(None);
         };
@@ -196,7 +197,8 @@ impl FastFieldReaders {
 
     /// Returns a `str` column.
     pub fn str(&self, field_name: &str) -> crate::Result<Option<StrColumn>> {
-        let Some(dynamic_column_handle) = self.dynamic_column_handle(field_name, ColumnType::Str)?
+        let Some(dynamic_column_handle) =
+            self.dynamic_column_handle(field_name, ColumnType::Str)?
         else {
             return Ok(None);
         };
@@ -206,7 +208,8 @@ impl FastFieldReaders {
 
     /// Returns a `bytes` column.
     pub fn bytes(&self, field_name: &str) -> crate::Result<Option<BytesColumn>> {
-        let Some(dynamic_column_handle) = self.dynamic_column_handle(field_name, ColumnType::Bytes)?
+        let Some(dynamic_column_handle) =
+            self.dynamic_column_handle(field_name, ColumnType::Bytes)?
         else {
             return Ok(None);
         };

src/indexer/segment_writer.rs

@@ -1,5 +1,6 @@
 use columnar::MonotonicallyMappableToU64;
 use itertools::Itertools;
+use tokenizer_api::BoxTokenStream;
 
 use super::doc_id_mapping::{get_doc_id_mapping_from_field, DocIdMapping};
 use super::operation::AddOperation;
@@ -209,7 +210,7 @@ impl SegmentWriter {
                     for value in values {
                         let mut token_stream = match value {
                             Value::PreTokStr(tok_str) => {
-                                PreTokenizedStream::from(tok_str.clone()).into()
+                                BoxTokenStream::new(PreTokenizedStream::from(tok_str.clone()))
                             }
                             Value::Str(ref text) => {
                                 let text_analyzer =

src/query/more_like_this/more_like_this.rs

@@ -4,9 +4,7 @@ use std::collections::{BinaryHeap, HashMap};
 use crate::query::bm25::idf;
 use crate::query::{BooleanQuery, BoostQuery, Occur, Query, TermQuery};
 use crate::schema::{Field, FieldType, IndexRecordOption, Term, Value};
-use crate::tokenizer::{
-    BoxTokenStream, FacetTokenizer, PreTokenizedStream, TokenStream, Tokenizer,
-};
+use crate::tokenizer::{FacetTokenizer, PreTokenizedStream, TokenStream, Tokenizer};
 use crate::{DocAddress, Result, Searcher, TantivyError};
 
 #[derive(Debug, PartialEq)]
@@ -206,8 +204,7 @@ impl MoreLikeThis {
                 for value in values {
                     match value {
                         Value::PreTokStr(tok_str) => {
-                            let mut token_stream: BoxTokenStream =
-                                PreTokenizedStream::from(tok_str.clone()).into();
+                            let mut token_stream = PreTokenizedStream::from(tok_str.clone());
                             token_stream.process(&mut |token| {
                                 if !self.is_noise_word(token.text.clone()) {
                                     let term = Term::from_field_text(field, &token.text);

src/query/range_query/range_query.rs

@@ -472,6 +472,7 @@ mod tests {
 
     use super::RangeQuery;
     use crate::collector::{Count, TopDocs};
+    use crate::indexer::NoMergePolicy;
     use crate::query::QueryParser;
     use crate::schema::{Document, Field, IntoIpv6Addr, Schema, FAST, INDEXED, STORED, TEXT};
     use crate::{doc, Index};
@@ -547,7 +548,8 @@ mod tests {
 
         let index = Index::create_in_ram(schema);
         {
-            let mut index_writer = index.writer_with_num_threads(2, 60_000_000)?;
+            let mut index_writer = index.writer_with_num_threads(1, 60_000_000)?;
+            index_writer.set_merge_policy(Box::new(NoMergePolicy));
 
             for i in 1..100 {
                 let mut doc = Document::new();
@@ -557,6 +559,9 @@ mod tests {
                     }
                 }
                 index_writer.add_document(doc)?;
+                if i == 10 {
+                    index_writer.commit()?;
+                }
             }
 
             index_writer.commit()?;

src/query/range_query/range_query_ip_fastfield.rs

@@ -31,9 +31,10 @@ impl IPFastFieldRangeWeight {
 
 impl Weight for IPFastFieldRangeWeight {
     fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
-        let Some(ip_addr_column): Option<Column<Ipv6Addr>> = reader.fast_fields()
-            .column_opt(&self.field)? else {
-            return Ok(Box::new(EmptyScorer))
+        let Some(ip_addr_column): Option<Column<Ipv6Addr>> =
+            reader.fast_fields().column_opt(&self.field)?
+        else {
+            return Ok(Box::new(EmptyScorer));
         };
         let value_range = bound_to_value_range(
             &self.lower_bound,

src/query/range_query/range_query_u64_fastfield.rs

@@ -71,7 +71,9 @@ impl Weight for FastFieldRangeWeight {
         let column_type_opt_ref: Option<&[ColumnType]> = column_type_opt
             .as_ref()
             .map(|column_types| column_types.as_slice());
-        let Some((column, _)) = fast_field_reader.u64_lenient_for_type(column_type_opt_ref, &self.field)? else {
+        let Some((column, _)) =
+            fast_field_reader.u64_lenient_for_type(column_type_opt_ref, &self.field)?
+        else {
             return Ok(Box::new(EmptyScorer));
         };
         let value_range = bound_to_value_range(

src/snippet/mod.rs

@@ -693,7 +693,7 @@ Survey in 2016, 2017, and 2018."#;
         terms.insert(String::from("bc"), 1.0);
 
         let fragments = search_fragments(
-            &mut From::from(NgramTokenizer::all_ngrams(2, 2)),
+            &mut From::from(NgramTokenizer::all_ngrams(2, 2).unwrap()),
             text,
             &terms,
             3,

src/store/reader.rs

@@ -426,7 +426,7 @@ mod tests {
         assert_eq!(store.cache_stats().cache_hits, 1);
         assert_eq!(store.cache_stats().cache_misses, 2);
 
-        assert_eq!(store.cache.peek_lru(), Some(11163));
+        assert_eq!(store.cache.peek_lru(), Some(11207));
 
         Ok(())
     }

src/tokenizer/ngram_tokenizer.rs

@@ -1,4 +1,5 @@
 use super::{Token, TokenStream, Tokenizer};
+use crate::TantivyError;
 
 /// Tokenize the text by splitting words into n-grams of the given size(s)
 ///
@@ -33,7 +34,7 @@ use super::{Token, TokenStream, Tokenizer};
 /// ```rust
 /// use tantivy::tokenizer::*;
 ///
-/// let mut tokenizer = NgramTokenizer::new(2, 3, false);
+/// let mut tokenizer = NgramTokenizer::new(2, 3, false).unwrap();
 /// let mut stream = tokenizer.token_stream("hello");
 /// {
 ///     let token = stream.next().unwrap();
@@ -79,7 +80,7 @@ use super::{Token, TokenStream, Tokenizer};
 /// }
 /// assert!(stream.next().is_none());
 /// ```
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct NgramTokenizer {
     /// min size of the n-gram
     min_gram: usize,
@@ -92,30 +93,39 @@ pub struct NgramTokenizer {
 
 impl NgramTokenizer {
     /// Configures a new Ngram tokenizer
-    pub fn new(min_gram: usize, max_gram: usize, prefix_only: bool) -> NgramTokenizer {
-        assert!(min_gram > 0, "min_gram must be greater than 0");
-        assert!(
-            min_gram <= max_gram,
-            "min_gram must not be greater than max_gram"
-        );
-        NgramTokenizer {
+    pub fn new(
+        min_gram: usize,
+        max_gram: usize,
+        prefix_only: bool,
+    ) -> crate::Result<NgramTokenizer> {
+        if min_gram == 0 {
+            return Err(TantivyError::InvalidArgument(
+                "min_gram must be greater than 0".to_string(),
+            ));
+        }
+        if min_gram > max_gram {
+            return Err(TantivyError::InvalidArgument(
+                "min_gram must not be greater than max_gram".to_string(),
+            ));
+        }
+        Ok(NgramTokenizer {
             min_gram,
             max_gram,
             prefix_only,
             token: Token::default(),
-        }
+        })
     }
 
     /// Create a `NGramTokenizer` which generates tokens for all inner ngrams.
     ///
     /// This is as opposed to only prefix ngrams    .
-    pub fn all_ngrams(min_gram: usize, max_gram: usize) -> NgramTokenizer {
+    pub fn all_ngrams(min_gram: usize, max_gram: usize) -> crate::Result<NgramTokenizer> {
         Self::new(min_gram, max_gram, false)
     }
 
     /// Create a `NGramTokenizer` which only generates tokens for the
     /// prefix ngrams.
-    pub fn prefix_only(min_gram: usize, max_gram: usize) -> NgramTokenizer {
+    pub fn prefix_only(min_gram: usize, max_gram: usize) -> crate::Result<NgramTokenizer> {
         Self::new(min_gram, max_gram, true)
     }
 }
@@ -349,7 +359,11 @@ mod tests {
 
     #[test]
     fn test_ngram_tokenizer_1_2_false() {
-        let tokens = test_helper(NgramTokenizer::all_ngrams(1, 2).token_stream("hello"));
+        let tokens = test_helper(
+            NgramTokenizer::all_ngrams(1, 2)
+                .unwrap()
+                .token_stream("hello"),
+        );
         assert_eq!(tokens.len(), 9);
         assert_token(&tokens[0], 0, "h", 0, 1);
         assert_token(&tokens[1], 0, "he", 0, 2);
@@ -364,7 +378,11 @@ mod tests {
 
     #[test]
     fn test_ngram_tokenizer_min_max_equal() {
-        let tokens = test_helper(NgramTokenizer::all_ngrams(3, 3).token_stream("hello"));
+        let tokens = test_helper(
+            NgramTokenizer::all_ngrams(3, 3)
+                .unwrap()
+                .token_stream("hello"),
+        );
         assert_eq!(tokens.len(), 3);
         assert_token(&tokens[0], 0, "hel", 0, 3);
         assert_token(&tokens[1], 0, "ell", 1, 4);
@@ -373,7 +391,11 @@ mod tests {
 
     #[test]
     fn test_ngram_tokenizer_2_5_prefix() {
-        let tokens = test_helper(NgramTokenizer::prefix_only(2, 5).token_stream("frankenstein"));
+        let tokens = test_helper(
+            NgramTokenizer::prefix_only(2, 5)
+                .unwrap()
+                .token_stream("frankenstein"),
+        );
         assert_eq!(tokens.len(), 4);
         assert_token(&tokens[0], 0, "fr", 0, 2);
         assert_token(&tokens[1], 0, "fra", 0, 3);
@@ -383,7 +405,11 @@ mod tests {
 
     #[test]
     fn test_ngram_non_ascii_1_2() {
-        let tokens = test_helper(NgramTokenizer::all_ngrams(1, 2).token_stream("hεllo"));
+        let tokens = test_helper(
+            NgramTokenizer::all_ngrams(1, 2)
+                .unwrap()
+                .token_stream("hεllo"),
+        );
         assert_eq!(tokens.len(), 9);
         assert_token(&tokens[0], 0, "h", 0, 1);
         assert_token(&tokens[1], 0, "hε", 0, 3);
@@ -398,7 +424,11 @@ mod tests {
 
     #[test]
     fn test_ngram_non_ascii_2_5_prefix() {
-        let tokens = test_helper(NgramTokenizer::prefix_only(2, 5).token_stream("hεllo"));
+        let tokens = test_helper(
+            NgramTokenizer::prefix_only(2, 5)
+                .unwrap()
+                .token_stream("hεllo"),
+        );
         assert_eq!(tokens.len(), 4);
         assert_token(&tokens[0], 0, "hε", 0, 3);
         assert_token(&tokens[1], 0, "hεl", 0, 4);
@@ -408,22 +438,26 @@ mod tests {
 
     #[test]
     fn test_ngram_empty() {
-        let tokens = test_helper(NgramTokenizer::all_ngrams(1, 5).token_stream(""));
+        let tokens = test_helper(NgramTokenizer::all_ngrams(1, 5).unwrap().token_stream(""));
         assert!(tokens.is_empty());
-        let tokens = test_helper(NgramTokenizer::all_ngrams(2, 5).token_stream(""));
+        let tokens = test_helper(NgramTokenizer::all_ngrams(2, 5).unwrap().token_stream(""));
         assert!(tokens.is_empty());
     }
 
     #[test]
     #[should_panic(expected = "min_gram must be greater than 0")]
     fn test_ngram_min_max_interval_empty() {
-        test_helper(NgramTokenizer::all_ngrams(0, 2).token_stream("hellossss"));
+        test_helper(
+            NgramTokenizer::all_ngrams(0, 2)
+                .unwrap()
+                .token_stream("hellossss"),
+        );
     }
 
     #[test]
     #[should_panic(expected = "min_gram must not be greater than max_gram")]
     fn test_invalid_interval_should_panic_if_smaller() {
-        NgramTokenizer::all_ngrams(2, 1);
+        NgramTokenizer::all_ngrams(2, 1).unwrap();
     }
 
     #[test]

src/tokenizer/tokenizer.rs

@@ -5,12 +5,32 @@ use tokenizer_api::{BoxTokenStream, TokenFilter, Tokenizer};
 use crate::tokenizer::empty_tokenizer::EmptyTokenizer;
 
 /// `TextAnalyzer` tokenizes an input text into tokens and modifies the resulting `TokenStream`.
+#[derive(Clone)]
 pub struct TextAnalyzer {
     tokenizer: Box<dyn BoxableTokenizer>,
 }
 
+impl Tokenizer for Box<dyn BoxableTokenizer> {
+    type TokenStream<'a> = BoxTokenStream<'a>;
+
+    // Note: we want to call `box_token_stream` on the concrete `Tokenizer`
+    // implementation, not the `BoxableTokenizer` one as it will cause
+    // a recursive call (and a stack overflow).
+    fn token_stream<'a>(&'a mut self, text: &'a str) -> Self::TokenStream<'a> {
+        (**self).box_token_stream(text)
+    }
+}
+
+impl Clone for Box<dyn BoxableTokenizer> {
+    // Note: we want to call `box_clone` on the concrete `Tokenizer`
+    // implementation in order to clone the concrete `Tokenizer`.
+    fn clone(&self) -> Self {
+        (**self).box_clone()
+    }
+}
+
 /// A boxable `Tokenizer`, with its `TokenStream` type erased.
-trait BoxableTokenizer: 'static + Send + Sync {
+pub trait BoxableTokenizer: 'static + Send + Sync {
     /// Creates a boxed token stream for a given `str`.
     fn box_token_stream<'a>(&'a mut self, text: &'a str) -> BoxTokenStream<'a>;
     /// Clone this tokenizer.
@@ -19,21 +39,13 @@ trait BoxableTokenizer: 'static + Send + Sync {
 
 impl<T: Tokenizer> BoxableTokenizer for T {
     fn box_token_stream<'a>(&'a mut self, text: &'a str) -> BoxTokenStream<'a> {
-        self.token_stream(text).into()
+        BoxTokenStream::new(self.token_stream(text))
     }
     fn box_clone(&self) -> Box<dyn BoxableTokenizer> {
         Box::new(self.clone())
     }
 }
 
-impl Clone for TextAnalyzer {
-    fn clone(&self) -> Self {
-        TextAnalyzer {
-            tokenizer: self.tokenizer.box_clone(),
-        }
-    }
-}
-
 impl Default for TextAnalyzer {
     fn default() -> TextAnalyzer {
         TextAnalyzer::from(EmptyTokenizer)
@@ -54,12 +66,12 @@ impl TextAnalyzer {
 
     /// Creates a token stream for a given `str`.
     pub fn token_stream<'a>(&'a mut self, text: &'a str) -> BoxTokenStream<'a> {
-        self.tokenizer.box_token_stream(text)
+        self.tokenizer.token_stream(text)
     }
 }
 
 /// Builder helper for [`TextAnalyzer`]
-pub struct TextAnalyzerBuilder<T> {
+pub struct TextAnalyzerBuilder<T = Box<dyn BoxableTokenizer>> {
     tokenizer: T,
 }
 
@@ -83,6 +95,23 @@ impl<T: Tokenizer> TextAnalyzerBuilder<T> {
         }
     }
 
+    /// Boxes the internal tokenizer. This is useful for adding dynamic filters.
+    /// Note: this will be less performant than the non boxed version.
+    pub fn dynamic(self) -> TextAnalyzerBuilder {
+        let boxed_tokenizer = Box::new(self.tokenizer);
+        TextAnalyzerBuilder {
+            tokenizer: boxed_tokenizer,
+        }
+    }
+
+    /// Appends a token filter to the current builder and returns a boxed version of the
+    /// tokenizer. This is useful when you want to build a `TextAnalyzer` dynamically.
+    /// Prefer using `TextAnalyzer::builder(tokenizer).filter(token_filter).build()` if
+    /// possible as it will be more performant and create less boxes.
+    pub fn filter_dynamic<F: TokenFilter>(self, token_filter: F) -> TextAnalyzerBuilder {
+        self.filter(token_filter).dynamic()
+    }
+
     /// Finalize building the TextAnalyzer
     pub fn build(self) -> TextAnalyzer {
         TextAnalyzer {
@@ -90,3 +119,57 @@ impl<T: Tokenizer> TextAnalyzerBuilder<T> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+    use crate::tokenizer::{LowerCaser, RemoveLongFilter, SimpleTokenizer};
+
+    #[test]
+    fn test_text_analyzer_builder() {
+        let mut analyzer = TextAnalyzer::builder(SimpleTokenizer::default())
+            .filter(RemoveLongFilter::limit(40))
+            .filter(LowerCaser)
+            .build();
+        let mut stream = analyzer.token_stream("- first bullet point");
+        assert_eq!(stream.next().unwrap().text, "first");
+        assert_eq!(stream.next().unwrap().text, "bullet");
+    }
+
+    #[test]
+    fn test_text_analyzer_with_filters_boxed() {
+        // This test shows how one can build a TextAnalyzer dynamically, by stacking a list
+        // of parametrizable token filters.
+        //
+        // The following enum is the thing that would be serializable.
+        // Note that token filters can have their own parameters, too, like the RemoveLongFilter
+        enum SerializableTokenFilterEnum {
+            LowerCaser(LowerCaser),
+            RemoveLongFilter(RemoveLongFilter),
+        }
+        // Note that everything below is dynamic.
+        let filters: Vec<SerializableTokenFilterEnum> = vec![
+            SerializableTokenFilterEnum::LowerCaser(LowerCaser),
+            SerializableTokenFilterEnum::RemoveLongFilter(RemoveLongFilter::limit(12)),
+        ];
+        let mut analyzer_builder: TextAnalyzerBuilder =
+            TextAnalyzer::builder(SimpleTokenizer::default())
+                .filter_dynamic(RemoveLongFilter::limit(40))
+                .filter_dynamic(LowerCaser);
+        for filter in filters {
+            analyzer_builder = match filter {
+                SerializableTokenFilterEnum::LowerCaser(lower_caser) => {
+                    analyzer_builder.filter_dynamic(lower_caser)
+                }
+                SerializableTokenFilterEnum::RemoveLongFilter(remove_long_filter) => {
+                    analyzer_builder.filter_dynamic(remove_long_filter)
+                }
+            }
+        }
+        let mut analyzer = analyzer_builder.build();
+        let mut stream = analyzer.token_stream("first bullet point");
+        assert_eq!(stream.next().unwrap().text, "first");
+        assert_eq!(stream.next().unwrap().text, "bullet");
+    }
+}

tokenizer-api/src/lib.rs

@@ -63,10 +63,22 @@ pub trait Tokenizer: 'static + Clone + Send + Sync {
 /// Simple wrapper of `Box<dyn TokenStream + 'a>`.
 pub struct BoxTokenStream<'a>(Box<dyn TokenStream + 'a>);
 
-impl<'a, T> From<T> for BoxTokenStream<'a>
-where T: TokenStream + 'a
-{
-    fn from(token_stream: T) -> BoxTokenStream<'a> {
+impl<'a> TokenStream for BoxTokenStream<'a> {
+    fn advance(&mut self) -> bool {
+        self.0.advance()
+    }
+
+    fn token(&self) -> &Token {
+        self.0.token()
+    }
+
+    fn token_mut(&mut self) -> &mut Token {
+        self.0.token_mut()
+    }
+}
+
+impl<'a> BoxTokenStream<'a> {
+    pub fn new<T: TokenStream + 'a>(token_stream: T) -> BoxTokenStream<'a> {
         BoxTokenStream(Box::new(token_stream))
     }
 }