Introduce RelResult rather than Vec<Vec<TypedValue>>. (#639) r=nalexander

* Pre: clean up core/src/lib.rs.
* Pre: use indexmap 1.0 in db and query-projector.
* Change rel results to be a RelResult instance, not a Vec<Vec<TypedValue>>.

This avoids memory fragmentation and improves locality by using a single
heap-allocated vector for all bindings, rather than a separate
heap-allocated vector for each row.

We hide this abstraction behind the `RelResult` type, which tracks the
stride length (width) of each row.

* Don't allocate temporary vectors when projecting RelResults.

core/src/lib.rs

@@ -183,8 +183,9 @@ impl fmt::Display for ValueType {
 }
 
 /// Represents a Mentat value in a particular value set.
-// TODO: expand to include :db.type/{instant,url,uuid}.
+// TODO: expand to include :db.type/uri. https://github.com/mozilla/mentat/issues/201
-// TODO: BigInt?
+// TODO: JSON data type? https://github.com/mozilla/mentat/issues/31
+// TODO: BigInt? Bytes?
 #[derive(Clone,Debug,Eq,Hash,Ord,PartialOrd,PartialEq,Serialize,Deserialize)]
 pub enum TypedValue {
     Ref(Entid),
@@ -983,6 +984,10 @@ impl HasSchema for Schema {
     }
 }
 
+pub mod intern_set;
+pub mod counter;
+pub mod util;
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -1125,7 +1130,3 @@ mod test {
         assert_eq!(expected_value, value2);
     }
 }
-
-pub mod intern_set;
-pub mod counter;
-pub mod util;

db/Cargo.toml

@@ -5,7 +5,7 @@ workspace = ".."
 
 [dependencies]
 error-chain = { git = "https://github.com/rnewman/error-chain", branch = "rnewman/sync" }
-indexmap = "0.4"
+indexmap = "1"
 itertools = "0.7"
 lazy_static = "0.2"
 num = "0.1"

query-projector/Cargo.toml

@@ -5,7 +5,7 @@ workspace = ".."
 
 [dependencies]
 error-chain = { git = "https://github.com/rnewman/error-chain", branch = "rnewman/sync" }
-indexmap = "0.4"
+indexmap = "1"
 
 [dependencies.rusqlite]
 version = "0.13"

query-projector/src/lib.rs

@@ -66,6 +66,7 @@ use mentat_query_sql::{
 
 mod aggregates;
 mod project;
+mod relresult;
 pub mod errors;
 
 pub use aggregates::{
@@ -81,6 +82,10 @@ pub use project::{
     projected_column_for_var,
 };
 
+pub use relresult::{
+    RelResult,
+};
+
 use errors::{
     ErrorKind,
     Result,
@@ -97,7 +102,7 @@ pub enum QueryResults {
     Scalar(Option<TypedValue>),
     Tuple(Option<Vec<TypedValue>>),
     Coll(Vec<TypedValue>),
-    Rel(Vec<Vec<TypedValue>>),
+    Rel(RelResult),
 }
 
 impl From<QueryOutput> for QueryResults {
@@ -113,7 +118,10 @@ impl QueryOutput {
             &FindScalar(_)   => Box::new(|| QueryResults::Scalar(None)),
             &FindTuple(_)    => Box::new(|| QueryResults::Tuple(None)),
             &FindColl(_)     => Box::new(|| QueryResults::Coll(vec![])),
-            &FindRel(_)    => Box::new(|| QueryResults::Rel(vec![])),
+            &FindRel(ref es) => {
+                let width = es.len();
+                Box::new(move || QueryResults::Rel(RelResult::empty(width)))
+            },
         }
     }
 
@@ -132,7 +140,7 @@ impl QueryOutput {
                 &FindScalar(_)   => QueryResults::Scalar(None),
                 &FindTuple(_)    => QueryResults::Tuple(None),
                 &FindColl(_)     => QueryResults::Coll(vec![]),
-                &FindRel(_)    => QueryResults::Rel(vec![]),
+                &FindRel(ref es) => QueryResults::Rel(RelResult::empty(es.len())),
             };
         QueryOutput {
             spec: spec.clone(),
@@ -181,6 +189,7 @@ impl QueryOutput {
                 unimplemented!();
             },
             &FindRel(ref elements) => {
+                let width = elements.len();
                 let values = elements.iter().map(|e| match e {
                     &Element::Variable(ref var) |
                     &Element::Corresponding(ref var) => {
@@ -192,7 +201,7 @@ impl QueryOutput {
                         unreachable!();
                     },
                 }).collect();
-                QueryResults::Rel(vec![values])
+                QueryResults::Rel(RelResult { width, values })
             },
         }
     }
@@ -209,7 +218,7 @@ impl QueryOutput {
         self.results.into_tuple()
     }
 
-    pub fn into_rel(self) -> Result<Vec<Vec<TypedValue>>> {
+    pub fn into_rel(self) -> Result<RelResult> {
         self.results.into_rel()
     }
 }
@@ -221,7 +230,7 @@ impl QueryResults {
             &Scalar(ref o) => if o.is_some() { 1 } else { 0 },
             &Tuple(ref o)  => if o.is_some() { 1 } else { 0 },
             &Coll(ref v)   => v.len(),
-            &Rel(ref v)    => v.len(),
+            &Rel(ref r)    => r.row_count(),
         }
     }
 
@@ -231,7 +240,7 @@ impl QueryResults {
             &Scalar(ref o) => o.is_none(),
             &Tuple(ref o)  => o.is_none(),
             &Coll(ref v)   => v.is_empty(),
-            &Rel(ref v)    => v.is_empty(),
+            &Rel(ref r)    => r.is_empty(),
         }
     }
 
@@ -262,7 +271,7 @@ impl QueryResults {
         }
     }
 
-    pub fn into_rel(self) -> Result<Vec<Vec<TypedValue>>> {
+    pub fn into_rel(self) -> Result<RelResult> {
         match self {
             QueryResults::Scalar(_) => bail!(ErrorKind::UnexpectedResultsType("scalar", "rel")),
             QueryResults::Coll(_) => bail!(ErrorKind::UnexpectedResultsType("coll", "rel")),
@@ -457,10 +466,9 @@ impl Projector for TupleProjector {
     }
 }
 
-/// A rel projector produces a vector of vectors.
+/// A rel projector produces a RelResult, which is a striding abstraction over a vector.
-/// Each inner vector is the same size, and sourced from the same columns.
+/// Each stride across the vector is the same size, and sourced from the same columns.
-/// One inner vector is produced per `Row`.
+/// Each column in each stride is the result of taking one or two columns from
-/// Each column in the inner vector is the result of taking one or two columns from
 /// the `Row`: one for the value and optionally one for the type tag.
 struct RelProjector {
     spec: Rc<FindSpec>,
@@ -477,15 +485,20 @@ impl RelProjector {
         }
     }
 
-    fn collect_bindings<'a, 'stmt>(&self, row: Row<'a, 'stmt>) -> Result<Vec<TypedValue>> {
+    fn collect_bindings_into<'a, 'stmt, 'out>(&self, row: Row<'a, 'stmt>, out: &mut Vec<TypedValue>) -> Result<()> {
         // There will be at least as many SQL columns as Datalog columns.
         // gte 'cos we might be querying extra columns for ordering.
         // The templates will take care of ignoring columns.
         assert!(row.column_count() >= self.len as i32);
-        self.templates
+        let mut count = 0;
+        for binding in self.templates
                            .iter()
-            .map(|ti| ti.lookup(&row))
+                           .map(|ti| ti.lookup(&row)) {
-            .collect::<Result<Vec<TypedValue>>>()
+            out.push(binding?);
+            count += 1;
+        }
+        assert_eq!(self.len, count);
+        Ok(())
     }
 
     fn combine(spec: Rc<FindSpec>, column_count: usize, elements: ProjectedElements) -> Result<CombinedProjection> {
@@ -509,15 +522,19 @@ impl RelProjector {
 
 impl Projector for RelProjector {
     fn project<'stmt>(&self, mut rows: Rows<'stmt>) -> Result<QueryOutput> {
-        let mut out: Vec<Vec<TypedValue>> = vec![];
+        // Allocate space for five rows to start.
+        // This is better than starting off by doubling the buffer a couple of times, and will
+        // rapidly grow to support larger query results.
+        let width = self.len;
+        let mut values: Vec<_> = Vec::with_capacity(5 * width);
+
         while let Some(r) = rows.next() {
             let row = r?;
-            let bindings = self.collect_bindings(row)?;
+            self.collect_bindings_into(row, &mut values)?;
-            out.push(bindings);
         }
         Ok(QueryOutput {
             spec: self.spec.clone(),
-            results: QueryResults::Rel(out),
+            results: QueryResults::Rel(RelResult { width, values }),
         })
     }
 

query-projector/src/relresult.rs

@@ -0,0 +1,150 @@
+// Copyright 2018 Mozilla
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+// this file except in compliance with the License. You may obtain a copy of the
+// License at http://www.apache.org/licenses/LICENSE-2.0
+// Unless required by applicable law or agreed to in writing, software distributed
+// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations under the License.
+
+use mentat_core::{
+    TypedValue,
+};
+
+/// The result you get from a 'rel' query, like:
+///
+/// ```edn
+/// [:find ?person ?name
+///  :where [?person :person/name ?name]]
+/// ```
+///
+/// There are three ways to get data out of a `RelResult`:
+/// - By iterating over rows as slices. Use `result.rows()`. This is efficient and is
+///   recommended in two cases:
+///   1. If you don't need to take ownership of the resulting values (e.g., you're comparing
+///      or making a modified clone).
+///   2. When the data you're retrieving is cheap to clone. All scalar values are relatively
+///      cheap: they're either small values or `Rc`.
+/// - By direct reference to a row by index, using `result.row(i)`. This also returns
+///   a reference.
+/// - By consuming the results using `into_iter`. This allocates short-lived vectors,
+///   but gives you ownership of the enclosed `TypedValue`s.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct RelResult {
+    pub width: usize,
+    pub values: Vec<TypedValue>,
+}
+
+impl RelResult {
+    pub fn empty(width: usize) -> RelResult {
+        RelResult {
+            width: width,
+            values: Vec::new(),
+        }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.values.is_empty()
+    }
+
+    pub fn row_count(&self) -> usize {
+        self.values.len() / self.width
+    }
+
+    pub fn rows(&self) -> ::std::slice::Chunks<TypedValue> {
+        // TODO: Nightly-only API `exact_chunks`. #47115.
+        self.values.chunks(self.width)
+    }
+
+    pub fn row(&self, index: usize) -> Option<&[TypedValue]> {
+        let end = self.width * (index + 1);
+        if end > self.values.len() {
+            None
+        } else {
+            let start = self.width * index;
+            Some(&self.values[start..end])
+        }
+    }
+}
+
+#[test]
+fn test_rel_result() {
+    let empty = RelResult::empty(3);
+    let unit = RelResult {
+        width: 1,
+        values: vec![TypedValue::Long(5)],
+    };
+    let two_by_two = RelResult {
+        width: 2,
+        values: vec![TypedValue::Long(5), TypedValue::Boolean(true),
+                     TypedValue::Long(-2), TypedValue::Boolean(false)],
+    };
+
+    assert!(empty.is_empty());
+    assert!(!unit.is_empty());
+    assert!(!two_by_two.is_empty());
+
+    assert_eq!(empty.row_count(), 0);
+    assert_eq!(unit.row_count(), 1);
+    assert_eq!(two_by_two.row_count(), 2);
+
+    assert_eq!(empty.row(0), None);
+    assert_eq!(unit.row(1), None);
+    assert_eq!(two_by_two.row(2), None);
+
+    assert_eq!(unit.row(0), Some(vec![TypedValue::Long(5)].as_slice()));
+    assert_eq!(two_by_two.row(0), Some(vec![TypedValue::Long(5), TypedValue::Boolean(true)].as_slice()));
+    assert_eq!(two_by_two.row(1), Some(vec![TypedValue::Long(-2), TypedValue::Boolean(false)].as_slice()));
+
+    let mut rr = two_by_two.rows();
+    assert_eq!(rr.next(), Some(vec![TypedValue::Long(5), TypedValue::Boolean(true)].as_slice()));
+    assert_eq!(rr.next(), Some(vec![TypedValue::Long(-2), TypedValue::Boolean(false)].as_slice()));
+    assert_eq!(rr.next(), None);
+}
+
+// Primarily for testing.
+impl From<Vec<Vec<TypedValue>>> for RelResult {
+    fn from(src: Vec<Vec<TypedValue>>) -> Self {
+        if src.is_empty() {
+            RelResult::empty(0)
+        } else {
+            let width = src.get(0).map(|r| r.len()).unwrap_or(0);
+            RelResult {
+                width: width,
+                values: src.into_iter().flat_map(|r| r.into_iter()).collect(),
+            }
+        }
+    }
+}
+
+pub struct SubvecIntoIterator {
+    width: usize,
+    values: ::std::vec::IntoIter<TypedValue>,
+}
+
+impl Iterator for SubvecIntoIterator {
+    // TODO: this is a good opportunity to use `SmallVec` instead: most queries
+    // return a handful of columns.
+    type Item = Vec<TypedValue>;
+    fn next(&mut self) -> Option<Vec<TypedValue>> {
+        let result: Vec<TypedValue> = (&mut self.values).take(self.width).collect();
+        if result.is_empty() {
+            None
+        } else {
+            Some(result)
+        }
+    }
+}
+
+impl IntoIterator for RelResult {
+    type Item = Vec<TypedValue>;
+    type IntoIter = SubvecIntoIterator;
+
+    fn into_iter(self) -> Self::IntoIter {
+        SubvecIntoIterator {
+            width: self.width,
+            values: self.values.into_iter(),
+        }
+    }
+}

query-translator/tests/translate.rs

@@ -755,7 +755,7 @@ fn test_ground_tuple() {
     let constant = translate_to_constant(&schema, query);
     assert_eq!(constant.project_without_rows().unwrap()
                        .into_rel().unwrap(),
-               vec![vec![TypedValue::Long(1), TypedValue::typed_string("yyy")]]);
+               vec![vec![TypedValue::Long(1), TypedValue::typed_string("yyy")]].into());
 
     // Verify that we accept bound input constants.
     let query = r#"[:find [?x ?y] :in ?u ?v :where [(ground [?u ?v]) [?x ?y]]]"#;

query/src/lib.rs

@@ -558,7 +558,7 @@ pub enum Limit {
 ///
 #[derive(Debug, Eq, PartialEq)]
 pub enum FindSpec {
-    /// Returns an array of arrays.
+    /// Returns an array of arrays, represented as a single array with length a multiple of width.
     FindRel(Vec<Element>),
 
     /// Returns an array of scalars, usually homogeneous.

src/conn.rs

@@ -1358,7 +1358,7 @@ mod tests {
         let end = time::PreciseTime::now();
         println!("Prepared cache execution took {}µs", start.to(end).num_microseconds().unwrap());
         assert_eq!(results.into_rel().expect("result"),
-                   vec![vec![TypedValue::typed_string("Greater Duwamish")]]);
+                   vec![vec![TypedValue::typed_string("Greater Duwamish")]].into());
     }
 
     trait StoreCache {

src/lib.rs

@@ -108,6 +108,7 @@ pub use query::{
     QueryOutput,
     QueryPlanStep,
     QueryResults,
+    RelResult,
     Variable,
     q_once,
 };

src/query.rs

@@ -72,6 +72,7 @@ pub use mentat_query_algebrizer::{
 pub use mentat_query_projector::{
     QueryOutput,        // Includes the columns/find spec.
     QueryResults,       // The results themselves.
+    RelResult,
 };
 
 use errors::{
@@ -119,7 +120,7 @@ pub trait IntoResult {
     fn into_scalar_result(self) -> Result<Option<TypedValue>>;
     fn into_coll_result(self) -> Result<Vec<TypedValue>>;
     fn into_tuple_result(self) -> Result<Option<Vec<TypedValue>>>;
-    fn into_rel_result(self) -> Result<Vec<Vec<TypedValue>>>;
+    fn into_rel_result(self) -> Result<RelResult>;
 }
 
 impl IntoResult for QueryExecutionResult {
@@ -135,7 +136,7 @@ impl IntoResult for QueryExecutionResult {
         self?.into_tuple().map_err(|e| e.into())
     }
 
-    fn into_rel_result(self) -> Result<Vec<Vec<TypedValue>>> {
+    fn into_rel_result(self) -> Result<RelResult> {
         self?.into_rel().map_err(|e| e.into())
     }
 }

src/query_builder.rs

@@ -25,6 +25,7 @@ use ::{
     Queryable,
     QueryInputs,
     QueryOutput,
+    RelResult,
     Store,
     Variable,
 };
@@ -100,7 +101,7 @@ impl<'a> QueryBuilder<'a> {
         results.into_tuple().map_err(|e| e.into())
     }
 
-    pub fn execute_rel(&mut self) -> Result<Vec<Vec<TypedValue>>> {
+    pub fn execute_rel(&mut self) -> Result<RelResult> {
         let results = self.execute()?;
         results.into_rel().map_err(|e| e.into())
     }

tests/query.rs

@@ -48,6 +48,7 @@ use mentat::{
     QueryInputs,
     Queryable,
     QueryResults,
+    RelResult,
     Store,
     TxReport,
     Variable,
@@ -80,8 +81,8 @@ fn test_rel() {
     assert_eq!(40, results.len());
 
     // Every row is a pair of a Ref and a Keyword.
-    if let QueryResults::Rel(ref rel) = results {
+    if let QueryResults::Rel(rel) = results {
-        for r in rel {
+        for r in rel.into_iter() {
             assert_eq!(r.len(), 2);
             assert!(r[0].matches_type(ValueType::Ref));
             assert!(r[1].matches_type(ValueType::Keyword));
@@ -90,7 +91,6 @@ fn test_rel() {
         panic!("Expected rel.");
     }
 
-    println!("{:?}", results);
     println!("Rel took {}µs", start.to(end).num_microseconds().unwrap());
 }
 
@@ -309,7 +309,7 @@ fn test_tx() {
         QueryResults::Rel(ref v) => {
             assert_eq!(*v, vec![
                 vec![TypedValue::Ref(t.tx_id),]
-            ]);
+            ].into());
         },
         _ => panic!("Expected query to work."),
     }
@@ -346,7 +346,7 @@ fn test_tx_as_input() {
         QueryResults::Rel(ref v) => {
             assert_eq!(*v, vec![
                 vec![TypedValue::Uuid(Uuid::from_str("cf62d552-6569-4d1b-b667-04703041dfc4").expect("Valid UUID")),]
-            ]);
+            ].into());
         },
         _ => panic!("Expected query to work."),
     }
@@ -451,7 +451,7 @@ fn test_fulltext() {
                 vec![TypedValue::Ref(v),
                      TypedValue::String("I've come to talk with you again".to_string().into()),
                 ]
-            ]);
+            ].into());
         },
         _ => panic!("Expected query to work."),
     }
@@ -693,17 +693,16 @@ fn test_type_reqs() {
     let eid_query = r#"[:find ?eid :where [?eid :test/string "foo"]]"#;
 
     let res = conn.q_once(&mut c, eid_query, None)
-                  .expect("results")
+                  .into_rel_result()
-                  .into();
+                  .expect("results");
 
-    let entid = match res {
+    assert_eq!(res.row_count(), 1);
-        QueryResults::Rel(ref vs) if vs.len() == 1 && vs[0].len() == 1 && vs[0][0].matches_type(ValueType::Ref) =>
+    assert_eq!(res.width, 1);
-            if let TypedValue::Ref(eid) = vs[0][0] {
+    let entid =
+        match res.into_iter().next().unwrap().into_iter().next().unwrap() {
+            TypedValue::Ref(eid) => {
                 eid
-            } else {
+            },
-                // Already checked this.
-                unreachable!();
-            }
             unexpected => {
                 panic!("Query to get the entity id returned unexpected result {:?}", unexpected);
             }
@@ -835,7 +834,7 @@ fn test_monster_head_aggregates() {
                 vec!["Cyclops".into(),  TypedValue::Long(3)],
                 vec!["Medusa".into(),   TypedValue::Long(1)],
             ];
-            assert_eq!(vals, expected);
+            assert_eq!(vals, expected.into());
         },
         r => panic!("Unexpected result {:?}", r),
     };
@@ -898,7 +897,7 @@ fn test_basic_aggregates() {
                  .into();
     match r {
         QueryResults::Rel(vals) => {
-            assert_eq!(vals, vec![vec![TypedValue::Long(1)]]);
+            assert_eq!(vals, vec![vec![TypedValue::Long(1)]].into());
         },
         _ => panic!("Expected rel."),
     }
@@ -994,7 +993,7 @@ fn test_basic_aggregates() {
                 vec![TypedValue::Long(22), TypedValue::Long(1)],
                 vec![TypedValue::Long(28), TypedValue::Long(1)],
                 vec![TypedValue::Long(42), TypedValue::Long(1)],
-            ]);
+            ].into());
         },
         _ => panic!("Expected rel."),
     }
@@ -1014,7 +1013,7 @@ fn test_basic_aggregates() {
                 vec![TypedValue::Long(22), TypedValue::Long(1)],
                 vec![TypedValue::Long(28), TypedValue::Long(2)],
                 vec![TypedValue::Long(42), TypedValue::Long(1)],
-            ]);
+            ].into());
         },
         _ => panic!("Expected rel."),
     }
@@ -1184,12 +1183,12 @@ fn test_aggregate_the() {
     // that corresponds to the maximum visit date.
     //
     // 'Group' in this context translates to GROUP BY in the generated SQL.
-    assert_eq!(2, per_title.len());
+    assert_eq!(2, per_title.row_count());
-    assert_eq!(1, corresponding_title.len());
+    assert_eq!(1, corresponding_title.row_count());
 
     assert_eq!(corresponding_title,
                vec![vec![TypedValue::Instant(DateTime::<Utc>::from_str("2018-04-06T20:46:00.000Z").unwrap()),
-                         TypedValue::typed_string("(1) Facebook")]]);
+                         TypedValue::typed_string("(1) Facebook")]].into());
 }
 
 #[test]
@@ -1293,8 +1292,10 @@ fn test_aggregation_implicit_grouping() {
     }
 
     // Max scores for vegetarians.
-    assert_eq!(vec![vec!["Alice".into(), TypedValue::Long(99)],
+    let expected: RelResult =
-                    vec!["Beli".into(), TypedValue::Long(22)]],
+        vec![vec!["Alice".into(), TypedValue::Long(99)],
+             vec!["Beli".into(), TypedValue::Long(22)]].into();
+    assert_eq!(expected,
                store.q_once(r#"[:find ?name (max ?score)
                                 :where
                                 [?game :foo/score ?score]
@@ -1336,7 +1337,7 @@ fn test_aggregation_implicit_grouping() {
                          TypedValue::String("Diana".to_string().into()),
                          TypedValue::Long(28),
                          TypedValue::Long(2),
-                         TypedValue::Double((33f64 / 2f64).into())]]);
+                         TypedValue::Double((33f64 / 2f64).into())]].into());
         },
         x => panic!("Got unexpected results {:?}", x),
     }
@@ -1444,7 +1445,7 @@ fn test_tx_data() {
                                     TypedValue::Instant(tx.tx_instant),
                                     TypedValue::Ref(tx.tx_id),
                                     TypedValue::Boolean(true)],
-                           ]);
+                           ].into());
             },
             x => panic!("Got unexpected results {:?}", x),
         }

tests/vocabulary.rs

@@ -47,6 +47,7 @@ use mentat::{
     NamespacedKeyword,
     QueryInputs,
     Queryable,
+    RelResult,
     Store,
     TypedValue,
     ValueType,
@@ -132,7 +133,7 @@ fn test_real_world() {
                       .into_rel_result()
                       .expect("query succeeded");
     assert_eq!(results,
-               vec![vec![alice, now.clone()], vec![barbara, now.clone()]]);
+               vec![vec![alice, now.clone()], vec![barbara, now.clone()]].into());
 }
 
 #[test]
@@ -1031,9 +1032,10 @@ fn test_upgrade_with_functions() {
                        [?p :person/height ?height]
                        [?p :person/name ?name]]"#;
     let r = store.q_once(q, None).into_rel_result().unwrap();
-    assert_eq!(vec![vec![TypedValue::typed_string("Sam"), TypedValue::Long(162)],
+    let expected: RelResult =
-                    vec![TypedValue::typed_string("Beth"), TypedValue::Long(172)]],
+        vec![vec![TypedValue::typed_string("Sam"), TypedValue::Long(162)],
-               r);
+             vec![TypedValue::typed_string("Beth"), TypedValue::Long(172)]].into();
+    assert_eq!(expected, r);
 
     // Find foods that Upstream Color fans like.
     let q = r#"[:find [?food ...]