Add :limit to queries (#420) r=nalexander

* Pre: put query parts in alphabetical order.
* Pre: rename 'input' to 'query' in translate tests.
* Part 1: parse :limit.
* Part 2: validate and escape variable parameters in SQL.
* Part 3: algebrize and translate limits.

query-algebrizer/src/clauses/mod.rs

@@ -441,6 +441,11 @@ impl ConjoiningClauses {
             QueryValue::PrimitiveLong(value)))
     }
 
+    /// Mark the given value as a long.
+    pub fn constrain_var_to_long(&mut self, variable: Variable) {
+        self.narrow_types_for_var(variable, unit_type_set(ValueType::Long));
+    }
+
     /// Mark the given value as one of the set of numeric types.
     fn constrain_var_to_numeric(&mut self, variable: Variable) {
         let mut numeric_types = HashSet::with_capacity(2);

query-algebrizer/src/errors.rs

@@ -47,6 +47,11 @@ error_chain! {
             display("invalid argument to {}: expected numeric in position {}.", function, position)
         }
 
+        InvalidLimit(val: String, kind: ValueType) {
+            description("invalid limit")
+            display("invalid limit {} of type {}: expected natural number.", val, kind)
+        }
+
         NonMatchingVariablesInOrClause {
             // TODO: flesh out.
             description("non-matching variables in 'or' clause")

query-algebrizer/src/lib.rs

@@ -24,6 +24,8 @@ mod clauses;
 
 use mentat_core::{
     Schema,
+    TypedValue,
+    ValueType,
 };
 
 use mentat_core::counter::RcCounter;
@@ -31,6 +33,7 @@ use mentat_core::counter::RcCounter;
 use mentat_query::{
     FindQuery,
     FindSpec,
+    Limit,
     Order,
     SrcVar,
     Variable,
@@ -53,28 +56,11 @@ pub struct AlgebraicQuery {
     has_aggregates: bool,
     pub with: BTreeSet<Variable>,
     pub order: Option<Vec<OrderBy>>,
-    pub limit: Option<u64>,
+    pub limit: Limit,
     pub cc: clauses::ConjoiningClauses,
 }
 
 impl AlgebraicQuery {
-    /**
-     * Apply a new limit to this query, if one is provided and any existing limit is larger.
-     */
-    pub fn apply_limit(&mut self, limit: Option<u64>) {
-        match self.limit {
-            None => self.limit = limit,
-            Some(existing) =>
-                match limit {
-                    None => (),
-                    Some(new) =>
-                        if new < existing {
-                            self.limit = limit;
-                        },
-                },
-        };
-    }
-
     #[inline]
     pub fn is_known_empty(&self) -> bool {
         self.cc.is_known_empty()
@@ -131,6 +117,45 @@ fn validate_and_simplify_order(cc: &ConjoiningClauses, order: Option<Vec<Order>>
     }
 }
 
+
+fn simplify_limit(mut query: AlgebraicQuery) -> Result<AlgebraicQuery> {
+    // Unpack any limit variables in place.
+    let refined_limit =
+        match query.limit {
+            Limit::Variable(ref v) => {
+                match query.cc.bound_value(v) {
+                    Some(TypedValue::Long(n)) => {
+                        if n <= 0 {
+                            // User-specified limits should always be natural numbers (> 0).
+                            bail!(ErrorKind::InvalidLimit(n.to_string(), ValueType::Long));
+                        } else {
+                            Some(Limit::Fixed(n as u64))
+                        }
+                    },
+                    Some(val) => {
+                        // Same.
+                        bail!(ErrorKind::InvalidLimit(format!("{:?}", val), val.value_type()));
+                    },
+                    None => {
+                        // We know that the limit variable is mentioned in `:in`.
+                        // That it's not bound here implies that we haven't got all the variables
+                        // we'll need to run the query yet.
+                        // (We should never hit this in `q_once`.)
+                        // Simply pass the `Limit` through to `SelectQuery` untouched.
+                        None
+                    },
+                }
+            },
+            Limit::None => None,
+            Limit::Fixed(_) => None,
+        };
+
+    if let Some(lim) = refined_limit {
+        query.limit = lim;
+    }
+    Ok(query)
+}
+
 pub fn algebrize_with_inputs(schema: &Schema,
                              parsed: FindQuery,
                              counter: usize,
@@ -138,6 +163,11 @@ pub fn algebrize_with_inputs(schema: &Schema,
     let alias_counter = RcCounter::with_initial(counter);
     let mut cc = ConjoiningClauses::with_inputs_and_alias_counter(parsed.in_vars, inputs, alias_counter);
 
+    // Do we have a variable limit? If so, tell the CC that the var must be numeric.
+    if let &Limit::Variable(ref var) = &parsed.limit {
+        cc.constrain_var_to_long(var.clone());
+    }
+
     // TODO: integrate default source into pattern processing.
     // TODO: flesh out the rest of find-into-context.
     let where_clauses = parsed.where_clauses;
@@ -149,8 +179,10 @@ pub fn algebrize_with_inputs(schema: &Schema,
 
     let (order, extra_vars) = validate_and_simplify_order(&cc, parsed.order)?;
     let with: BTreeSet<Variable> = parsed.with.into_iter().chain(extra_vars.into_iter()).collect();
-    let limit = if parsed.find_spec.is_unit_limited() { Some(1) } else { None };
+
-    Ok(AlgebraicQuery {
+    // This might leave us with an unused `:in` variable.
+    let limit = if parsed.find_spec.is_unit_limited() { Limit::Fixed(1) } else { parsed.limit };
+    let q = AlgebraicQuery {
         default_source: parsed.default_source,
         find_spec: parsed.find_spec,
         has_aggregates: false,           // TODO: we don't parse them yet.
@@ -158,7 +190,10 @@ pub fn algebrize_with_inputs(schema: &Schema,
         order: order,
         limit: limit,
         cc: cc,
-    })
+    };
+
+    // Substitute in any fixed values and fail if they're out of range.
+    simplify_limit(q)
 }
 
 pub use clauses::{

query-parser/src/parse.rs

@@ -18,7 +18,7 @@ use std; // To refer to std::result::Result.
 use std::collections::BTreeSet;
 
 use self::combine::{eof, many, many1, optional, parser, satisfy, satisfy_map, Parser, ParseResult, Stream};
-use self::combine::combinator::{choice, or, try};
+use self::combine::combinator::{any, choice, or, try};
 
 use self::mentat_parser_utils::{
     ResultParser,
@@ -43,6 +43,7 @@ use self::mentat_query::{
     FindSpec,
     FnArg,
     FromValue,
+    Limit,
     Order,
     OrJoin,
     OrWhereClause,
@@ -102,6 +103,16 @@ error_chain! {
             description("missing field")
             display("missing field: '{}'", value)
         }
+
+        UnknownLimitVar(var: edn::PlainSymbol) {
+            description("limit var not present in :in")
+            display("limit var {} not present in :in", var)
+        }
+
+        InvalidLimit(val: edn::Value) {
+            description("limit value not valid")
+            display("expected natural number, got {}", val)
+        }
     }
 }
 
@@ -156,6 +167,20 @@ def_parser!(Where, pattern_value_place, PatternValuePlace,  {
     satisfy_map(PatternValuePlace::from_value)
 });
 
+def_parser!(Query, natural_number, u64, {
+    any().and_then(|v: edn::ValueAndSpan| {
+        match v.inner {
+            edn::SpannedValue::Integer(x) if (x > 0) => {
+                Ok(x as u64)
+            },
+            spanned => {
+                let e = Box::new(Error::from_kind(ErrorKind::InvalidLimit(spanned.into())));
+                Err(combine::primitives::Error::Other(e))
+            },
+        }
+    })
+});
+
 def_parser!(Where, pattern_non_value_place, PatternNonValuePlace, {
     satisfy_map(PatternNonValuePlace::from_value)
 });
@@ -334,22 +359,20 @@ def_parser!(Find, spec, FindSpec, {
 });
 
 def_matches_keyword!(Find, literal_find, "find");
-
 def_matches_keyword!(Find, literal_in, "in");
-
+def_matches_keyword!(Find, literal_limit, "limit");
-def_matches_keyword!(Find, literal_with, "with");
-
-def_matches_keyword!(Find, literal_where, "where");
-
 def_matches_keyword!(Find, literal_order, "order");
+def_matches_keyword!(Find, literal_where, "where");
+def_matches_keyword!(Find, literal_with, "with");
 
 /// Express something close to a builder pattern for a `FindQuery`.
 enum FindQueryPart {
     FindSpec(FindSpec),
-    With(BTreeSet<Variable>),
     In(BTreeSet<Variable>),
-    WhereClauses(Vec<WhereClause>),
+    Limit(Limit),
     Order(Vec<Order>),
+    WhereClauses(Vec<WhereClause>),
+    With(BTreeSet<Variable>),
 }
 
 def_parser!(Find, vars, BTreeSet<Variable>, {
@@ -373,49 +396,72 @@ def_parser!(Find, query, FindQuery, {
     let p_find_spec = Find::literal_find()
         .with(vector().of_exactly(Find::spec().map(FindQueryPart::FindSpec)));
 
-    let p_in_vars = Find::literal_in().with(Find::vars().map(FindQueryPart::In));
+    let p_in_vars = Find::literal_in()
+        .with(Find::vars().map(FindQueryPart::In));
 
-    let p_with_vars = Find::literal_with().with(Find::vars().map(FindQueryPart::With));
+    let p_limit = Find::literal_limit()
-
+        .with(vector().of_exactly(
-    let p_where_clauses = Find::literal_where()
+            Query::variable().map(|v| Limit::Variable(v))
-        .with(vector().of_exactly(Where::clauses().map(FindQueryPart::WhereClauses))).expected(":where clauses");
+                             .or(Query::natural_number().map(|n| Limit::Fixed(n)))))
+        .map(FindQueryPart::Limit);
 
     let p_order_clauses = Find::literal_order()
         .with(vector().of_exactly(many1(Query::order()).map(FindQueryPart::Order)));
 
+    let p_where_clauses = Find::literal_where()
+        .with(vector().of_exactly(Where::clauses().map(FindQueryPart::WhereClauses)))
+        .expected(":where clauses");
+
+    let p_with_vars = Find::literal_with()
+        .with(Find::vars().map(FindQueryPart::With));
+
     (or(map(), keyword_map()))
-        .of_exactly(many(choice::<[&mut Parser<Input = ValueStream, Output = FindQueryPart>; 5], _>([
+        .of_exactly(many(choice::<[&mut Parser<Input = ValueStream, Output = FindQueryPart>; 6], _>([
+            // Ordered by likelihood.
             &mut try(p_find_spec),
-            &mut try(p_in_vars),
-            &mut try(p_with_vars),
             &mut try(p_where_clauses),
+            &mut try(p_in_vars),
+            &mut try(p_limit),
             &mut try(p_order_clauses),
+            &mut try(p_with_vars),
         ])))
         .and_then(|parts: Vec<FindQueryPart>| -> std::result::Result<FindQuery, combine::primitives::Error<edn::ValueAndSpan, edn::ValueAndSpan>>  {
             let mut find_spec = None;
             let mut in_vars = None;
-            let mut with_vars = None;
+            let mut limit = Limit::None;
-            let mut where_clauses = None;
             let mut order_clauses = None;
+            let mut where_clauses = None;
+            let mut with_vars = None;
 
             for part in parts {
                 match part {
                     FindQueryPart::FindSpec(x) => find_spec = Some(x),
-                    FindQueryPart::With(x) => with_vars = Some(x),
                     FindQueryPart::In(x) => in_vars = Some(x),
-                    FindQueryPart::WhereClauses(x) => where_clauses = Some(x),
+                    FindQueryPart::Limit(x) => limit = x,
                     FindQueryPart::Order(x) => order_clauses = Some(x),
+                    FindQueryPart::WhereClauses(x) => where_clauses = Some(x),
+                    FindQueryPart::With(x) => with_vars = Some(x),
+                }
+            }
+
+            // Make sure that if we have `:limit ?x`, `?x` appears in `:in`.
+            let in_vars = in_vars.unwrap_or(BTreeSet::default());
+            if let Limit::Variable(ref v) = limit {
+                if !in_vars.contains(v) {
+                    let e = Box::new(Error::from_kind(ErrorKind::UnknownLimitVar(v.name())));
+                    return Err(combine::primitives::Error::Other(e));
                 }
             }
 
             Ok(FindQuery {
-                find_spec: find_spec.clone().ok_or(combine::primitives::Error::Unexpected("expected :find".into()))?,
                 default_source: SrcVar::DefaultSrc,
-                with: with_vars.unwrap_or(BTreeSet::default()),
+                find_spec: find_spec.clone().ok_or(combine::primitives::Error::Unexpected("expected :find".into()))?,
-                in_vars: in_vars.unwrap_or(BTreeSet::default()),
                 in_sources: BTreeSet::default(),    // TODO
+                in_vars: in_vars,
+                limit: limit,
                 order: order_clauses,
                 where_clauses: where_clauses.ok_or(combine::primitives::Error::Unexpected("expected :where".into()))?,
+                with: with_vars.unwrap_or(BTreeSet::default()),
             })
         })
 });
@@ -675,4 +721,31 @@ mod test {
                           FindSpec::FindTuple(vec![Element::Variable(variable(vx)),
                                                    Element::Variable(variable(vy))]));
     }
+
+    #[test]
+    fn test_natural_numbers() {
+        let text = edn::Value::Text("foo".to_string());
+        let neg = edn::Value::Integer(-10);
+        let zero = edn::Value::Integer(0);
+        let pos = edn::Value::Integer(5);
+
+        // This is terrible, but destructuring errors is a shitshow.
+        let mut par = Query::natural_number();
+        let x = par.parse(text.with_spans().into_atom_stream()).err().expect("an error").errors;
+        let result = format!("{:?}", x);
+        assert_eq!(result, "[Other(Error(InvalidLimit(Text(\"foo\")), State { next_error: None, backtrace: None })), Expected(Borrowed(\"natural_number\"))]");
+
+        let mut par = Query::natural_number();
+        let x = par.parse(neg.with_spans().into_atom_stream()).err().expect("an error").errors;
+        let result = format!("{:?}", x);
+        assert_eq!(result, "[Other(Error(InvalidLimit(Integer(-10)), State { next_error: None, backtrace: None })), Expected(Borrowed(\"natural_number\"))]");
+
+        let mut par = Query::natural_number();
+        let x = par.parse(zero.with_spans().into_atom_stream()).err().expect("an error").errors;
+        let result = format!("{:?}", x);
+        assert_eq!(result, "[Other(Error(InvalidLimit(Integer(0)), State { next_error: None, backtrace: None })), Expected(Borrowed(\"natural_number\"))]");
+
+        let mut par = Query::natural_number();
+        assert_eq!(None, par.parse(pos.with_spans().into_atom_stream()).err());
+    }
 }

query-parser/tests/find_tests.rs

@@ -8,9 +8,9 @@
 // CONDITIONS OF ANY KIND, either express or implied. See the License for the
 // specific language governing permissions and limitations under the License.
 
-extern crate mentat_query_parser;
-extern crate mentat_query;
 extern crate edn;
+extern crate mentat_query;
+extern crate mentat_query_parser;
 
 use edn::{
     NamespacedKeyword,
@@ -22,6 +22,7 @@ use mentat_query::{
     Element,
     FindSpec,
     FnArg,
+    Limit,
     Order,
     OrJoin,
     OrWhereClause,
@@ -123,7 +124,7 @@ fn can_parse_unit_or_join() {
 
 #[test]
 fn can_parse_simple_or_join() {
-    let s = "[:find ?x . :where (or-join [?x] [?x _ 10] [?x _ 15])]";
+    let s = "[:find ?x . :where (or-join [?x] [?x _ 10] [?x _ -15])]";
     let p = parse_find_string(s).unwrap();
 
     assert_eq!(p.find_spec,
@@ -146,7 +147,7 @@ fn can_parse_simple_or_join() {
                                    source: None,
                                    entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
                                    attribute: PatternNonValuePlace::Placeholder,
-                                   value: PatternValuePlace::EntidOrInteger(15),
+                                   value: PatternValuePlace::EntidOrInteger(-15),
                                    tx: PatternNonValuePlace::Placeholder,
                                })),
                        ],
@@ -234,3 +235,35 @@ fn can_parse_order_by() {
                Some(vec![Order(Direction::Descending, Variable::from_valid_name("?y")),
                          Order(Direction::Ascending, Variable::from_valid_name("?x"))]));
 }
+
+#[test]
+fn can_parse_limit() {
+    let invalid = "[:find ?x :where [?x :foo/baz ?y] :limit]";
+    assert!(parse_find_string(invalid).is_err());
+
+    let zero_invalid = "[:find ?x :where [?x :foo/baz ?y] :limit 00]";
+    assert!(parse_find_string(zero_invalid).is_err());
+
+    let none = "[:find ?x :where [?x :foo/baz ?y]]";
+    assert_eq!(parse_find_string(none).unwrap().limit,
+               Limit::None);
+
+    let one = "[:find ?x :where [?x :foo/baz ?y] :limit 1]";
+    assert_eq!(parse_find_string(one).unwrap().limit,
+               Limit::Fixed(1));
+
+    let onethousand = "[:find ?x :where [?x :foo/baz ?y] :limit 1000]";
+    assert_eq!(parse_find_string(onethousand).unwrap().limit,
+               Limit::Fixed(1000));
+
+    let variable_with_in = "[:find ?x :in ?limit :where [?x :foo/baz ?y] :limit ?limit]";
+    assert_eq!(parse_find_string(variable_with_in).unwrap().limit,
+               Limit::Variable(Variable::from_valid_name("?limit")));
+
+    let variable_with_in_used = "[:find ?x :in ?limit :where [?x :foo/baz ?limit] :limit ?limit]";
+    assert_eq!(parse_find_string(variable_with_in_used).unwrap().limit,
+               Limit::Variable(Variable::from_valid_name("?limit")));
+
+    let variable_without_in = "[:find ?x :where [?x :foo/baz ?y] :limit ?limit]";
+    assert!(parse_find_string(variable_without_in).is_err());
+}

query-projector/src/lib.rs

@@ -37,6 +37,7 @@ use mentat_db::{
 use mentat_query::{
     Element,
     FindSpec,
+    Limit,
     Variable,
 };
 
@@ -442,8 +443,8 @@ pub struct CombinedProjection {
 }
 
 impl CombinedProjection {
-    fn flip_distinct_for_limit(mut self, limit: Option<u64>) -> Self {
+    fn flip_distinct_for_limit(mut self, limit: &Limit) -> Self {
-        if limit == Some(1) {
+        if *limit == Limit::Fixed(1) {
             self.distinct = false;
         }
         self
@@ -474,7 +475,7 @@ pub fn query_projection(query: &AlgebraicQuery) -> CombinedProjection {
         match query.find_spec {
             FindColl(ref element) => {
                 let (cols, templates) = project_elements(1, iter::once(element), query);
-                CollProjector::combine(cols, templates).flip_distinct_for_limit(query.limit)
+                CollProjector::combine(cols, templates).flip_distinct_for_limit(&query.limit)
             },
 
             FindScalar(ref element) => {
@@ -485,7 +486,7 @@ pub fn query_projection(query: &AlgebraicQuery) -> CombinedProjection {
             FindRel(ref elements) => {
                 let column_count = query.find_spec.expected_column_count();
                 let (cols, templates) = project_elements(column_count, elements, query);
-                RelProjector::combine(column_count, cols, templates).flip_distinct_for_limit(query.limit)
+                RelProjector::combine(column_count, cols, templates).flip_distinct_for_limit(&query.limit)
             },
 
             FindTuple(ref elements) => {

query-sql/Cargo.toml

@@ -4,6 +4,8 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
+regex = "0.2"
+
 [dependencies.mentat_core]
 path = "../core"
 

query-sql/src/lib.rs

@@ -8,6 +8,7 @@
 // CONDITIONS OF ANY KIND, either express or implied. See the License for the
 // specific language governing permissions and limitations under the License.
 
+extern crate regex;
 extern crate mentat_core;
 extern crate mentat_query;
 extern crate mentat_query_algebrizer;
@@ -20,6 +21,8 @@ use mentat_core::{
 
 use mentat_query::{
     Direction,
+    Limit,
+    Variable,
 };
 
 use mentat_query_algebrizer::{
@@ -158,7 +161,7 @@ pub struct SelectQuery {
     pub from: FromClause,
     pub constraints: Vec<Constraint>,
     pub order: Vec<OrderBy>,
-    pub limit: Option<u64>,
+    pub limit: Limit,
 }
 
 fn push_variable_column(qb: &mut QueryBuilder, vc: &VariableColumn) -> BuildQueryResult {
@@ -401,6 +404,19 @@ impl QueryFragment for FromClause {
     }
 }
 
+impl SelectQuery {
+    fn push_variable_param(&self, var: &Variable, out: &mut QueryBuilder) -> BuildQueryResult {
+        // `var` is something like `?foo99-people`.
+        // Trim the `?` and escape the rest. Prepend `i` to distinguish from
+        // the inline value space `v`.
+        let re = regex::Regex::new("[^a-zA-Z_0-9]").unwrap();
+        let without_question = var.as_str().split_at(1).1;
+        let replaced = re.replace_all(without_question, "_");
+        let bind_param = format!("i{}", replaced);                 // We _could_ avoid this copying.
+        out.push_bind_param(bind_param.as_str())
+    }
+}
+
 impl QueryFragment for SelectQuery {
     fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult {
         if self.distinct {
@@ -430,10 +446,18 @@ impl QueryFragment for SelectQuery {
                        { out.push_sql(", ") });
         }
 
-        // Guaranteed to be positive: u64.
+        match &self.limit {
-        if let Some(limit) = self.limit {
+            &Limit::None => (),
-            out.push_sql(" LIMIT ");
+            &Limit::Fixed(limit) => {
-            out.push_sql(limit.to_string().as_str());
+                // Guaranteed to be non-negative: u64.
+                out.push_sql(" LIMIT ");
+                out.push_sql(limit.to_string().as_str());
+            },
+            &Limit::Variable(ref var) => {
+                // Guess this wasn't bound yet. Produce an argument.
+                out.push_sql(" LIMIT ");
+                self.push_variable_param(var, out)?;
+            },
         }
 
         Ok(())
@@ -554,7 +578,7 @@ mod tests {
                 },
             ],
             order: vec![],
-            limit: None,
+            limit: Limit::None,
         };
 
         let SQLQuery { sql, args } = query.to_sql_query().unwrap();

query-translator/src/translate.rs

@@ -14,6 +14,8 @@ use mentat_core::{
     ValueType,
 };
 
+use mentat_query::Limit;
+
 use mentat_query_algebrizer::{
     AlgebraicQuery,
     ColumnAlternation,
@@ -224,7 +226,7 @@ fn table_for_computed(computed: ComputedTable, alias: TableAlias) -> TableOrSubq
                         // Each arm simply turns into a subquery.
                         // The SQL translation will stuff "UNION" between each arm.
                         let projection = Projection::Columns(columns);
-                        cc_to_select_query(projection, cc, false, None, None)
+                        cc_to_select_query(projection, cc, false, None, Limit::None)
                   }).collect(),
                 alias)
         },
@@ -234,11 +236,11 @@ fn table_for_computed(computed: ComputedTable, alias: TableAlias) -> TableOrSubq
 /// Returns a `SelectQuery` that queries for the provided `cc`. Note that this _always_ returns a
 /// query that runs SQL. The next level up the call stack can check for known-empty queries if
 /// needed.
-fn cc_to_select_query<T>(projection: Projection,
+fn cc_to_select_query(projection: Projection,
-                         cc: ConjoiningClauses,
+                      cc: ConjoiningClauses,
-                         distinct: bool,
+                      distinct: bool,
-                         order: Option<Vec<OrderBy>>,
+                      order: Option<Vec<OrderBy>>,
-                         limit: T) -> SelectQuery where T: Into<Option<u64>> {
+                      limit: Limit) -> SelectQuery {
     let from = if cc.from.is_empty() {
         FromClause::Nothing
     } else {
@@ -268,7 +270,7 @@ fn cc_to_select_query<T>(projection: Projection,
 
     // Turn the query-centric order clauses into column-orders.
     let order = order.map_or(vec![], |vec| { vec.into_iter().map(|o| o.into()).collect() });
-    let limit = if cc.empty_because.is_some() { Some(0) } else { limit.into() };
+    let limit = if cc.empty_because.is_some() { Limit::Fixed(0) } else { limit };
     SelectQuery {
         distinct: distinct,
         projection: projection,
@@ -293,10 +295,10 @@ pub fn cc_to_exists(cc: ConjoiningClauses) -> SelectQuery {
             from: FromClause::Nothing,
             constraints: vec![],
             order: vec![],
-            limit: Some(0),
+            limit: Limit::Fixed(0),
         }
     } else {
-        cc_to_select_query(Projection::One, cc, false, None, 1)
+        cc_to_select_query(Projection::One, cc, false, None, Limit::Fixed(1))
     }
 }
 

query-translator/tests/translate.rs

@@ -17,17 +17,25 @@ extern crate mentat_sql;
 
 use std::rc::Rc;
 
-use mentat_query::NamespacedKeyword;
+use mentat_query::{
+    NamespacedKeyword,
+    Variable,
+};
 
 use mentat_core::{
     Attribute,
     Entid,
     Schema,
+    TypedValue,
     ValueType,
 };
 
 use mentat_query_parser::parse_find_string;
-use mentat_query_algebrizer::algebrize;
+use mentat_query_algebrizer::{
+    QueryInputs,
+    algebrize,
+    algebrize_with_inputs,
+};
 use mentat_query_translator::{
     query_to_select,
 };
@@ -43,14 +51,17 @@ fn add_attribute(schema: &mut Schema, e: Entid, a: Attribute) {
     schema.schema_map.insert(e, a);
 }
 
-fn translate<T: Into<Option<u64>>>(schema: &Schema, input: &'static str, limit: T) -> SQLQuery {
+fn translate_with_inputs(schema: &Schema, query: &'static str, inputs: QueryInputs) -> SQLQuery {
-    let parsed = parse_find_string(input).expect("parse failed");
+    let parsed = parse_find_string(query).expect("parse failed");
-    let mut algebrized = algebrize(schema, parsed).expect("algebrize failed");
+    let algebrized = algebrize_with_inputs(schema, parsed, 0, inputs).expect("algebrize failed");
-    algebrized.apply_limit(limit.into());
     let select = query_to_select(algebrized);
     select.query.to_sql_query().unwrap()
 }
 
+fn translate(schema: &Schema, query: &'static str) -> SQLQuery {
+    translate_with_inputs(schema, query, QueryInputs::default())
+}
+
 fn prepopulated_typed_schema(foo_type: ValueType) -> Schema {
     let mut schema = Schema::default();
     associate_ident(&mut schema, NamespacedKeyword::new("foo", "bar"), 99);
@@ -73,8 +84,8 @@ fn make_arg(name: &'static str, value: &'static str) -> (String, Rc<String>) {
 fn test_scalar() {
     let schema = prepopulated_schema();
 
-    let input = r#"[:find ?x . :where [?x :foo/bar "yyy"]]"#;
+    let query = r#"[:find ?x . :where [?x :foo/bar "yyy"]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 LIMIT 1");
     assert_eq!(args, vec![make_arg("$v0", "yyy")]);
 }
@@ -83,8 +94,8 @@ fn test_scalar() {
 fn test_tuple() {
     let schema = prepopulated_schema();
 
-    let input = r#"[:find [?x] :where [?x :foo/bar "yyy"]]"#;
+    let query = r#"[:find [?x] :where [?x :foo/bar "yyy"]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 LIMIT 1");
     assert_eq!(args, vec![make_arg("$v0", "yyy")]);
 }
@@ -93,8 +104,8 @@ fn test_tuple() {
 fn test_coll() {
     let schema = prepopulated_schema();
 
-    let input = r#"[:find [?x ...] :where [?x :foo/bar "yyy"]]"#;
+    let query = r#"[:find [?x ...] :where [?x :foo/bar "yyy"]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0");
     assert_eq!(args, vec![make_arg("$v0", "yyy")]);
 }
@@ -103,8 +114,8 @@ fn test_coll() {
 fn test_rel() {
     let schema = prepopulated_schema();
 
-    let input = r#"[:find ?x :where [?x :foo/bar "yyy"]]"#;
+    let query = r#"[:find ?x :where [?x :foo/bar "yyy"]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0");
     assert_eq!(args, vec![make_arg("$v0", "yyy")]);
 }
@@ -113,18 +124,80 @@ fn test_rel() {
 fn test_limit() {
     let schema = prepopulated_schema();
 
-    let input = r#"[:find ?x :where [?x :foo/bar "yyy"]]"#;
+    let query = r#"[:find ?x :where [?x :foo/bar "yyy"] :limit 5]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, 5);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 LIMIT 5");
     assert_eq!(args, vec![make_arg("$v0", "yyy")]);
 }
 
+#[test]
+fn test_unbound_variable_limit() {
+    let schema = prepopulated_schema();
+
+    // We don't know the value of the limit var, so we produce an escaped SQL variable to handle
+    // later input.
+    let query = r#"[:find ?x :in ?limit-is-9-great :where [?x :foo/bar "yyy"] :limit ?limit-is-9-great]"#;
+    let SQLQuery { sql, args } = translate_with_inputs(&schema, query, QueryInputs::default());
+    assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` \
+                     FROM `datoms` AS `datoms00` \
+                     WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 \
+                     LIMIT $ilimit_is_9_great");
+    assert_eq!(args, vec![make_arg("$v0", "yyy")]);
+}
+
+#[test]
+fn test_bound_variable_limit() {
+    let schema = prepopulated_schema();
+
+    // We know the value of `?limit` at algebrizing time, so we substitute directly.
+    let query = r#"[:find ?x :in ?limit :where [?x :foo/bar "yyy"] :limit ?limit]"#;
+    let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?limit"), TypedValue::Long(92))]);
+    let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
+    assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 LIMIT 92");
+    assert_eq!(args, vec![make_arg("$v0", "yyy")]);
+}
+
+#[test]
+fn test_bound_variable_limit_affects_distinct() {
+    let schema = prepopulated_schema();
+
+    // We know the value of `?limit` at algebrizing time, so we substitute directly.
+    // As it's `1`, we know we don't need `DISTINCT`!
+    let query = r#"[:find ?x :in ?limit :where [?x :foo/bar "yyy"] :limit ?limit]"#;
+    let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?limit"), TypedValue::Long(1))]);
+    let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
+    assert_eq!(sql, "SELECT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 LIMIT 1");
+    assert_eq!(args, vec![make_arg("$v0", "yyy")]);
+}
+
+#[test]
+fn test_bound_variable_limit_affects_types() {
+    let schema = prepopulated_schema();
+
+    let query = r#"[:find ?x ?limit :in ?limit :where [?x _ ?limit] :limit ?limit]"#;
+    let parsed = parse_find_string(query).expect("parse failed");
+    let algebrized = algebrize(&schema, parsed).expect("algebrize failed");
+
+    // The type is known.
+    assert_eq!(Some(ValueType::Long),
+               algebrized.cc.known_type(&Variable::from_valid_name("?limit")));
+
+    let select = query_to_select(algebrized);
+    let SQLQuery { sql, args } = select.query.to_sql_query().unwrap();
+
+    // TODO: this query isn't actually correct -- we don't yet algebrize for variables that are
+    // specified in `:in` but not provided at algebrizing time. But it shows what we care about
+    // at the moment: we don't project a type column, because we know it's a Long.
+    assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x`, `datoms00`.v AS `?limit` FROM `datoms` AS `datoms00` LIMIT $ilimit");
+    assert_eq!(args, vec![]);
+}
+
 #[test]
 fn test_unknown_attribute_keyword_value() {
     let schema = Schema::default();
 
-    let input = r#"[:find ?x :where [?x _ :ab/yyy]]"#;
+    let query = r#"[:find ?x :where [?x _ :ab/yyy]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
 
     // Only match keywords, not strings: tag = 13.
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.v = $v0 AND `datoms00`.value_type_tag = 13");
@@ -135,8 +208,8 @@ fn test_unknown_attribute_keyword_value() {
 fn test_unknown_attribute_string_value() {
     let schema = Schema::default();
 
-    let input = r#"[:find ?x :where [?x _ "horses"]]"#;
+    let query = r#"[:find ?x :where [?x _ "horses"]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
 
     // We expect all_datoms because we're querying for a string. Magic, that.
     // We don't want keywords etc., so tag = 10.
@@ -148,8 +221,8 @@ fn test_unknown_attribute_string_value() {
 fn test_unknown_attribute_double_value() {
     let schema = Schema::default();
 
-    let input = r#"[:find ?x :where [?x _ 9.95]]"#;
+    let query = r#"[:find ?x :where [?x _ 9.95]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
 
     // In general, doubles _could_ be 1.0, which might match a boolean or a ref. Set tag = 5 to
     // make sure we only match numbers.
@@ -167,22 +240,22 @@ fn test_unknown_attribute_integer_value() {
     let two = r#"[:find ?x :where [?x _ 2]]"#;
 
     // Can't match boolean; no need to filter it out.
-    let SQLQuery { sql, args } = translate(&schema, negative, None);
+    let SQLQuery { sql, args } = translate(&schema, negative);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.v = -1");
     assert_eq!(args, vec![]);
 
     // Excludes booleans.
-    let SQLQuery { sql, args } = translate(&schema, zero, None);
+    let SQLQuery { sql, args } = translate(&schema, zero);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE (`datoms00`.v = 0 AND `datoms00`.value_type_tag <> 1)");
     assert_eq!(args, vec![]);
 
     // Excludes booleans.
-    let SQLQuery { sql, args } = translate(&schema, one, None);
+    let SQLQuery { sql, args } = translate(&schema, one);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE (`datoms00`.v = 1 AND `datoms00`.value_type_tag <> 1)");
     assert_eq!(args, vec![]);
 
     // Can't match boolean; no need to filter it out.
-    let SQLQuery { sql, args } = translate(&schema, two, None);
+    let SQLQuery { sql, args } = translate(&schema, two);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.v = 2");
     assert_eq!(args, vec![]);
 }
@@ -208,8 +281,8 @@ fn test_unknown_ident() {
 fn test_numeric_less_than_unknown_attribute() {
     let schema = Schema::default();
 
-    let input = r#"[:find ?x :where [?x _ ?y] [(< ?y 10)]]"#;
+    let query = r#"[:find ?x :where [?x _ ?y] [(< ?y 10)]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
 
     // Although we infer numericness from numeric predicates, we've already assigned a table to the
     // first pattern, and so this is _still_ `all_datoms`.
@@ -220,8 +293,8 @@ fn test_numeric_less_than_unknown_attribute() {
 #[test]
 fn test_numeric_gte_known_attribute() {
     let schema = prepopulated_typed_schema(ValueType::Double);
-    let input = r#"[:find ?x :where [?x :foo/bar ?y] [(>= ?y 12.9)]]"#;
+    let query = r#"[:find ?x :where [?x :foo/bar ?y] [(>= ?y 12.9)]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v >= 12.9");
     assert_eq!(args, vec![]);
 }
@@ -229,8 +302,8 @@ fn test_numeric_gte_known_attribute() {
 #[test]
 fn test_numeric_not_equals_known_attribute() {
     let schema = prepopulated_typed_schema(ValueType::Long);
-    let input = r#"[:find ?x . :where [?x :foo/bar ?y] [(!= ?y 12)]]"#;
+    let query = r#"[:find ?x . :where [?x :foo/bar ?y] [(!= ?y 12)]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99 AND `datoms00`.v <> 12 LIMIT 1");
     assert_eq!(args, vec![]);
 }
@@ -248,14 +321,14 @@ fn test_simple_or_join() {
         });
     }
 
-    let input = r#"[:find [?url ?description]
+    let query = r#"[:find [?url ?description]
                     :where
                     (or-join [?page]
                       [?page :page/url "http://foo.com/"]
                       [?page :page/title "Foo"])
                     [?page :page/url ?url]
                     [?page :page/description ?description]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT `datoms01`.v AS `?url`, `datoms02`.v AS `?description` FROM `datoms` AS `datoms00`, `datoms` AS `datoms01`, `datoms` AS `datoms02` WHERE ((`datoms00`.a = 97 AND `datoms00`.v = $v0) OR (`datoms00`.a = 98 AND `datoms00`.v = $v1)) AND `datoms01`.a = 97 AND `datoms02`.a = 99 AND `datoms00`.e = `datoms01`.e AND `datoms00`.e = `datoms02`.e LIMIT 1");
     assert_eq!(args, vec![make_arg("$v0", "http://foo.com/"), make_arg("$v1", "Foo")]);
 }
@@ -280,7 +353,7 @@ fn test_complex_or_join() {
         });
     }
 
-    let input = r#"[:find [?url ?description]
+    let query = r#"[:find [?url ?description]
                     :where
                     (or-join [?page]
                       [?page :page/url "http://foo.com/"]
@@ -290,7 +363,7 @@ fn test_complex_or_join() {
                         [?save :save/title "Foo"]))
                     [?page :page/url ?url]
                     [?page :page/description ?description]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT `datoms04`.v AS `?url`, \
                             `datoms05`.v AS `?description` \
                      FROM (SELECT `datoms00`.e AS `?page` \
@@ -332,12 +405,12 @@ fn test_complex_or_join_type_projection() {
         ..Default::default()
     });
 
-    let input = r#"[:find [?y]
+    let query = r#"[:find [?y]
                     :where
                     (or
                       [6 :page/title ?y]
                       [5 _ ?y])]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT `c00`.`?y` AS `?y`, \
                             `c00`.`?y_value_type_tag` AS `?y_value_type_tag` \
                        FROM (SELECT `datoms00`.v AS `?y`, \
@@ -359,14 +432,14 @@ fn test_with_without_aggregate() {
     let schema = prepopulated_schema();
 
     // Known type.
-    let input = r#"[:find ?x :with ?y :where [?x :foo/bar ?y]]"#;
+    let query = r#"[:find ?x :with ?y :where [?x :foo/bar ?y]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x`, `datoms00`.v AS `?y` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 99");
     assert_eq!(args, vec![]);
 
     // Unknown type.
-    let input = r#"[:find ?x :with ?y :where [?x _ ?y]]"#;
+    let query = r#"[:find ?x :with ?y :where [?x _ ?y]]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT DISTINCT `all_datoms00`.e AS `?x`, `all_datoms00`.v AS `?y`, `all_datoms00`.value_type_tag AS `?y_value_type_tag` FROM `all_datoms` AS `all_datoms00`");
     assert_eq!(args, vec![]);
 }
@@ -376,8 +449,8 @@ fn test_order_by() {
     let schema = prepopulated_schema();
 
     // Known type.
-    let input = r#"[:find ?x :where [?x :foo/bar ?y] :order (desc ?y)]"#;
+    let query = r#"[:find ?x :where [?x :foo/bar ?y] :order (desc ?y)]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?x`, `datoms00`.v AS `?y` \
                      FROM `datoms` AS `datoms00` \
                      WHERE `datoms00`.a = 99 \
@@ -385,11 +458,11 @@ fn test_order_by() {
     assert_eq!(args, vec![]);
 
     // Unknown type.
-    let input = r#"[:find ?x :with ?y :where [?x _ ?y] :order ?y ?x]"#;
+    let query = r#"[:find ?x :with ?y :where [?x _ ?y] :order ?y ?x]"#;
-    let SQLQuery { sql, args } = translate(&schema, input, None);
+    let SQLQuery { sql, args } = translate(&schema, query);
     assert_eq!(sql, "SELECT DISTINCT `all_datoms00`.e AS `?x`, `all_datoms00`.v AS `?y`, \
                                      `all_datoms00`.value_type_tag AS `?y_value_type_tag` \
                      FROM `all_datoms` AS `all_datoms00` \
                      ORDER BY `?y_value_type_tag` ASC, `?y` ASC, `?x` ASC");
     assert_eq!(args, vec![]);
-}
+}

query/src/lib.rs

@@ -370,13 +370,20 @@ pub struct Aggregate {
 }
 */
 
-#[derive(Clone,Debug,Eq,PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub enum Element {
     Variable(Variable),
     // Aggregate(Aggregate),   // TODO
     // Pull(Pull),             // TODO
 }
 
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum Limit {
+    None,
+    Fixed(u64),
+    Variable(Variable),
+}
+
 /// A definition of the first part of a find query: the
 /// `[:find ?foo ?bar…]` bit.
 ///
@@ -408,7 +415,7 @@ pub enum Element {
 /// # }
 /// ```
 ///
-#[derive(Clone,Debug,Eq,PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub enum FindSpec {
     /// Returns an array of arrays.
     FindRel(Vec<Element>),
@@ -610,6 +617,7 @@ pub struct FindQuery {
     pub with: BTreeSet<Variable>,
     pub in_vars: BTreeSet<Variable>,
     pub in_sources: BTreeSet<SrcVar>,
+    pub limit: Limit,
     pub where_clauses: Vec<WhereClause>,
     pub order: Option<Vec<Order>>,
     // TODO: in_rules;

sql/src/lib.rs

@@ -154,7 +154,7 @@ impl QueryBuilder for SQLiteQueryBuilder {
     fn push_bind_param(&mut self, name: &str) -> BuildQueryResult {
         // Do some validation first.
         // This is not free, but it's probably worth it for now.
-        if !name.chars().all(char::is_alphanumeric) {
+        if !name.chars().all(|c| char::is_alphanumeric(c) || c == '_') {
             bail!(ErrorKind::InvalidParameterName(name.to_string()));
         }
 

src/conn.rs

@@ -110,20 +110,17 @@ impl Conn {
     }
 
     /// Query the Mentat store, using the given connection and the current metadata.
-    pub fn q_once<T, U>(&self,
+    pub fn q_once<T>(&self,
                      sqlite: &rusqlite::Connection,
                      query: &str,
-                     inputs: T,
+                     inputs: T) -> Result<QueryResults>
-                     limit: U) -> Result<QueryResults>
+        where T: Into<Option<QueryInputs>>
-        where T: Into<Option<QueryInputs>>,
-              U: Into<Option<u64>>
         {
 
         q_once(sqlite,
                &*self.current_schema(),
                query,
-               inputs,
+               inputs)
-               limit)
     }
 
     /// Transact entities against the Mentat store, using the given connection and the current

src/query.rs

@@ -59,25 +59,21 @@ pub type QueryExecutionResult = Result<QueryResults>;
 /// instances.
 /// The caller is responsible for ensuring that the SQLite connection has an open transaction if
 /// isolation is required.
-pub fn q_once<'sqlite, 'schema, 'query, T, U>
+pub fn q_once<'sqlite, 'schema, 'query, T>
 (sqlite: &'sqlite rusqlite::Connection,
  schema: &'schema Schema,
  query: &'query str,
- inputs: T,
+ inputs: T) -> QueryExecutionResult
- limit: U) -> QueryExecutionResult
+        where T: Into<Option<QueryInputs>>
-        where T: Into<Option<QueryInputs>>,
-              U: Into<Option<u64>>
 {
     let parsed = parse_find_string(query)?;
-    let mut algebrized = algebrize_with_inputs(schema, parsed, 0, inputs.into().unwrap_or(QueryInputs::default()))?;
+    let algebrized = algebrize_with_inputs(schema, parsed, 0, inputs.into().unwrap_or(QueryInputs::default()))?;
 
     if algebrized.is_known_empty() {
         // We don't need to do any SQL work at all.
         return Ok(QueryResults::empty(&algebrized.find_spec));
     }
 
-    algebrized.apply_limit(limit.into());
-
     // Because this is q_once, we can check that all of our `:in` variables are bound at this point.
     // If they aren't, the user has made an error -- perhaps writing the wrong variable in `:in`, or
     // not binding in the `QueryInput`.

tests/query.rs

@@ -41,7 +41,7 @@ fn test_rel() {
     // Rel.
     let start = time::PreciseTime::now();
     let results = q_once(&c, &db.schema,
-                         "[:find ?x ?ident :where [?x :db/ident ?ident]]", None, None)
+                         "[:find ?x ?ident :where [?x :db/ident ?ident]]", None)
         .expect("Query failed");
     let end = time::PreciseTime::now();
 
@@ -71,7 +71,7 @@ fn test_failing_scalar() {
     // Scalar that fails.
     let start = time::PreciseTime::now();
     let results = q_once(&c, &db.schema,
-                         "[:find ?x . :where [?x :db/fulltext true]]", None, None)
+                         "[:find ?x . :where [?x :db/fulltext true]]", None)
         .expect("Query failed");
     let end = time::PreciseTime::now();
 
@@ -93,7 +93,7 @@ fn test_scalar() {
     // Scalar that succeeds.
     let start = time::PreciseTime::now();
     let results = q_once(&c, &db.schema,
-                         "[:find ?ident . :where [24 :db/ident ?ident]]", None, None)
+                         "[:find ?ident . :where [24 :db/ident ?ident]]", None)
         .expect("Query failed");
     let end = time::PreciseTime::now();
 
@@ -123,7 +123,7 @@ fn test_tuple() {
                          "[:find [?index ?cardinality]
                            :where [:db/txInstant :db/index ?index]
                                   [:db/txInstant :db/cardinality ?cardinality]]",
-                         None, None)
+                         None)
         .expect("Query failed");
     let end = time::PreciseTime::now();
 
@@ -150,7 +150,7 @@ fn test_coll() {
     // Coll.
     let start = time::PreciseTime::now();
     let results = q_once(&c, &db.schema,
-                         "[:find [?e ...] :where [?e :db/ident _]]", None, None)
+                         "[:find [?e ...] :where [?e :db/ident _]]", None)
         .expect("Query failed");
     let end = time::PreciseTime::now();
 
@@ -175,7 +175,7 @@ fn test_inputs() {
     let ee = (Variable::from_valid_name("?e"), TypedValue::Ref(5));
     let inputs = QueryInputs::with_value_sequence(vec![ee]);
     let results = q_once(&c, &db.schema,
-                         "[:find ?i . :in ?e :where [?e :db/ident ?i]]", inputs, None)
+                         "[:find ?i . :in ?e :where [?e :db/ident ?i]]", inputs)
                         .expect("query to succeed");
 
     if let QueryResults::Scalar(Some(TypedValue::Keyword(value))) = results {
@@ -195,7 +195,7 @@ fn test_unbound_inputs() {
     let xx = (Variable::from_valid_name("?x"), TypedValue::Ref(5));
     let inputs = QueryInputs::with_value_sequence(vec![xx]);
     let results = q_once(&c, &db.schema,
-                         "[:find ?i . :in ?e :where [?e :db/ident ?i]]", inputs, None);
+                         "[:find ?i . :in ?e :where [?e :db/ident ?i]]", inputs);
 
     match results {
         Result::Err(Error(ErrorKind::UnboundVariables(vars), _)) => {