Extend inequalities to Instants. (#439) r=fluffyemily,nalexander

query-algebrizer/src/clauses/convert.rs

@@ -51,6 +51,53 @@ macro_rules! coerce_to_typed_value {
     } }
 }
 
+pub trait ValueTypes {
+    fn potential_types(&self, schema: &Schema) -> Result<ValueTypeSet>;
+}
+
+impl ValueTypes for FnArg {
+    fn potential_types(&self, schema: &Schema) -> Result<ValueTypeSet> {
+        Ok(match self {
+                &FnArg::EntidOrInteger(x) => {
+                    if ValueType::Ref.accommodates_integer(x) {
+                        // TODO: also see if it's a valid entid?
+                        ValueTypeSet::of_longs()
+                    } else {
+                        ValueTypeSet::of_one(ValueType::Long)
+                    }
+                },
+
+                &FnArg::IdentOrKeyword(ref x) => {
+                    if schema.get_entid(x).is_some() {
+                        ValueTypeSet::of_keywords()
+                    } else {
+                        ValueTypeSet::of_one(ValueType::Keyword)
+                    }
+                },
+
+                &FnArg::Variable(_) => {
+                    ValueTypeSet::any()
+                },
+
+                &FnArg::Constant(NonIntegerConstant::BigInteger(_)) => {
+                    // Not yet implemented.
+                    bail!(ErrorKind::UnsupportedArgument)
+                },
+
+                // These don't make sense here. TODO: split FnArg into scalar and non-scalar…
+                &FnArg::Vector(_) |
+                &FnArg::SrcVar(_) => bail!(ErrorKind::UnsupportedArgument),
+
+                // These are all straightforward.
+                &FnArg::Constant(NonIntegerConstant::Boolean(_)) => ValueTypeSet::of_one(ValueType::Boolean),
+                &FnArg::Constant(NonIntegerConstant::Instant(_)) => ValueTypeSet::of_one(ValueType::Instant),
+                &FnArg::Constant(NonIntegerConstant::Uuid(_)) => ValueTypeSet::of_one(ValueType::Uuid),
+                &FnArg::Constant(NonIntegerConstant::Float(_)) => ValueTypeSet::of_one(ValueType::Double),
+                &FnArg::Constant(NonIntegerConstant::Text(_)) => ValueTypeSet::of_one(ValueType::String),
+            })
+    }
+}
+
 pub enum ValueConversion {
     Val(TypedValue),
     Impossible(EmptyBecause),

query-algebrizer/src/clauses/not.rs

@@ -109,7 +109,7 @@ mod testing {
         ColumnIntersection, 
         DatomsColumn, 
         DatomsTable, 
-        NumericComparison, 
+        Inequality,
         QualifiedAlias,
         QueryValue, 
         SourceAlias, 
@@ -364,8 +364,8 @@ mod testing {
         assert!(!cc.is_known_empty());
         assert_eq!(cc.wheres, ColumnIntersection(vec![
                 ColumnConstraintOrAlternation::Constraint(ColumnConstraint::Equals(d0a.clone(), age.clone())),
-                ColumnConstraintOrAlternation::Constraint(ColumnConstraint::NumericInequality {
+                ColumnConstraintOrAlternation::Constraint(ColumnConstraint::Inequality {
-                    operator: NumericComparison::LessThan,
+                    operator: Inequality::LessThan,
                     left: QueryValue::Column(d0v.clone()),
                     right: QueryValue::TypedValue(TypedValue::Long(30)),
                 }),

query-algebrizer/src/clauses/or.rs

@@ -751,7 +751,7 @@ mod testing {
         ColumnConstraint,
         DatomsColumn,
         DatomsTable,
-        NumericComparison,
+        Inequality,
         QualifiedAlias,
         QueryValue,
         SourceAlias,
@@ -960,8 +960,8 @@ mod testing {
         assert!(!cc.is_known_empty());
         assert_eq!(cc.wheres, ColumnIntersection(vec![
             ColumnConstraintOrAlternation::Constraint(ColumnConstraint::Equals(d0a.clone(), age.clone())),
-            ColumnConstraintOrAlternation::Constraint(ColumnConstraint::NumericInequality {
+            ColumnConstraintOrAlternation::Constraint(ColumnConstraint::Inequality {
-                operator: NumericComparison::LessThan,
+                operator: Inequality::LessThan,
                 left: QueryValue::Column(d0v.clone()),
                 right: QueryValue::TypedValue(TypedValue::Long(30)),
             }),

query-algebrizer/src/clauses/predicate.rs

@@ -10,14 +10,18 @@
 
 use mentat_core::{
     Schema,
+    ValueType,
 };
 
 use mentat_query::{
+    FnArg,
     Predicate,
 };
 
 use clauses::ConjoiningClauses;
 
+use clauses::convert::ValueTypes;
+
 use errors::{
     Result,
     ErrorKind,
@@ -25,7 +29,9 @@ use errors::{
 
 use types::{
     ColumnConstraint,
-    NumericComparison,
+    EmptyBecause,
+    Inequality,
+    ValueTypeSet,
 };
 
 /// Application of predicates.
@@ -39,19 +45,25 @@ impl ConjoiningClauses {
     pub fn apply_predicate<'s>(&mut self, schema: &'s Schema, predicate: Predicate) -> Result<()> {
         // Because we'll be growing the set of built-in predicates, handling each differently,
         // and ultimately allowing user-specified predicates, we match on the predicate name first.
-        if let Some(op) = NumericComparison::from_datalog_operator(predicate.operator.0.as_str()) {
+        if let Some(op) = Inequality::from_datalog_operator(predicate.operator.0.as_str()) {
-            self.apply_numeric_predicate(schema, op, predicate)
+            self.apply_inequality(schema, op, predicate)
         } else {
             bail!(ErrorKind::UnknownFunction(predicate.operator.clone()))
         }
     }
 
+    fn potential_types(&self, schema: &Schema, fn_arg: &FnArg) -> Result<ValueTypeSet> {
+        match fn_arg {
+            &FnArg::Variable(ref v) => Ok(self.known_type_set(v)),
+            _ => fn_arg.potential_types(schema),
+        }
+    }
+
     /// This function:
     /// - Resolves variables and converts types to those more amenable to SQL.
     /// - Ensures that the predicate functions name a known operator.
-    /// - Accumulates a `NumericInequality` constraint into the `wheres` list.
+    /// - Accumulates an `Inequality` constraint into the `wheres` list.
-    #[allow(unused_variables)]
+    pub fn apply_inequality<'s>(&mut self, schema: &'s Schema, comparison: Inequality, predicate: Predicate) -> Result<()> {
-    pub fn apply_numeric_predicate<'s>(&mut self, schema: &'s Schema, comparison: NumericComparison, predicate: Predicate) -> Result<()> {
         if predicate.args.len() != 2 {
             bail!(ErrorKind::InvalidNumberOfArguments(predicate.operator.clone(), predicate.args.len(), 2));
         }
@@ -60,21 +72,74 @@ impl ConjoiningClauses {
         // Any variables that aren't bound by this point in the linear processing of clauses will
         // cause the application of the predicate to fail.
         let mut args = predicate.args.into_iter();
-        let left = self.resolve_numeric_argument(&predicate.operator, 0, args.next().unwrap())?;
+        let left = args.next().expect("two args");
-        let right = self.resolve_numeric_argument(&predicate.operator, 1, args.next().unwrap())?;
+        let right = args.next().expect("two args");
 
-        // These arguments must be variables or numeric constants.
-        // TODO: generalize argument resolution and validation for different kinds of predicates:
-        // as we process `(< ?x 5)` we are able to check or deduce that `?x` is numeric, and either
-        // simplify the pattern or optimize the rest of the query.
-        // To do so needs a slightly more sophisticated representation of type constraints — a set,
-        // not a single `Option`.
 
+        // The types we're handling here must be the intersection of the possible types of the arguments,
+        // the known types of any variables, and the types supported by our inequality operators.
+        let supported_types = comparison.supported_types();
+        let mut left_types = self.potential_types(schema, &left)?
+                                 .intersection(&supported_types);
+        if left_types.is_empty() {
+            bail!(ErrorKind::InvalidArgument(predicate.operator.clone(), "numeric or instant", 0));
+        }
+
+        let mut right_types = self.potential_types(schema, &right)?
+                                  .intersection(&supported_types);
+        if right_types.is_empty() {
+            bail!(ErrorKind::InvalidArgument(predicate.operator.clone(), "numeric or instant", 1));
+        }
+
+        // We would like to allow longs to compare to doubles.
+        // Do this by expanding the type sets. `resolve_numeric_argument` will
+        // use `Long` by preference.
+        if right_types.contains(ValueType::Long) {
+            right_types.insert(ValueType::Double);
+        }
+        if left_types.contains(ValueType::Long) {
+            left_types.insert(ValueType::Double);
+        }
+
+        let shared_types = left_types.intersection(&right_types);
+        if shared_types.is_empty() {
+            // In isolation these are both valid inputs to the operator, but the query cannot
+            // succeed because the types don't match.
+            self.mark_known_empty(
+                if let Some(var) = left.as_variable().or_else(|| right.as_variable()) {
+                    EmptyBecause::TypeMismatch {
+                        var: var.clone(),
+                        existing: left_types,
+                        desired: right_types,
+                    }
+                } else {
+                    EmptyBecause::KnownTypeMismatch {
+                        left: left_types,
+                        right: right_types,
+                    }
+                });
+            return Ok(());
+        }
+
+        // We expect the intersection to be Long, Long+Double, Double, or Instant.
+        let left_v;
+        let right_v;
+        if shared_types == ValueTypeSet::of_one(ValueType::Instant) {
+            left_v = self.resolve_instant_argument(&predicate.operator, 0, left)?;
+            right_v = self.resolve_instant_argument(&predicate.operator, 1, right)?;
+        } else if !shared_types.is_empty() && shared_types.is_subset(&ValueTypeSet::of_numeric_types()) {
+            left_v = self.resolve_numeric_argument(&predicate.operator, 0, left)?;
+            right_v = self.resolve_numeric_argument(&predicate.operator, 1, right)?;
+        } else {
+            bail!(ErrorKind::InvalidArgument(predicate.operator.clone(), "numeric or instant", 0));
+        }
+
+        // These arguments must be variables or instant/numeric constants.
         // TODO: static evaluation. #383.
-        let constraint = ColumnConstraint::NumericInequality {
+        let constraint = ColumnConstraint::Inequality {
             operator: comparison,
-            left: left,
+            left: left_v,
-            right: right,
+            right: right_v,
         };
         self.wheres.add_intersection(constraint);
         Ok(())
@@ -119,7 +184,7 @@ mod testing {
     /// Apply two patterns: a pattern and a numeric predicate.
     /// Verify that after application of the predicate we know that the value
     /// must be numeric.
-    fn test_apply_numeric_predicate() {
+    fn test_apply_inequality() {
         let mut cc = ConjoiningClauses::default();
         let mut schema = Schema::default();
 
@@ -141,8 +206,8 @@ mod testing {
         assert!(!cc.is_known_empty());
 
         let op = PlainSymbol::new("<");
-        let comp = NumericComparison::from_datalog_operator(op.plain_name()).unwrap();
+        let comp = Inequality::from_datalog_operator(op.plain_name()).unwrap();
-        assert!(cc.apply_numeric_predicate(&schema, comp, Predicate {
+        assert!(cc.apply_inequality(&schema, comp, Predicate {
              operator: op,
              args: vec![
                 FnArg::Variable(Variable::from_valid_name("?y")), FnArg::EntidOrInteger(10),
@@ -162,8 +227,8 @@ mod testing {
 
         let clauses = cc.wheres;
         assert_eq!(clauses.len(), 1);
-        assert_eq!(clauses.0[0], ColumnConstraint::NumericInequality {
+        assert_eq!(clauses.0[0], ColumnConstraint::Inequality {
-            operator: NumericComparison::LessThan,
+            operator: Inequality::LessThan,
             left: QueryValue::Column(cc.column_bindings.get(&y).unwrap()[0].clone()),
             right: QueryValue::TypedValue(TypedValue::Long(10)),
         }.into());
@@ -201,8 +266,8 @@ mod testing {
         assert!(!cc.is_known_empty());
 
         let op = PlainSymbol::new(">=");
-        let comp = NumericComparison::from_datalog_operator(op.plain_name()).unwrap();
+        let comp = Inequality::from_datalog_operator(op.plain_name()).unwrap();
-        assert!(cc.apply_numeric_predicate(&schema, comp, Predicate {
+        assert!(cc.apply_inequality(&schema, comp, Predicate {
              operator: op,
              args: vec![
                 FnArg::Variable(Variable::from_valid_name("?y")), FnArg::EntidOrInteger(10),

query-algebrizer/src/clauses/resolve.rs

@@ -10,6 +10,7 @@
 
 use mentat_core::{
     TypedValue,
+    ValueType,
 };
 
 use mentat_query::{
@@ -55,7 +56,7 @@ impl ConjoiningClauses {
             Constant(NonIntegerConstant::Boolean(_)) |
             Constant(NonIntegerConstant::Text(_)) |
             Constant(NonIntegerConstant::Uuid(_)) |
-            Constant(NonIntegerConstant::Instant(_)) |        // Instants are covered elsewhere.
+            Constant(NonIntegerConstant::Instant(_)) |        // Instants are covered below.
             Constant(NonIntegerConstant::BigInteger(_)) |
             Vector(_) => {
                 self.mark_known_empty(EmptyBecause::NonNumericArgument);
@@ -65,6 +66,36 @@ impl ConjoiningClauses {
         }
     }
 
+    /// Just like `resolve_numeric_argument`, but for `ValueType::Instant`.
+    pub fn resolve_instant_argument(&mut self, function: &PlainSymbol, position: usize, arg: FnArg) -> Result<QueryValue> {
+        use self::FnArg::*;
+        match arg {
+            FnArg::Variable(var) => {
+                self.constrain_var_to_type(var.clone(), ValueType::Instant);
+                self.column_bindings
+                    .get(&var)
+                    .and_then(|cols| cols.first().map(|col| QueryValue::Column(col.clone())))
+                    .ok_or_else(|| Error::from_kind(ErrorKind::UnboundVariable(var.name())))
+            },
+            Constant(NonIntegerConstant::Instant(v)) => {
+                Ok(QueryValue::TypedValue(TypedValue::Instant(v)))
+            },
+
+            // TODO: should we allow integers if they seem to be timestamps? It's ambiguous…
+            EntidOrInteger(_) |
+            IdentOrKeyword(_) |
+            SrcVar(_) |
+            Constant(NonIntegerConstant::Boolean(_)) |
+            Constant(NonIntegerConstant::Float(_)) |
+            Constant(NonIntegerConstant::Text(_)) |
+            Constant(NonIntegerConstant::Uuid(_)) |
+            Constant(NonIntegerConstant::BigInteger(_)) |
+            Vector(_) => {
+                self.mark_known_empty(EmptyBecause::NonInstantArgument);
+                bail!(ErrorKind::InvalidArgument(function.clone(), "instant", position));
+            },
+        }
+    }
 
     /// Take a function argument and turn it into a `QueryValue` suitable for use in a concrete
     /// constraint.

query-algebrizer/src/errors.rs

@@ -39,6 +39,11 @@ error_chain! {
     }
 
     errors {
+        UnsupportedArgument {
+            description("unexpected FnArg")
+            display("unexpected FnArg")
+        }
+
         InputTypeDisagreement(var: PlainSymbol, declared: ValueType, provided: ValueType) {
             description("input type disagreement")
             display("value of type {} provided for var {}, expected {}", provided, var, declared)

query-algebrizer/src/lib.rs

@@ -56,6 +56,11 @@ pub use clauses::{
     QueryInputs,
 };
 
+pub use types::{
+    EmptyBecause,
+    ValueTypeSet,
+};
+
 #[derive(Debug)]
 pub struct AlgebraicQuery {
     default_source: SrcVar,

query-algebrizer/src/types.rs

@@ -274,10 +274,11 @@ impl From<Order> for OrderBy {
 }
 
 #[derive(Copy, Clone, PartialEq, Eq)]
-/// Define the different numeric inequality operators that we support.
+/// Define the different inequality operators that we support.
 /// Note that we deliberately don't just use "<=" and friends as strings:
 /// Datalog and SQL don't use the same operators (e.g., `<>` and `!=`).
-pub enum NumericComparison {
+/// These are applicable to numbers and instants.
+pub enum Inequality {
     LessThan,
     LessThanOrEquals,
     GreaterThan,
@@ -285,9 +286,9 @@ pub enum NumericComparison {
     NotEquals,
 }
 
-impl NumericComparison {
+impl Inequality {
     pub fn to_sql_operator(self) -> &'static str {
-        use self::NumericComparison::*;
+        use self::Inequality::*;
         match self {
             LessThan            => "<",
             LessThanOrEquals    => "<=",
@@ -297,21 +298,28 @@ impl NumericComparison {
         }
     }
 
-    pub fn from_datalog_operator(s: &str) -> Option<NumericComparison> {
+    pub fn from_datalog_operator(s: &str) -> Option<Inequality> {
         match s {
-            "<"  => Some(NumericComparison::LessThan),
+            "<"  => Some(Inequality::LessThan),
-            "<=" => Some(NumericComparison::LessThanOrEquals),
+            "<=" => Some(Inequality::LessThanOrEquals),
-            ">"  => Some(NumericComparison::GreaterThan),
+            ">"  => Some(Inequality::GreaterThan),
-            ">=" => Some(NumericComparison::GreaterThanOrEquals),
+            ">=" => Some(Inequality::GreaterThanOrEquals),
-            "!=" => Some(NumericComparison::NotEquals),
+            "!=" => Some(Inequality::NotEquals),
             _    => None,
         }
     }
+
+    // The built-in inequality operators apply to Long, Double, and Instant.
+    pub fn supported_types(&self) -> ValueTypeSet {
+        let mut ts = ValueTypeSet::of_numeric_types();
+        ts.insert(ValueType::Instant);
+        ts
+    }
 }
 
-impl Debug for NumericComparison {
+impl Debug for Inequality {
     fn fmt(&self, f: &mut Formatter) -> ::std::fmt::Result {
-        use self::NumericComparison::*;
+        use self::Inequality::*;
         f.write_str(match self {
             &LessThan => "<",
             &LessThanOrEquals => "<=",
@@ -325,15 +333,13 @@ impl Debug for NumericComparison {
 #[derive(PartialEq, Eq)]
 pub enum ColumnConstraint {
     Equals(QualifiedAlias, QueryValue),
-    NumericInequality {
+    Inequality {
-        operator: NumericComparison,
+        operator: Inequality,
         left: QueryValue,
         right: QueryValue,
     },
     HasType(TableAlias, ValueType),
     NotExists(ComputedTable),
-    // TODO: Merge this with NumericInequality?  I expect the fine-grained information to be
-    // valuable when optimizing.
     Matches(QualifiedAlias, QueryValue),
 }
 
@@ -441,7 +447,7 @@ impl Debug for ColumnConstraint {
                 write!(f, "{:?} = {:?}", qa1, thing)
             },
 
-            &NumericInequality { operator, ref left, ref right } => {
+            &Inequality { operator, ref left, ref right } => {
                 write!(f, "{:?} {:?} {:?}", left, operator, right)
             },
 
@@ -462,9 +468,15 @@ impl Debug for ColumnConstraint {
 #[derive(PartialEq, Clone)]
 pub enum EmptyBecause {
     ConflictingBindings { var: Variable, existing: TypedValue, desired: TypedValue },
+
+    // A variable is known to be of two conflicting sets of types.
     TypeMismatch { var: Variable, existing: ValueTypeSet, desired: ValueTypeSet },
+
+    // The same, but for non-variables.
+    KnownTypeMismatch { left: ValueTypeSet, right: ValueTypeSet },
     NoValidTypes(Variable),
     NonAttributeArgument,
+    NonInstantArgument,
     NonNumericArgument,
     NonStringFulltextValue,
     UnresolvedIdent(NamespacedKeyword),
@@ -487,12 +499,19 @@ impl Debug for EmptyBecause {
                 write!(f, "Type mismatch: {:?} can't be {:?}, because it's already {:?}",
                        var, desired, existing)
             },
+            &KnownTypeMismatch { ref left, ref right } => {
+                write!(f, "Type mismatch: {:?} can't be compared to {:?}",
+                       left, right)
+            },
             &NoValidTypes(ref var) => {
                 write!(f, "Type mismatch: {:?} has no valid types", var)
             },
             &NonAttributeArgument => {
                 write!(f, "Non-attribute argument in attribute place")
             },
+            &NonInstantArgument => {
+                write!(f, "Non-instant argument in instant place")
+            },
             &NonNumericArgument => {
                 write!(f, "Non-numeric argument in numeric place")
             },
@@ -612,6 +631,10 @@ impl ValueTypeSet {
         self.0.iter().next()
     }
 
+    pub fn is_subset(&self, other: &ValueTypeSet) -> bool {
+        self.0.is_subset(&other.0)
+    }
+
     pub fn contains(&self, vt: ValueType) -> bool {
         self.0.contains(&vt)
     }

query-algebrizer/tests/predicate.rs

@@ -0,0 +1,149 @@
+// Copyright 2016 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.
+
+extern crate mentat_core;
+extern crate mentat_query;
+extern crate mentat_query_algebrizer;
+extern crate mentat_query_parser;
+
+use std::collections::BTreeMap;
+
+use mentat_core::{
+    Attribute,
+    Entid,
+    Schema,
+    ValueType,
+    TypedValue,
+};
+
+use mentat_query_parser::{
+    parse_find_string,
+};
+
+use mentat_query::{
+    NamespacedKeyword,
+    PlainSymbol,
+    Variable,
+};
+
+use mentat_query_algebrizer::{
+    BindingError,
+    ConjoiningClauses,
+    ComputedTable,
+    EmptyBecause,
+    Error,
+    ErrorKind,
+    QueryInputs,
+    ValueTypeSet,
+    algebrize,
+    algebrize_with_inputs,
+};
+
+// These are helpers that tests use to build Schema instances.
+#[cfg(test)]
+fn associate_ident(schema: &mut Schema, i: NamespacedKeyword, e: Entid) {
+    schema.entid_map.insert(e, i.clone());
+    schema.ident_map.insert(i.clone(), e);
+}
+
+#[cfg(test)]
+fn add_attribute(schema: &mut Schema, e: Entid, a: Attribute) {
+    schema.schema_map.insert(e, a);
+}
+
+fn prepopulated_schema() -> Schema {
+    let mut schema = Schema::default();
+    associate_ident(&mut schema, NamespacedKeyword::new("foo", "date"), 65);
+    associate_ident(&mut schema, NamespacedKeyword::new("foo", "double"), 66);
+    add_attribute(&mut schema, 65, Attribute {
+        value_type: ValueType::Instant,
+        multival: false,
+        ..Default::default()
+    });
+    add_attribute(&mut schema, 66, Attribute {
+        value_type: ValueType::Double,
+        multival: false,
+        ..Default::default()
+    });
+    schema
+}
+
+fn bails(schema: &Schema, input: &str) -> Error {
+    let parsed = parse_find_string(input).expect("query input to have parsed");
+    algebrize(schema.into(), parsed).expect_err("algebrize to have failed")
+}
+
+fn bails_with_inputs(schema: &Schema, input: &str, inputs: QueryInputs) -> Error {
+    let parsed = parse_find_string(input).expect("query input to have parsed");
+    algebrize_with_inputs(schema, parsed, 0, inputs).expect_err("algebrize to have failed")
+}
+
+fn alg(schema: &Schema, input: &str) -> ConjoiningClauses {
+    let parsed = parse_find_string(input).expect("query input to have parsed");
+    algebrize(schema.into(), parsed).expect("algebrizing to have succeeded").cc
+}
+
+#[test]
+fn test_instant_predicates_require_instants() {
+    let schema = prepopulated_schema();
+
+    // You can't use a string for an inequality: this is a straight-up error.
+    let query = r#"[:find ?e
+                    :where
+                    [?e :foo/date ?t]
+                    [(> ?t "2017-06-16T00:56:41.257Z")]]"#;
+    match bails(&schema, query).0 {
+        ErrorKind::InvalidArgument(op, why, idx) => {
+            assert_eq!(op, PlainSymbol::new(">"));
+            assert_eq!(why, "numeric or instant");
+            assert_eq!(idx, 1);
+        },
+        _ => panic!("Expected InvalidArgument."),
+    }
+
+    let query = r#"[:find ?e
+                    :where
+                    [?e :foo/date ?t]
+                    [(> "2017-06-16T00:56:41.257Z", ?t)]]"#;
+    match bails(&schema, query).0 {
+        ErrorKind::InvalidArgument(op, why, idx) => {
+            assert_eq!(op, PlainSymbol::new(">"));
+            assert_eq!(why, "numeric or instant");
+            assert_eq!(idx, 0);                      // We get this right.
+        },
+        _ => panic!("Expected InvalidArgument."),
+    }
+
+    // You can try using a number, which is valid input to a numeric predicate.
+    // In this store and query, though, that means we expect `?t` to be both
+    // an instant and a number, so the query is known-empty.
+    let query = r#"[:find ?e
+                    :where
+                    [?e :foo/date ?t]
+                    [(> ?t 1234512345)]]"#;
+    let cc = alg(&schema, query);
+    assert!(cc.is_known_empty());
+    assert_eq!(cc.empty_because.unwrap(),
+               EmptyBecause::TypeMismatch {
+                   var: Variable::from_valid_name("?t"),
+                   existing: ValueTypeSet::of_one(ValueType::Instant),
+                   desired: ValueTypeSet::of_numeric_types(),
+    });
+
+    // You can compare doubles to longs.
+    let query = r#"[:find ?e
+                    :where
+                    [?e :foo/double ?t]
+                    [(< ?t 1234512345)]]"#;
+    let cc = alg(&schema, query);
+    assert!(!cc.is_known_empty());
+    assert_eq!(cc.known_type(&Variable::from_valid_name("?t")).expect("?t is known"),
+               ValueType::Double);
+}

query-translator/src/translate.rs

@@ -140,7 +140,7 @@ impl ToConstraint for ColumnConstraint {
                 }
             },
 
-            NumericInequality { operator, left, right } => {
+            Inequality { operator, left, right } => {
                 Constraint::Infix {
                     op: Op(operator.to_sql_operator()),
                     left: left.into(),

query-translator/tests/translate.rs

@@ -317,6 +317,56 @@ fn test_numeric_not_equals_known_attribute() {
     assert_eq!(args, vec![]);
 }
 
+#[test]
+fn test_compare_long_to_double_constants() {
+    let schema = prepopulated_typed_schema(ValueType::Double);
+
+    let query = r#"[:find ?e .
+                    :where
+                    [?e :foo/bar ?v]
+                    [(< 99.0 1234512345)]]"#;
+    let SQLQuery { sql, args } = translate(&schema, query);
+    assert_eq!(sql, "SELECT `datoms00`.e AS `?e` FROM `datoms` AS `datoms00` \
+                     WHERE `datoms00`.a = 99 \
+                       AND 9.9e1 < 1234512345 \
+                     LIMIT 1");
+    assert_eq!(args, vec![]);
+}
+
+#[test]
+fn test_compare_long_to_double() {
+    let schema = prepopulated_typed_schema(ValueType::Double);
+
+    // You can compare longs to doubles.
+    let query = r#"[:find ?e .
+                    :where
+                    [?e :foo/bar ?t]
+                    [(< ?t 1234512345)]]"#;
+    let SQLQuery { sql, args } = translate(&schema, query);
+    assert_eq!(sql, "SELECT `datoms00`.e AS `?e` FROM `datoms` AS `datoms00` \
+                     WHERE `datoms00`.a = 99 \
+                       AND `datoms00`.v < 1234512345 \
+                     LIMIT 1");
+    assert_eq!(args, vec![]);
+}
+
+#[test]
+fn test_compare_double_to_long() {
+    let schema = prepopulated_typed_schema(ValueType::Long);
+
+    // You can compare doubles to longs.
+    let query = r#"[:find ?e .
+                    :where
+                    [?e :foo/bar ?t]
+                    [(< ?t 1234512345.0)]]"#;
+    let SQLQuery { sql, args } = translate(&schema, query);
+    assert_eq!(sql, "SELECT `datoms00`.e AS `?e` FROM `datoms` AS `datoms00` \
+                     WHERE `datoms00`.a = 99 \
+                       AND `datoms00`.v < 1.234512345e9 \
+                     LIMIT 1");
+    assert_eq!(args, vec![]);
+}
+
 #[test]
 fn test_simple_or_join() {
     let mut schema = Schema::default();
@@ -888,3 +938,20 @@ fn test_fulltext_inputs() {
                        AND `datoms02`.a = 99");
     assert_eq!(args, vec![make_arg("$v0", "hello"),]);
 }
+
+#[test]
+fn test_instant_range() {
+    let schema = prepopulated_typed_schema(ValueType::Instant);
+    let query = r#"[:find ?e
+                    :where
+                    [?e :foo/bar ?t]
+                    [(> ?t #inst "2017-06-16T00:56:41.257Z")]]"#;
+
+    let SQLQuery { sql, args } = translate(&schema, query);
+    assert_eq!(sql, "SELECT DISTINCT `datoms00`.e AS `?e` \
+                     FROM \
+                     `datoms` AS `datoms00` \
+                     WHERE `datoms00`.a = 99 \
+                       AND `datoms00`.v > 1497574601257000");
+    assert_eq!(args, vec![]);
+}

query/src/lib.rs

@@ -259,6 +259,15 @@ impl FromValue<FnArg> for FnArg {
     }
 }
 
+impl FnArg {
+    pub fn as_variable(&self) -> Option<&Variable> {
+        match self {
+            &FnArg::Variable(ref v) => Some(v),
+            _ => None,
+        }
+    }
+}
+
 /// e, a, tx can't be values -- no strings, no floats -- and so
 /// they can only be variables, entity IDs, ident keywords, or
 /// placeholders.

tests/query.rs

@@ -356,3 +356,37 @@ fn test_fulltext() {
         _ => panic!("Expected query to work."),
     }
 }
+
+#[test]
+fn test_instant_range_query() {
+    let mut c = new_connection("").expect("Couldn't open conn.");
+    let mut conn = Conn::connect(&mut c).expect("Couldn't open DB.");
+
+    conn.transact(&mut c, r#"[
+        [:db/add "a" :db/ident :foo/date]
+        [:db/add "a" :db/valueType :db.type/instant]
+        [:db/add "a" :db/cardinality :db.cardinality/one]
+    ]"#).unwrap();
+
+    let ids = conn.transact(&mut c, r#"[
+        [:db/add "b" :foo/date #inst "2016-01-01T11:00:00.000Z"]
+        [:db/add "c" :foo/date #inst "2016-06-01T11:00:01.000Z"]
+        [:db/add "d" :foo/date #inst "2017-01-01T11:00:02.000Z"]
+        [:db/add "e" :foo/date #inst "2017-06-01T11:00:03.000Z"]
+    ]"#).unwrap().tempids;
+
+    let r = conn.q_once(&mut c,
+                        r#"[:find [?x ...]
+                            :order (asc ?date)
+                            :where
+                            [?x :foo/date ?date]
+                            [(< ?date #inst "2017-01-01T11:00:02.000Z")]]"#, None);
+    match r {
+        Result::Ok(QueryResults::Coll(vals)) => {
+            assert_eq!(vals,
+                       vec![TypedValue::Ref(*ids.get("b").unwrap()),
+                            TypedValue::Ref(*ids.get("c").unwrap())]);
+        },
+        _ => panic!("Expected query to work."),
+    }
+}