Parse :in, pass inputs through to querying. (#418) r=nalexander

This commit downgrades error_chain to 0.8.1 in order to fix trait bounds
on errors.

Cargo.toml

@@ -18,7 +18,7 @@ rustc_version = "0.1.7"
 
 [dependencies]
 clap = "2.19.3"
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 nickel = "0.9.0"
 slog = "1.4.0"
 slog-scope = "0.2.2"

core/src/lib.rs

@@ -17,6 +17,7 @@ extern crate edn;
 pub mod values;
 
 use std::collections::BTreeMap;
+use std::fmt;
 use std::rc::Rc;
 use self::ordered_float::OrderedFloat;
 use self::edn::NamespacedKeyword;
@@ -44,19 +45,33 @@ pub enum ValueType {
 }
 
 impl ValueType {
-    pub fn to_edn_value(&self) -> edn::Value {
+    pub fn to_edn_value(self) -> edn::Value {
         match self {
-            &ValueType::Ref => values::DB_TYPE_REF.clone(),
+            ValueType::Ref => values::DB_TYPE_REF.clone(),
-            &ValueType::Boolean => values::DB_TYPE_BOOLEAN.clone(),
+            ValueType::Boolean => values::DB_TYPE_BOOLEAN.clone(),
-            &ValueType::Instant => values::DB_TYPE_INSTANT.clone(),
+            ValueType::Instant => values::DB_TYPE_INSTANT.clone(),
-            &ValueType::Long => values::DB_TYPE_LONG.clone(),
+            ValueType::Long => values::DB_TYPE_LONG.clone(),
-            &ValueType::Double => values::DB_TYPE_DOUBLE.clone(),
+            ValueType::Double => values::DB_TYPE_DOUBLE.clone(),
-            &ValueType::String => values::DB_TYPE_STRING.clone(),
+            ValueType::String => values::DB_TYPE_STRING.clone(),
-            &ValueType::Keyword => values::DB_TYPE_KEYWORD.clone(),
+            ValueType::Keyword => values::DB_TYPE_KEYWORD.clone(),
         }
     }
 }
 
+impl fmt::Display for ValueType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", match *self {
+            ValueType::Ref =>     "db.type/ref",
+            ValueType::Boolean => "db.type/boolean",
+            ValueType::Instant => "db.type/instant",
+            ValueType::Long =>    "db.type/long",
+            ValueType::Double =>  "db.type/double",
+            ValueType::String =>  "db.type/string",
+            ValueType::Keyword => "db.type/keyword",
+        })
+    }
+}
+
 /// Represents a Mentat value in a particular value set.
 // TODO: expand to include :db.type/{instant,url,uuid}.
 // TODO: BigInt?

db/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 itertools = "0.5.9"
 lazy_static = "0.2.2"
 ordered-float = "0.4.0"

query-algebrizer/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 
 [dependencies.mentat_core]
 path = "../core"

query-algebrizer/src/clauses/inputs.rs

@@ -0,0 +1,72 @@
+// 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.
+
+use std::collections::BTreeMap;
+
+use mentat_core::{
+    TypedValue,
+    ValueType,
+};
+
+use mentat_query::{
+    Variable,
+};
+
+pub use errors::{
+    Error,
+    ErrorKind,
+    Result,
+};
+
+/// Define the inputs to a query. This is in two parts: a set of values known now, and a set of
+/// types known now.
+/// The separate map of types is to allow queries to be algebrized without full knowledge of
+/// the bindings that will be used at execution time.
+/// When built correctly, `types` is guaranteed to contain the types of `values` -- use
+/// `QueryInputs::new` or `QueryInputs::with_values` to construct an instance.
+pub struct QueryInputs {
+    pub types: BTreeMap<Variable, ValueType>,
+    pub values: BTreeMap<Variable, TypedValue>,
+}
+
+impl Default for QueryInputs {
+    fn default() -> Self {
+        QueryInputs { types: BTreeMap::default(), values: BTreeMap::default() }
+    }
+}
+
+impl QueryInputs {
+    pub fn with_value_sequence(vals: Vec<(Variable, TypedValue)>) -> QueryInputs {
+        let values: BTreeMap<Variable, TypedValue> = vals.into_iter().collect();
+        QueryInputs::with_values(values)
+    }
+
+    pub fn with_values(values: BTreeMap<Variable, TypedValue>) -> QueryInputs {
+        QueryInputs {
+            types: values.iter().map(|(var, val)| (var.clone(), val.value_type())).collect(),
+            values: values,
+        }
+    }
+
+    pub fn new(mut types: BTreeMap<Variable, ValueType>,
+               values: BTreeMap<Variable, TypedValue>) -> Result<QueryInputs> {
+        // Make sure that the types of the values agree with those in types, and collect.
+        for (var, v) in values.iter() {
+            let t = v.value_type();
+            let old = types.insert(var.clone(), t);
+            if let Some(old) = old {
+                if old != t {
+                    bail!(ErrorKind::InputTypeDisagreement(var.name(), old, t));
+                }
+            }
+        }
+        Ok(QueryInputs { types: types, values: values })
+    }
+}

query-algebrizer/src/clauses/mod.rs

@@ -59,6 +59,7 @@ use types::{
     TableAlias,
 };
 
+mod inputs;
 mod or;
 mod pattern;
 mod predicate;
@@ -66,6 +67,8 @@ mod resolve;
 
 use validate::validate_or_join;
 
+pub use self::inputs::QueryInputs;
+
 // We do this a lot for errors.
 trait RcCloned<T> {
     fn cloned(&self) -> T;
@@ -89,6 +92,7 @@ trait Contains<K, T> {
 
 trait Intersection<K> {
     fn with_intersected_keys(&self, ks: &BTreeSet<K>) -> Self;
+    fn keep_intersected_keys(&mut self, ks: &BTreeSet<K>);
 }
 
 impl<K: Ord, T> Contains<K, T> for BTreeSet<K> {
@@ -108,6 +112,22 @@ impl<K: Clone + Ord, V: Clone> Intersection<K> for BTreeMap<K, V> {
             .filter_map(|(k, v)| ks.when_contains(k, || (k.clone(), v.clone())))
             .collect()
     }
+
+    /// Remove all keys from the map that are not present in `ks`.
+    /// This implementation is terrible because there's no mutable iterator for BTreeMap.
+    fn keep_intersected_keys(&mut self, ks: &BTreeSet<K>) {
+        let mut to_remove = Vec::with_capacity(self.len() - ks.len());
+        {
+        for k in self.keys() {
+            if !ks.contains(k) {
+                to_remove.push(k.clone())
+            }
+        }
+        }
+        for k in to_remove.into_iter() {
+            self.remove(&k);
+        }
+    }
 }
 
 /// A `ConjoiningClauses` (CC) is a collection of clauses that are combined with `JOIN`.
@@ -223,6 +243,38 @@ impl ConjoiningClauses {
             ..Default::default()
         }
     }
+
+    pub fn with_inputs<T>(in_variables: BTreeSet<Variable>, inputs: T) -> ConjoiningClauses
+    where T: Into<Option<QueryInputs>> {
+        ConjoiningClauses::with_inputs_and_alias_counter(in_variables, inputs, RcCounter::new())
+    }
+
+    pub fn with_inputs_and_alias_counter<T>(in_variables: BTreeSet<Variable>,
+                                            inputs: T,
+                                            alias_counter: RcCounter) -> ConjoiningClauses
+    where T: Into<Option<QueryInputs>> {
+        match inputs.into() {
+            None => ConjoiningClauses::with_alias_counter(alias_counter),
+            Some(QueryInputs { mut types, mut values }) => {
+                // Discard any bindings not mentioned in our :in clause.
+                types.keep_intersected_keys(&in_variables);
+                values.keep_intersected_keys(&in_variables);
+
+                let mut cc = ConjoiningClauses {
+                    alias_counter: alias_counter,
+                    input_variables: in_variables,
+                    value_bindings: values,
+                    ..Default::default()
+                };
+
+                // Pre-fill our type mappings with the types of the input bindings.
+                cc.known_types
+                  .extend(types.iter()
+                               .map(|(k, v)| (k.clone(), unit_type_set(*v))));
+                cc
+            },
+        }
+    }
 }
 
 /// Cloning.
@@ -254,28 +306,16 @@ impl ConjoiningClauses {
     }
 }
 
-impl ConjoiningClauses {
-    #[allow(dead_code)]
-    fn with_value_bindings(bindings: BTreeMap<Variable, TypedValue>) -> ConjoiningClauses {
-        let mut cc = ConjoiningClauses {
-            value_bindings: bindings,
-            ..Default::default()
-        };
-
-        // Pre-fill our type mappings with the types of the input bindings.
-        cc.known_types
-          .extend(cc.value_bindings
-                    .iter()
-                    .map(|(k, v)| (k.clone(), unit_type_set(v.value_type()))));
-        cc
-    }
-}
-
 impl ConjoiningClauses {
     pub fn bound_value(&self, var: &Variable) -> Option<TypedValue> {
         self.value_bindings.get(var).cloned()
     }
 
+    /// Return a set of the variables externally bound to values.
+    pub fn value_bound_variables(&self) -> BTreeSet<Variable> {
+        self.value_bindings.keys().cloned().collect()
+    }
+
     /// Return a single `ValueType` if the given variable is known to have a precise type.
     /// Returns `None` if the type of the variable is unknown.
     /// Returns `None` if the type of the variable is known but not precise -- "double

query-algebrizer/src/clauses/pattern.rs

@@ -270,6 +270,7 @@ mod testing {
     use super::*;
 
     use std::collections::BTreeMap;
+    use std::collections::BTreeSet;
     use std::rc::Rc;
 
     use mentat_core::attribute::Unique;
@@ -288,6 +289,7 @@ mod testing {
     };
 
     use clauses::{
+        QueryInputs,
         add_attribute,
         associate_ident,
         ident,
@@ -660,7 +662,9 @@ mod testing {
 
         let b: BTreeMap<Variable, TypedValue> =
             vec![(y.clone(), TypedValue::Boolean(true))].into_iter().collect();
-        let mut cc = ConjoiningClauses::with_value_bindings(b);
+        let inputs = QueryInputs::with_values(b);
+        let variables: BTreeSet<Variable> = vec![Variable::from_valid_name("?y")].into_iter().collect();
+        let mut cc = ConjoiningClauses::with_inputs(variables, inputs);
 
         cc.apply_pattern(&schema, Pattern {
             source: None,
@@ -705,7 +709,9 @@ mod testing {
 
         let b: BTreeMap<Variable, TypedValue> =
             vec![(y.clone(), TypedValue::Long(42))].into_iter().collect();
-        let mut cc = ConjoiningClauses::with_value_bindings(b);
+        let inputs = QueryInputs::with_values(b);
+        let variables: BTreeSet<Variable> = vec![Variable::from_valid_name("?y")].into_iter().collect();
+        let mut cc = ConjoiningClauses::with_inputs(variables, inputs);
 
         cc.apply_pattern(&schema, Pattern {
             source: None,
@@ -737,7 +743,9 @@ mod testing {
 
         let b: BTreeMap<Variable, TypedValue> =
             vec![(y.clone(), TypedValue::Long(42))].into_iter().collect();
-        let mut cc = ConjoiningClauses::with_value_bindings(b);
+        let inputs = QueryInputs::with_values(b);
+        let variables: BTreeSet<Variable> = vec![Variable::from_valid_name("?y")].into_iter().collect();
+        let mut cc = ConjoiningClauses::with_inputs(variables, inputs);
 
         cc.apply_pattern(&schema, Pattern {
             source: None,

query-algebrizer/src/errors.rs

@@ -10,6 +10,8 @@
 
 extern crate mentat_query;
 
+use mentat_core::ValueType;
+
 use self::mentat_query::{
     PlainSymbol,
 };
@@ -20,6 +22,11 @@ error_chain! {
     }
 
     errors {
+        InputTypeDisagreement(var: PlainSymbol, declared: ValueType, provided: ValueType) {
+            description("input type disagreement")
+            display("value of type {} provided for var {}, expected {}", provided, var, declared)
+        }
+
         UnknownFunction(name: PlainSymbol) {
             description("no such function")
             display("no function named {}", name)

query-algebrizer/src/lib.rs

@@ -15,6 +15,7 @@ extern crate mentat_core;
 extern crate mentat_query;
 
 use std::collections::BTreeSet;
+use std::ops::Sub;
 
 mod errors;
 mod types;
@@ -41,6 +42,10 @@ pub use errors::{
     Result,
 };
 
+pub use clauses::{
+    QueryInputs,
+};
+
 #[allow(dead_code)]
 pub struct AlgebraicQuery {
     default_source: SrcVar,
@@ -74,16 +79,20 @@ impl AlgebraicQuery {
     pub fn is_known_empty(&self) -> bool {
         self.cc.is_known_empty()
     }
+
+    /// Return a set of the input variables mentioned in the `:in` clause that have not yet been
+    /// bound. We do this by looking at the CC.
+    pub fn unbound_variables(&self) -> BTreeSet<Variable> {
+        self.cc.input_variables.sub(&self.cc.value_bound_variables())
+    }
 }
 
 pub fn algebrize_with_counter(schema: &Schema, parsed: FindQuery, counter: usize) -> Result<AlgebraicQuery> {
-    let alias_counter = RcCounter::with_initial(counter);
+    algebrize_with_inputs(schema, parsed, counter, QueryInputs::default())
-    let cc = clauses::ConjoiningClauses::with_alias_counter(alias_counter);
-    algebrize_with_cc(schema, parsed, cc)
 }
 
 pub fn algebrize(schema: &Schema, parsed: FindQuery) -> Result<AlgebraicQuery> {
-    algebrize_with_cc(schema, parsed, clauses::ConjoiningClauses::default())
+    algebrize_with_inputs(schema, parsed, 0, QueryInputs::default())
 }
 
 /// Take an ordering list. Any variables that aren't fixed by the query are used to produce
@@ -122,8 +131,13 @@ fn validate_and_simplify_order(cc: &ConjoiningClauses, order: Option<Vec<Order>>
     }
 }
 
-#[allow(dead_code)]
+pub fn algebrize_with_inputs(schema: &Schema,
-pub fn algebrize_with_cc(schema: &Schema, parsed: FindQuery, mut cc: ConjoiningClauses) -> Result<AlgebraicQuery> {
+                             parsed: FindQuery,
+                             counter: usize,
+                             inputs: QueryInputs) -> Result<AlgebraicQuery> {
+    let alias_counter = RcCounter::with_initial(counter);
+    let mut cc = ConjoiningClauses::with_inputs_and_alias_counter(parsed.in_vars, inputs, alias_counter);
+
     // TODO: integrate default source into pattern processing.
     // TODO: flesh out the rest of find-into-context.
     let where_clauses = parsed.where_clauses;

query-parser/Cargo.toml

@@ -5,7 +5,7 @@ workspace = ".."
 
 [dependencies]
 combine = "2.2.2"
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 matches = "0.1"
 
 [dependencies.edn]

query-parser/src/parse.rs

@@ -15,6 +15,8 @@ extern crate mentat_query;
 
 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};
 
@@ -65,6 +67,11 @@ error_chain! {
     }
 
     errors {
+        DuplicateVariableError {
+            description("duplicate variable")
+            display("duplicates in variable list")
+        }
+
         NotAVariableError(value: edn::ValueAndSpan) {
             description("not a variable")
             display("not a variable: '{}'", value)
@@ -328,6 +335,8 @@ def_parser!(Find, spec, FindSpec, {
 
 def_matches_keyword!(Find, literal_find, "find");
 
+def_matches_keyword!(Find, literal_in, "in");
+
 def_matches_keyword!(Find, literal_with, "with");
 
 def_matches_keyword!(Find, literal_where, "where");
@@ -337,11 +346,26 @@ def_matches_keyword!(Find, literal_order, "order");
 /// Express something close to a builder pattern for a `FindQuery`.
 enum FindQueryPart {
     FindSpec(FindSpec),
-    With(Vec<Variable>),
+    With(BTreeSet<Variable>),
+    In(BTreeSet<Variable>),
     WhereClauses(Vec<WhereClause>),
     Order(Vec<Order>),
 }
 
+def_parser!(Find, vars, BTreeSet<Variable>, {
+    vector().of_exactly(many(Query::variable()).and_then(|vars: Vec<Variable>| {
+            let given = vars.len();
+            let set: BTreeSet<Variable> = vars.into_iter().collect();
+            if given != set.len() {
+                // TODO: find out what the variable is!
+                let e = Box::new(Error::from_kind(ErrorKind::DuplicateVariableError));
+                Err(combine::primitives::Error::Other(e))
+            } else {
+                Ok(set)
+            }
+    }))
+});
+
 /// This is awkward, but will do for now.  We use `keyword_map()` to optionally accept vector find
 /// queries, then we use `FindQueryPart` to collect parts that have heterogeneous types; and then we
 /// construct a `FindQuery` from them.
@@ -349,8 +373,9 @@ def_parser!(Find, query, FindQuery, {
     let p_find_spec = Find::literal_find()
         .with(vector().of_exactly(Find::spec().map(FindQueryPart::FindSpec)));
 
-    let p_with_vars = Find::literal_with()
+    let p_in_vars = Find::literal_in().with(Find::vars().map(FindQueryPart::In));
-        .with(vector().of_exactly(many(Query::variable()).map(FindQueryPart::With)));
+
+    let p_with_vars = Find::literal_with().with(Find::vars().map(FindQueryPart::With));
 
     let p_where_clauses = Find::literal_where()
         .with(vector().of_exactly(Where::clauses().map(FindQueryPart::WhereClauses))).expected(":where clauses");
@@ -359,14 +384,16 @@ def_parser!(Find, query, FindQuery, {
         .with(vector().of_exactly(many1(Query::order()).map(FindQueryPart::Order)));
 
     (or(map(), keyword_map()))
-        .of_exactly(many(choice::<[&mut Parser<Input = ValueStream, Output = FindQueryPart>; 4], _>([
+        .of_exactly(many(choice::<[&mut Parser<Input = ValueStream, Output = FindQueryPart>; 5], _>([
             &mut try(p_find_spec),
+            &mut try(p_in_vars),
             &mut try(p_with_vars),
             &mut try(p_where_clauses),
             &mut try(p_order_clauses),
         ])))
         .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 where_clauses = None;
             let mut order_clauses = None;
@@ -375,6 +402,7 @@ def_parser!(Find, query, FindQuery, {
                 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::Order(x) => order_clauses = Some(x),
                 }
@@ -383,9 +411,9 @@ def_parser!(Find, query, FindQuery, {
             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(vec![]),
+                with: with_vars.unwrap_or(BTreeSet::default()),
-                in_vars: vec![],       // TODO
+                in_vars: in_vars.unwrap_or(BTreeSet::default()),
-                in_sources: vec![],    // TODO
+                in_sources: BTreeSet::default(),    // TODO
                 order: order_clauses,
                 where_clauses: where_clauses.ok_or(combine::primitives::Error::Unexpected("expected :where".into()))?,
             })
@@ -521,6 +549,33 @@ mod test {
                           vec![variable(e.clone())]);
     }
 
+    #[test]
+    fn test_repeated_vars() {
+        let e = edn::PlainSymbol::new("?e");
+        let f = edn::PlainSymbol::new("?f");
+        let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(e.clone()),
+                                            edn::Value::PlainSymbol(f.clone()),]);
+        assert_parses_to!(Find::vars, input,
+                          vec![variable(e.clone()), variable(f.clone())].into_iter().collect());
+
+        let g = edn::PlainSymbol::new("?g");
+        let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(g.clone()),
+                                            edn::Value::PlainSymbol(g.clone()),]);
+
+        let mut par = Find::vars();
+        let result = par.parse(input.with_spans().into_atom_stream())
+            .map(|x| x.0)
+            .map_err(|e| if let Some(combine::primitives::Error::Other(x)) = e.errors.into_iter().next() {
+                // Pattern matching on boxes is rocket science until Rust Nightly features hit
+                // stable.  ErrorKind isn't Clone, so convert to strings.  We could pattern match
+                // for exact comparison here.
+                x.downcast::<Error>().ok().map(|e| e.to_string())
+            } else {
+                None
+            });
+        assert_eq!(result, Err(Some("duplicates in variable list".to_string())));
+    }
+
     #[test]
     fn test_or() {
         let oj = edn::PlainSymbol::new("or");

query-projector/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 
 [dependencies.rusqlite]
 version = "0.10.1"

query-translator/src/translate.rs

@@ -14,11 +14,6 @@ use mentat_core::{
     ValueType,
 };
 
-use mentat_query::{
-    Direction,
-    Variable,
-};
-
 use mentat_query_algebrizer::{
     AlgebraicQuery,
     ColumnAlternation,

query-translator/tests/translate.rs

@@ -382,6 +382,7 @@ fn test_order_by() {
                      FROM `datoms` AS `datoms00` \
                      WHERE `datoms00`.a = 99 \
                      ORDER BY `?y` DESC");
+    assert_eq!(args, vec![]);
 
     // Unknown type.
     let input = r#"[:find ?x :with ?y :where [?x _ ?y] :order ?y ?x]"#;
@@ -390,4 +391,5 @@ fn test_order_by() {
                                      `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

@@ -33,12 +33,19 @@
 extern crate edn;
 extern crate mentat_core;
 
-use std::collections::BTreeSet;
+use std::collections::{
+    BTreeSet,
+};
+
 use std::fmt;
 use std::rc::Rc;
+
 use edn::{BigInt, OrderedFloat};
 pub use edn::{NamespacedKeyword, PlainSymbol};
-use mentat_core::TypedValue;
+
+use mentat_core::{
+    TypedValue,
+};
 
 pub type SrcVarName = String;          // Do not include the required syntactic '$'.
 
@@ -138,7 +145,7 @@ pub enum Direction {
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct Order(pub Direction, pub Variable);   // Future: Element instead of Variable?
 
-#[derive(Clone, Debug, Eq, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum SrcVar {
     DefaultSrc,
     NamedSrc(SrcVarName),
@@ -600,9 +607,9 @@ pub enum WhereClause {
 pub struct FindQuery {
     pub find_spec: FindSpec,
     pub default_source: SrcVar,
-    pub with: Vec<Variable>,
+    pub with: BTreeSet<Variable>,
-    pub in_vars: Vec<Variable>,
+    pub in_vars: BTreeSet<Variable>,
-    pub in_sources: Vec<SrcVar>,
+    pub in_sources: BTreeSet<SrcVar>,
     pub where_clauses: Vec<WhereClause>,
     pub order: Option<Vec<Order>>,
     // TODO: in_rules;

sql/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.1"
 workspace = ".."
 
 [dependencies]
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 ordered-float = "0.4.0"
 
 [dependencies.mentat_core]

src/conn.rs

@@ -10,26 +10,29 @@
 
 #![allow(dead_code)]
 
-use std::collections::HashMap;
 use std::sync::{Arc, Mutex};
 
 use rusqlite;
 
 use edn;
-use errors::*;
+
 use mentat_core::{
     Schema,
-    TypedValue,
 };
+
 use mentat_db::db;
 use mentat_db::{
     transact,
     PartitionMap,
     TxReport,
 };
+
 use mentat_tx_parser;
+
+use errors::*;
 use query::{
     q_once,
+    QueryInputs,
     QueryResults,
 };
 
@@ -112,7 +115,7 @@ impl Conn {
                      query: &str,
                      inputs: T,
                      limit: U) -> Result<QueryResults>
-        where T: Into<Option<HashMap<String, TypedValue>>>,
+        where T: Into<Option<QueryInputs>>,
               U: Into<Option<u64>>
         {
 

src/errors.rs

@@ -12,6 +12,8 @@
 
 use rusqlite;
 
+use std::collections::BTreeSet;
+
 use edn;
 use mentat_db;
 use mentat_query_algebrizer;
@@ -40,6 +42,11 @@ error_chain! {
     }
 
     errors {
+        UnboundVariables(names: BTreeSet<String>) {
+            description("unbound variables at execution time")
+            display("variables {:?} unbound at execution time", names)
+        }
+
         InvalidArgumentName(name: String) {
             description("invalid argument name")
             display("invalid argument name: '{}'", name)

src/lib.rs

@@ -54,7 +54,9 @@ pub use mentat_db::{
 pub use query::{
     NamespacedKeyword,
     PlainSymbol,
+    QueryInputs,
     QueryResults,
+    Variable,
     q_once,
 };
 

src/query.rs

@@ -8,21 +8,25 @@
 // CONDITIONS OF ANY KIND, either express or implied. See the License for the
 // specific language governing permissions and limitations under the License.
 
-use std::collections::HashMap;
-
 use rusqlite;
 use rusqlite::types::ToSql;
 
 use mentat_core::{
     Schema,
-    TypedValue,
 };
 
-use mentat_query_algebrizer::algebrize;
+use mentat_query_algebrizer::{
+    algebrize_with_inputs,
+};
+
+pub use mentat_query_algebrizer::{
+    QueryInputs,
+};
 
 pub use mentat_query::{
     NamespacedKeyword,
     PlainSymbol,
+    Variable,
 };
 
 use mentat_query_parser::{
@@ -41,31 +45,31 @@ pub use mentat_query_projector::{
     QueryResults,
 };
 
-use errors::Result;
+use errors::{
+    ErrorKind,
+    Result,
+};
 
 pub type QueryExecutionResult = Result<QueryResults>;
 
-/// Take an EDN query string, a reference to a open SQLite connection, a Mentat DB, and an optional
+/// Take an EDN query string, a reference to an open SQLite connection, a Mentat schema, and an
-/// collection of input bindings (which should be keyed by `"?varname"`), and execute the query
+/// optional collection of input bindings (which should be keyed by `"?varname"`), and execute the
-/// immediately, blocking the current thread.
+/// query immediately, blocking the current thread.
 /// Returns a structure that corresponds to the kind of input query, populated with `TypedValue`
 /// instances.
-/// The caller is responsible for ensuring that the SQLite connection is in a transaction if
+/// The caller is responsible for ensuring that the SQLite connection has an open transaction if
 /// isolation is required.
-#[allow(unused_variables)]
 pub fn q_once<'sqlite, 'schema, 'query, T, U>
 (sqlite: &'sqlite rusqlite::Connection,
  schema: &'schema Schema,
  query: &'query str,
  inputs: T,
  limit: U) -> QueryExecutionResult
-        where T: Into<Option<HashMap<String, TypedValue>>>,
+        where T: Into<Option<QueryInputs>>,
               U: Into<Option<u64>>
 {
-    // TODO: validate inputs.
-
     let parsed = parse_find_string(query)?;
-    let mut algebrized = algebrize(schema, parsed)?;
+    let mut 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.
@@ -74,6 +78,13 @@ pub fn q_once<'sqlite, 'schema, 'query, T, U>
 
     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`.
+    let unbound = algebrized.unbound_variables();
+    if !unbound.is_empty() {
+        bail!(ErrorKind::UnboundVariables(unbound.into_iter().map(|v| v.to_string()).collect()));
+    }
     let select = query_to_select(algebrized);
     let SQLQuery { sql, args } = select.query.to_sql_query()?;
 

tests/query.rs

@@ -21,11 +21,18 @@ use mentat_core::{
 
 use mentat::{
     NamespacedKeyword,
+    QueryInputs,
     QueryResults,
+    Variable,
     new_connection,
     q_once,
 };
 
+use mentat::errors::{
+    Error,
+    ErrorKind,
+};
+
 #[test]
 fn test_rel() {
     let mut c = new_connection("").expect("Couldn't open conn.");
@@ -159,3 +166,41 @@ fn test_coll() {
     println!("Coll took {}µs", start.to(end).num_microseconds().unwrap());
 }
 
+#[test]
+fn test_inputs() {
+    let mut c = new_connection("").expect("Couldn't open conn.");
+    let db = mentat_db::db::ensure_current_version(&mut c).expect("Couldn't open DB.");
+
+    // entids::DB_INSTALL_VALUE_TYPE = 5.
+    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)
+                        .expect("query to succeed");
+
+    if let QueryResults::Scalar(Some(TypedValue::Keyword(value))) = results {
+        assert_eq!(value.as_ref(), &NamespacedKeyword::new("db.install", "valueType"));
+    } else {
+        panic!("Expected scalar.");
+    }
+}
+
+/// Ensure that a query won't be run without all of its `:in` variables being bound.
+#[test]
+fn test_unbound_inputs() {
+    let mut c = new_connection("").expect("Couldn't open conn.");
+    let db = mentat_db::db::ensure_current_version(&mut c).expect("Couldn't open DB.");
+
+    // Bind the wrong var by 'mistake'.
+    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);
+
+    match results {
+        Result::Err(Error(ErrorKind::UnboundVariables(vars), _)) => {
+            assert_eq!(vars, vec!["?e".to_string()].into_iter().collect());
+        },
+        _ => panic!("Expected unbound variables."),
+    }
+}

tx-parser/Cargo.toml

@@ -5,7 +5,7 @@ workspace = ".."
 
 [dependencies]
 combine = "2.2.2"
-error-chain = "0.9.0"
+error-chain = "0.8.1"
 
 [dependencies.edn]
 path = "../edn"