Handle ground. (#469) r=nalexander

This commit is contained in:
Richard Newman 2017-06-09 20:20:16 -07:00
commit 8ec24f01f6
22 changed files with 1741 additions and 142 deletions

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@ -16,3 +16,7 @@ path = "../query"
# Only for tests. # Only for tests.
[dev-dependencies.mentat_query_parser] [dev-dependencies.mentat_query_parser]
path = "../query-parser" path = "../query-parser"
[dev-dependencies]
itertools = "0.5"
maplit = "0.1"

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@ -67,6 +67,7 @@ mod not;
mod pattern; mod pattern;
mod predicate; mod predicate;
mod resolve; mod resolve;
mod where_fn;
use validate::{ use validate::{
validate_not_join, validate_not_join,
@ -141,6 +142,7 @@ impl<K: Clone + Ord, V: Clone> Intersection<K> for BTreeMap<K, V> {
/// ///
/// - Ordinary pattern clauses turn into `FROM` parts and `WHERE` parts using `=`. /// - Ordinary pattern clauses turn into `FROM` parts and `WHERE` parts using `=`.
/// - Predicate clauses turn into the same, but with other functions. /// - Predicate clauses turn into the same, but with other functions.
/// - Function clauses turn into `WHERE` parts using function-specific comparisons.
/// - `not` turns into `NOT EXISTS` with `WHERE` clauses inside the subquery to /// - `not` turns into `NOT EXISTS` with `WHERE` clauses inside the subquery to
/// bind it to the outer variables, or adds simple `WHERE` clauses to the outer /// bind it to the outer variables, or adds simple `WHERE` clauses to the outer
/// clause. /// clause.
@ -228,6 +230,7 @@ impl Debug for ConjoiningClauses {
fmt.debug_struct("ConjoiningClauses") fmt.debug_struct("ConjoiningClauses")
.field("empty_because", &self.empty_because) .field("empty_because", &self.empty_because)
.field("from", &self.from) .field("from", &self.from)
.field("computed_tables", &self.computed_tables)
.field("wheres", &self.wheres) .field("wheres", &self.wheres)
.field("column_bindings", &self.column_bindings) .field("column_bindings", &self.column_bindings)
.field("input_variables", &self.input_variables) .field("input_variables", &self.input_variables)
@ -330,6 +333,12 @@ impl ConjoiningClauses {
} }
impl ConjoiningClauses { impl ConjoiningClauses {
/// Be careful with this. It'll overwrite existing bindings.
pub fn bind_value(&mut self, var: &Variable, value: TypedValue) {
self.constrain_var_to_type(var.clone(), value.value_type());
self.value_bindings.insert(var.clone(), value);
}
pub fn bound_value(&self, var: &Variable) -> Option<TypedValue> { pub fn bound_value(&self, var: &Variable) -> Option<TypedValue> {
self.value_bindings.get(var).cloned() self.value_bindings.get(var).cloned()
} }
@ -350,6 +359,10 @@ impl ConjoiningClauses {
} }
} }
pub fn known_type_set(&self, var: &Variable) -> ValueTypeSet {
self.known_types.get(var).cloned().unwrap_or(ValueTypeSet::any())
}
pub fn bind_column_to_var<C: Into<Column>>(&mut self, schema: &Schema, table: TableAlias, column: C, var: Variable) { pub fn bind_column_to_var<C: Into<Column>>(&mut self, schema: &Schema, table: TableAlias, column: C, var: Variable) {
let column = column.into(); let column = column.into();
// Do we have an external binding for this? // Do we have an external binding for this?
@ -469,14 +482,15 @@ impl ConjoiningClauses {
/// Constrains the var if there's no existing type. /// Constrains the var if there's no existing type.
/// Marks as known-empty if it's impossible for this type to apply because there's a conflicting /// Marks as known-empty if it's impossible for this type to apply because there's a conflicting
/// type already known. /// type already known.
fn constrain_var_to_type(&mut self, variable: Variable, this_type: ValueType) { fn constrain_var_to_type(&mut self, var: Variable, this_type: ValueType) {
// Is there an existing mapping for this variable? // Is there an existing mapping for this variable?
// Any known inputs have already been added to known_types, and so if they conflict we'll // Any known inputs have already been added to known_types, and so if they conflict we'll
// spot it here. // spot it here.
if let Some(existing) = self.known_types.insert(variable.clone(), ValueTypeSet::of_one(this_type)) { let this_type_set = ValueTypeSet::of_one(this_type);
if let Some(existing) = self.known_types.insert(var.clone(), this_type_set) {
// There was an existing mapping. Does this type match? // There was an existing mapping. Does this type match?
if !existing.contains(this_type) { if !existing.contains(this_type) {
self.mark_known_empty(EmptyBecause::TypeMismatch(variable, existing, this_type)); self.mark_known_empty(EmptyBecause::TypeMismatch { var, existing, desired: this_type_set });
} }
} }
} }
@ -535,10 +549,9 @@ impl ConjoiningClauses {
Entry::Occupied(mut e) => { Entry::Occupied(mut e) => {
let intersected: ValueTypeSet = types.intersection(e.get()); let intersected: ValueTypeSet = types.intersection(e.get());
if intersected.is_empty() { if intersected.is_empty() {
let mismatching_type = types.exemplar().expect("types isn't none"); let reason = EmptyBecause::TypeMismatch { var: e.key().clone(),
let reason = EmptyBecause::TypeMismatch(e.key().clone(), existing: e.get().clone(),
e.get().clone(), desired: types };
mismatching_type);
empty_because = Some(reason); empty_because = Some(reason);
} }
// Always insert, even if it's empty! // Always insert, even if it's empty!
@ -828,6 +841,9 @@ impl ConjoiningClauses {
WhereClause::Pred(p) => { WhereClause::Pred(p) => {
self.apply_predicate(schema, p) self.apply_predicate(schema, p)
}, },
WhereClause::WhereFn(f) => {
self.apply_where_fn(schema, f)
},
WhereClause::OrJoin(o) => { WhereClause::OrJoin(o) => {
validate_or_join(&o)?; validate_or_join(&o)?;
self.apply_or_join(schema, o) self.apply_or_join(schema, o)
@ -841,6 +857,18 @@ impl ConjoiningClauses {
} }
} }
pub trait PushComputed {
fn push_computed(&mut self, item: ComputedTable) -> DatomsTable;
}
impl PushComputed for Vec<ComputedTable> {
fn push_computed(&mut self, item: ComputedTable) -> DatomsTable {
let next_index = self.len();
self.push(item);
DatomsTable::Computed(next_index)
}
}
// These are helpers that tests use to build Schema instances. // These are helpers that tests use to build Schema instances.
#[cfg(test)] #[cfg(test)]
fn associate_ident(schema: &mut Schema, i: NamespacedKeyword, e: Entid) { fn associate_ident(schema: &mut Schema, i: NamespacedKeyword, e: Entid) {

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@ -32,7 +32,7 @@ impl ConjoiningClauses {
pub fn apply_not_join(&mut self, schema: &Schema, not_join: NotJoin) -> Result<()> { pub fn apply_not_join(&mut self, schema: &Schema, not_join: NotJoin) -> Result<()> {
let unified = match not_join.unify_vars { let unified = match not_join.unify_vars {
UnifyVars::Implicit => not_join.collect_mentioned_variables(), UnifyVars::Implicit => not_join.collect_mentioned_variables(),
UnifyVars::Explicit(vs) => vs.into_iter().collect(), UnifyVars::Explicit(vs) => vs,
}; };
let mut template = self.use_as_template(&unified); let mut template = self.use_as_template(&unified);

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@ -29,7 +29,10 @@ use mentat_query::{
WhereClause, WhereClause,
}; };
use clauses::ConjoiningClauses; use clauses::{
ConjoiningClauses,
PushComputed,
};
use errors::{ use errors::{
Result, Result,
@ -74,18 +77,6 @@ fn _simply_matches_value_place(left: &PatternValuePlace, right: &PatternValuePla
} }
} }
trait PushComputed {
fn push_computed(&mut self, item: ComputedTable) -> DatomsTable;
}
impl PushComputed for Vec<ComputedTable> {
fn push_computed(&mut self, item: ComputedTable) -> DatomsTable {
let next_index = self.len();
self.push(item);
DatomsTable::Computed(next_index)
}
}
pub enum DeconstructedOrJoin { pub enum DeconstructedOrJoin {
KnownSuccess, KnownSuccess,
KnownEmpty(EmptyBecause), KnownEmpty(EmptyBecause),
@ -561,7 +552,7 @@ impl ConjoiningClauses {
let (join_clauses, unify_vars, mentioned_vars) = or_join.dismember(); let (join_clauses, unify_vars, mentioned_vars) = or_join.dismember();
let projected = match unify_vars { let projected = match unify_vars {
UnifyVars::Implicit => mentioned_vars.into_iter().collect(), UnifyVars::Implicit => mentioned_vars.into_iter().collect(),
UnifyVars::Explicit(vs) => vs.into_iter().collect(), UnifyVars::Explicit(vs) => vs,
}; };
let template = self.use_as_template(&projected); let template = self.use_as_template(&projected);
@ -822,6 +813,7 @@ mod testing {
}); });
schema schema
} }
/// Test that if all the attributes in an `or` fail to resolve, the entire thing fails. /// Test that if all the attributes in an `or` fail to resolve, the entire thing fails.
#[test] #[test]
fn test_schema_based_failure() { fn test_schema_based_failure() {

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@ -801,7 +801,11 @@ mod testing {
assert!(cc.is_known_empty()); assert!(cc.is_known_empty());
assert_eq!(cc.empty_because.unwrap(), assert_eq!(cc.empty_because.unwrap(),
EmptyBecause::TypeMismatch(y.clone(), ValueTypeSet::of_one(ValueType::String), ValueType::Boolean)); EmptyBecause::TypeMismatch {
var: y.clone(),
existing: ValueTypeSet::of_one(ValueType::String),
desired: ValueTypeSet::of_one(ValueType::Boolean),
});
} }
#[test] #[test]
@ -839,7 +843,11 @@ mod testing {
assert!(cc.is_known_empty()); assert!(cc.is_known_empty());
assert_eq!(cc.empty_because.unwrap(), assert_eq!(cc.empty_because.unwrap(),
EmptyBecause::TypeMismatch(x.clone(), ValueTypeSet::of_one(ValueType::Ref), ValueType::Boolean)); EmptyBecause::TypeMismatch {
var: x.clone(),
existing: ValueTypeSet::of_one(ValueType::Ref),
desired: ValueTypeSet::of_one(ValueType::Boolean),
});
} }
#[test] #[test]

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@ -30,15 +30,13 @@ use types::{
/// Application of predicates. /// Application of predicates.
impl ConjoiningClauses { impl ConjoiningClauses {
/// There are several kinds of predicates/functions in our Datalog: /// There are several kinds of predicates in our Datalog:
/// - A limited set of binary comparison operators: < > <= >= !=. /// - A limited set of binary comparison operators: < > <= >= !=.
/// These are converted into SQLite binary comparisons and some type constraints. /// These are converted into SQLite binary comparisons and some type constraints.
/// - A set of predicates like `fulltext` and `get-else` that are translated into
/// SQL `MATCH`es or joins, yielding bindings.
/// - In the future, some predicates that are implemented via function calls in SQLite. /// - In the future, some predicates that are implemented via function calls in SQLite.
/// ///
/// At present we have implemented only the five built-in comparison binary operators. /// At present we have implemented only the five built-in comparison binary operators.
pub fn apply_predicate<'s, 'p>(&mut self, schema: &'s Schema, predicate: Predicate) -> Result<()> { 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, // 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. // 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) = NumericComparison::from_datalog_operator(predicate.operator.0.as_str()) {
@ -53,7 +51,7 @@ impl ConjoiningClauses {
/// - Ensures that the predicate functions name a known operator. /// - Ensures that the predicate functions name a known operator.
/// - Accumulates a `NumericInequality` constraint into the `wheres` list. /// - Accumulates a `NumericInequality` constraint into the `wheres` list.
#[allow(unused_variables)] #[allow(unused_variables)]
pub fn apply_numeric_predicate<'s, 'p>(&mut self, schema: &'s Schema, comparison: NumericComparison, predicate: Predicate) -> Result<()> { pub fn apply_numeric_predicate<'s>(&mut self, schema: &'s Schema, comparison: NumericComparison, predicate: Predicate) -> Result<()> {
if predicate.args.len() != 2 { if predicate.args.len() != 2 {
bail!(ErrorKind::InvalidNumberOfArguments(predicate.operator.clone(), predicate.args.len(), 2)); bail!(ErrorKind::InvalidNumberOfArguments(predicate.operator.clone(), predicate.args.len(), 2));
} }
@ -224,8 +222,10 @@ mod testing {
assert!(cc.is_known_empty()); assert!(cc.is_known_empty());
assert_eq!(cc.empty_because.unwrap(), assert_eq!(cc.empty_because.unwrap(),
EmptyBecause::TypeMismatch(y.clone(), EmptyBecause::TypeMismatch {
ValueTypeSet::of_numeric_types(), var: y.clone(),
ValueType::String)); existing: ValueTypeSet::of_numeric_types(),
desired: ValueTypeSet::of_one(ValueType::String),
});
} }
} }

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@ -50,15 +50,16 @@ impl ConjoiningClauses {
}, },
// Can't be an entid. // Can't be an entid.
EntidOrInteger(i) => Ok(QueryValue::TypedValue(TypedValue::Long(i))), EntidOrInteger(i) => Ok(QueryValue::TypedValue(TypedValue::Long(i))),
Ident(_) | IdentOrKeyword(_) |
SrcVar(_) | SrcVar(_) |
Constant(NonIntegerConstant::Boolean(_)) | Constant(NonIntegerConstant::Boolean(_)) |
Constant(NonIntegerConstant::Text(_)) | Constant(NonIntegerConstant::Text(_)) |
Constant(NonIntegerConstant::Uuid(_)) | Constant(NonIntegerConstant::Uuid(_)) |
Constant(NonIntegerConstant::Instant(_)) | // Instants are covered elsewhere. Constant(NonIntegerConstant::Instant(_)) | // Instants are covered elsewhere.
Constant(NonIntegerConstant::BigInteger(_)) => { Constant(NonIntegerConstant::BigInteger(_)) |
Vector(_) => {
self.mark_known_empty(EmptyBecause::NonNumericArgument); self.mark_known_empty(EmptyBecause::NonNumericArgument);
bail!(ErrorKind::NonNumericArgument(function.clone(), position)); bail!(ErrorKind::InvalidArgument(function.clone(), "numeric", position));
}, },
Constant(NonIntegerConstant::Float(f)) => Ok(QueryValue::TypedValue(TypedValue::Double(f))), Constant(NonIntegerConstant::Float(f)) => Ok(QueryValue::TypedValue(TypedValue::Double(f))),
} }
@ -78,7 +79,7 @@ impl ConjoiningClauses {
.ok_or_else(|| Error::from_kind(ErrorKind::UnboundVariable(var.name()))) .ok_or_else(|| Error::from_kind(ErrorKind::UnboundVariable(var.name())))
}, },
EntidOrInteger(i) => Ok(QueryValue::PrimitiveLong(i)), EntidOrInteger(i) => Ok(QueryValue::PrimitiveLong(i)),
Ident(_) => unimplemented!(), // TODO IdentOrKeyword(_) => unimplemented!(), // TODO
Constant(NonIntegerConstant::Boolean(val)) => Ok(QueryValue::TypedValue(TypedValue::Boolean(val))), Constant(NonIntegerConstant::Boolean(val)) => Ok(QueryValue::TypedValue(TypedValue::Boolean(val))),
Constant(NonIntegerConstant::Float(f)) => Ok(QueryValue::TypedValue(TypedValue::Double(f))), Constant(NonIntegerConstant::Float(f)) => Ok(QueryValue::TypedValue(TypedValue::Double(f))),
Constant(NonIntegerConstant::Text(s)) => Ok(QueryValue::TypedValue(TypedValue::typed_string(s.as_str()))), Constant(NonIntegerConstant::Text(s)) => Ok(QueryValue::TypedValue(TypedValue::typed_string(s.as_str()))),
@ -86,6 +87,7 @@ impl ConjoiningClauses {
Constant(NonIntegerConstant::Instant(u)) => Ok(QueryValue::TypedValue(TypedValue::Instant(u))), Constant(NonIntegerConstant::Instant(u)) => Ok(QueryValue::TypedValue(TypedValue::Instant(u))),
Constant(NonIntegerConstant::BigInteger(_)) => unimplemented!(), Constant(NonIntegerConstant::BigInteger(_)) => unimplemented!(),
SrcVar(_) => unimplemented!(), SrcVar(_) => unimplemented!(),
Vector(_) => unimplemented!(), // TODO
} }
} }
} }

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@ -0,0 +1,570 @@
// 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::rc::Rc;
use mentat_core::{
Schema,
SQLValueType,
TypedValue,
ValueType,
};
use mentat_query::{
Binding,
FnArg,
NonIntegerConstant,
Variable,
VariableOrPlaceholder,
WhereFn,
};
use clauses::{
ConjoiningClauses,
PushComputed,
};
use errors::{
BindingError,
ErrorKind,
Result,
};
use super::QualifiedAlias;
use types::{
ColumnConstraint,
ComputedTable,
EmptyBecause,
SourceAlias,
ValueTypeSet,
VariableColumn,
};
macro_rules! coerce_to_typed_value {
($var: ident, $val: ident, $types: expr, $type: path, $constructor: path) => { {
Ok(if !$types.contains($type) {
Impossible(EmptyBecause::TypeMismatch {
var: $var.clone(),
existing: $types,
desired: ValueTypeSet::of_one($type),
})
} else {
Val($constructor($val).into())
})
} }
}
enum ValueConversion {
Val(TypedValue),
Impossible(EmptyBecause),
}
/// Conversion of FnArgs to TypedValues.
impl ConjoiningClauses {
/// Convert the provided `FnArg` to a `TypedValue`.
/// The conversion depends on, and can fail because of:
/// - Existing known types of a variable to which this arg will be bound.
/// - Existing bindings of a variable `FnArg`.
fn typed_value_from_arg<'s>(&self, schema: &'s Schema, var: &Variable, arg: FnArg, known_types: ValueTypeSet) -> Result<ValueConversion> {
use self::ValueConversion::*;
if known_types.is_empty() {
// If this happens, it likely means the pattern has already failed!
return Ok(Impossible(EmptyBecause::TypeMismatch {
var: var.clone(),
existing: known_types,
desired: ValueTypeSet::any(),
}));
}
match arg {
// Longs are potentially ambiguous: they might be longs or entids.
FnArg::EntidOrInteger(x) => {
match (ValueType::Ref.accommodates_integer(x),
known_types.contains(ValueType::Ref),
known_types.contains(ValueType::Long)) {
(true, true, true) => {
// Ambiguous: this arg could be an entid or a long.
// We default to long.
Ok(Val(TypedValue::Long(x)))
},
(true, true, false) => {
// This can only be a ref.
Ok(Val(TypedValue::Ref(x)))
},
(_, false, true) => {
// This can only be a long.
Ok(Val(TypedValue::Long(x)))
},
(false, true, _) => {
// This isn't a valid ref, but that's the type to which this must conform!
Ok(Impossible(EmptyBecause::TypeMismatch {
var: var.clone(),
existing: known_types,
desired: ValueTypeSet::of_longs(),
}))
},
(_, false, false) => {
// Non-overlapping type sets.
Ok(Impossible(EmptyBecause::TypeMismatch {
var: var.clone(),
existing: known_types,
desired: ValueTypeSet::of_longs(),
}))
},
}
},
// If you definitely want to look up an ident, do it before running the query.
FnArg::IdentOrKeyword(x) => {
match (known_types.contains(ValueType::Ref),
known_types.contains(ValueType::Keyword)) {
(true, true) => {
// Ambiguous: this could be a keyword or an ident.
// Default to keyword.
Ok(Val(TypedValue::Keyword(Rc::new(x))))
},
(true, false) => {
// This can only be an ident. Look it up!
match schema.get_entid(&x).map(TypedValue::Ref) {
Some(e) => Ok(Val(e)),
None => Ok(Impossible(EmptyBecause::UnresolvedIdent(x.clone()))),
}
},
(false, true) => {
Ok(Val(TypedValue::Keyword(Rc::new(x))))
},
(false, false) => {
Ok(Impossible(EmptyBecause::TypeMismatch {
var: var.clone(),
existing: known_types,
desired: ValueTypeSet::of_keywords(),
}))
},
}
},
FnArg::Variable(in_var) => {
// TODO: technically you could ground an existing variable inside the query….
if !self.input_variables.contains(&in_var) {
bail!(ErrorKind::UnboundVariable((*in_var.0).clone()));
}
match self.bound_value(&in_var) {
// The type is already known if it's a bound variable….
Some(ref in_value) => Ok(Val(in_value.clone())),
None => bail!(ErrorKind::UnboundVariable((*in_var.0).clone())),
}
},
// This isn't implemented yet.
FnArg::Constant(NonIntegerConstant::BigInteger(_)) => unimplemented!(),
// These don't make sense here.
FnArg::Vector(_) |
FnArg::SrcVar(_) => bail!(ErrorKind::InvalidGroundConstant),
// These are all straightforward.
FnArg::Constant(NonIntegerConstant::Boolean(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::Boolean, TypedValue::Boolean)
},
FnArg::Constant(NonIntegerConstant::Instant(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::Instant, TypedValue::Instant)
},
FnArg::Constant(NonIntegerConstant::Uuid(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::Uuid, TypedValue::Uuid)
},
FnArg::Constant(NonIntegerConstant::Float(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::Double, TypedValue::Double)
},
FnArg::Constant(NonIntegerConstant::Text(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::String, TypedValue::String)
},
}
}
}
/// Application of `where` functions.
impl ConjoiningClauses {
/// There are several kinds of functions binding variables in our Datalog:
/// - A set of functions like `ground`, fulltext` and `get-else` that are translated into SQL
/// `VALUES`, `MATCH`, or `JOIN`, yielding bindings.
/// - In the future, some functions that are implemented via function calls in SQLite.
///
/// At present we have implemented only a limited selection of functions.
pub fn apply_where_fn<'s>(&mut self, schema: &'s Schema, where_fn: WhereFn) -> Result<()> {
// Because we'll be growing the set of built-in functions, handling each differently, and
// ultimately allowing user-specified functions, we match on the function name first.
match where_fn.operator.0.as_str() {
"ground" => self.apply_ground(schema, where_fn),
_ => bail!(ErrorKind::UnknownFunction(where_fn.operator.clone())),
}
}
fn apply_ground_place<'s>(&mut self, schema: &'s Schema, var: VariableOrPlaceholder, arg: FnArg) -> Result<()> {
match var {
VariableOrPlaceholder::Placeholder => Ok(()),
VariableOrPlaceholder::Variable(var) => self.apply_ground_var(schema, var, arg),
}
}
/// Constrain the CC to associate the given var with the given ground argument.
/// Marks known-empty on failure.
fn apply_ground_var<'s>(&mut self, schema: &'s Schema, var: Variable, arg: FnArg) -> Result<()> {
let known_types = self.known_type_set(&var);
match self.typed_value_from_arg(schema, &var, arg, known_types)? {
ValueConversion::Val(value) => self.apply_ground_value(var, value),
ValueConversion::Impossible(because) => {
self.mark_known_empty(because);
Ok(())
},
}
}
/// Marks known-empty on failure.
fn apply_ground_value(&mut self, var: Variable, value: TypedValue) -> Result<()> {
if let Some(existing) = self.bound_value(&var) {
if existing != value {
self.mark_known_empty(EmptyBecause::ConflictingBindings {
var: var.clone(),
existing: existing.clone(),
desired: value,
});
return Ok(())
}
} else {
self.bind_value(&var, value.clone());
}
let vt = value.value_type();
// Check to see whether this variable is already associated to a column.
// If so, we want to add an equality filter (or, in the future, redo the existing patterns).
if let Some(QualifiedAlias(table, column)) = self.column_bindings
.get(&var)
.and_then(|vec| vec.get(0).cloned()) {
self.constrain_column_to_constant(table, column, value);
}
// Are we also trying to figure out the type of the value when the query runs?
// If so, constrain that!
if let Some(table) = self.extracted_types.get(&var)
.map(|qa| qa.0.clone()) {
self.wheres.add_intersection(ColumnConstraint::HasType(table, vt));
}
Ok(())
}
/// Take a relation: a matrix of values which will successively bind to named variables of
/// the provided types.
/// Construct a computed table to yield this relation.
/// This function will panic if some invariants are not met.
fn collect_named_bindings<'s>(&mut self, schema: &'s Schema, names: Vec<Variable>, types: Vec<ValueType>, values: Vec<TypedValue>) {
if values.is_empty() {
return;
}
assert!(!names.is_empty());
assert_eq!(names.len(), types.len());
assert!(values.len() >= names.len());
assert_eq!(values.len() % names.len(), 0); // It's an exact multiple.
let named_values = ComputedTable::NamedValues {
names: names.clone(),
values: values,
};
let table = self.computed_tables.push_computed(named_values);
let alias = self.next_alias_for_table(table);
// Stitch the computed table into column_bindings, so we get cross-linking.
for (name, ty) in names.iter().zip(types.into_iter()) {
self.constrain_var_to_type(name.clone(), ty);
self.bind_column_to_var(schema, alias.clone(), VariableColumn::Variable(name.clone()), name.clone());
}
self.from.push(SourceAlias(table, alias));
}
pub fn apply_ground<'s>(&mut self, schema: &'s Schema, where_fn: WhereFn) -> Result<()> {
if where_fn.args.len() != 1 {
bail!(ErrorKind::InvalidNumberOfArguments(where_fn.operator.clone(), where_fn.args.len(), 1));
}
let mut args = where_fn.args.into_iter();
if where_fn.binding.is_empty() {
// The binding must introduce at least one bound variable.
bail!(ErrorKind::InvalidBinding(where_fn.operator.clone(), BindingError::NoBoundVariable));
}
if !where_fn.binding.is_valid() {
// The binding must not duplicate bound variables.
bail!(ErrorKind::InvalidBinding(where_fn.operator.clone(), BindingError::RepeatedBoundVariable));
}
// Scalar and tuple bindings are a little special: because there's only one value,
// we can immediately substitute the value as a known value in the CC, additionally
// generating a WHERE clause if columns have already been bound.
match (where_fn.binding, args.next().unwrap()) {
(Binding::BindScalar(var), constant) =>
self.apply_ground_var(schema, var, constant),
(Binding::BindTuple(places), FnArg::Vector(children)) => {
// Just the same, but we bind more than one column at a time.
if children.len() != places.len() {
// Number of arguments don't match the number of values. TODO: better error message.
bail!(ErrorKind::GroundBindingsMismatch);
}
for (place, arg) in places.into_iter().zip(children.into_iter()) {
self.apply_ground_place(schema, place, arg)? // TODO: short-circuit on impossible.
}
Ok(())
},
// Collection bindings and rel bindings are similar in that they are both
// implemented as a subquery with a projection list and a set of values.
// The difference is that BindColl has only a single variable, and its values
// are all in a single structure. That makes it substantially simpler!
(Binding::BindColl(var), FnArg::Vector(children)) => {
if children.is_empty() {
bail!(ErrorKind::InvalidGroundConstant);
}
// Turn a collection of arguments into a Vec of `TypedValue`s of the same type.
let known_types = self.known_type_set(&var);
// Check that every value has the same type.
let mut accumulated_types = ValueTypeSet::none();
let mut skip: Option<EmptyBecause> = None;
let values = children.into_iter()
.filter_map(|arg| -> Option<Result<TypedValue>> {
// We need to get conversion errors out.
// We also want to mark known-empty on impossibilty, but
// still detect serious errors.
match self.typed_value_from_arg(schema, &var, arg, known_types) {
Ok(ValueConversion::Val(tv)) => {
if accumulated_types.insert(tv.value_type()) &&
!accumulated_types.is_unit() {
// Values not all of the same type.
Some(Err(ErrorKind::InvalidGroundConstant.into()))
} else {
Some(Ok(tv))
}
},
Ok(ValueConversion::Impossible(because)) => {
// Skip this value.
skip = Some(because);
None
},
Err(e) => Some(Err(e.into())),
}
})
.collect::<Result<Vec<TypedValue>>>()?;
if values.is_empty() {
let because = skip.expect("we skipped all rows for a reason");
self.mark_known_empty(because);
return Ok(());
}
// Otherwise, we now have the values and the type.
let types = vec![accumulated_types.exemplar().unwrap()];
let names = vec![var.clone()];
self.collect_named_bindings(schema, names, types, values);
Ok(())
},
(Binding::BindRel(places), FnArg::Vector(rows)) => {
if rows.is_empty() {
bail!(ErrorKind::InvalidGroundConstant);
}
// Grab the known types to which these args must conform, and track
// the places that won't be bound in the output.
let template: Vec<Option<(Variable, ValueTypeSet)>> =
places.iter()
.map(|x| match x {
&VariableOrPlaceholder::Placeholder => None,
&VariableOrPlaceholder::Variable(ref v) => Some((v.clone(), self.known_type_set(v))),
})
.collect();
// The expected 'width' of the matrix is the number of named variables.
let full_width = places.len();
let names: Vec<Variable> = places.into_iter().filter_map(|x| x.into_var()).collect();
let expected_width = names.len();
let expected_rows = rows.len();
if expected_width == 0 {
// They can't all be placeholders.
bail!(ErrorKind::InvalidGroundConstant);
}
// Accumulate values into `matrix` and types into `a_t_f_c`.
// This representation of a rectangular matrix is more efficient than one composed
// of N separate vectors.
let mut matrix = Vec::with_capacity(expected_width * expected_rows);
let mut accumulated_types_for_columns = vec![ValueTypeSet::none(); expected_width];
// Loop so we can bail out.
let mut skipped_all: Option<EmptyBecause> = None;
for row in rows.into_iter() {
match row {
FnArg::Vector(cols) => {
// Make sure that every row is the same length.
if cols.len() != full_width {
bail!(ErrorKind::InvalidGroundConstant);
}
// TODO: don't accumulate twice.
let mut vals = Vec::with_capacity(expected_width);
let mut skip: Option<EmptyBecause> = None;
for (col, pair) in cols.into_iter().zip(template.iter()) {
// Now we have (val, Option<(name, known_types)>). Silly,
// but this is how we iter!
// Convert each item in the row.
// If any value in the row is impossible, then skip the row.
// If all rows are impossible, fail the entire CC.
if let &Some(ref pair) = pair {
match self.typed_value_from_arg(schema, &pair.0, col, pair.1)? {
ValueConversion::Val(tv) => vals.push(tv),
ValueConversion::Impossible(because) => {
// Skip this row. It cannot produce bindings.
skip = Some(because);
break;
},
}
}
}
if skip.is_some() {
// Skip this row and record why, in case we skip all.
skipped_all = skip;
continue;
}
// Accumulate the values into the matrix and the types into the type set.
for (val, acc) in vals.into_iter().zip(accumulated_types_for_columns.iter_mut()) {
let inserted = acc.insert(val.value_type());
if inserted && !acc.is_unit() {
// Heterogeneous types.
bail!(ErrorKind::InvalidGroundConstant);
}
matrix.push(val);
}
},
_ => bail!(ErrorKind::InvalidGroundConstant),
}
}
// Do we have rows? If not, the CC cannot succeed.
if matrix.is_empty() {
// We will either have bailed or will have accumulated *something* into the matrix,
// so we can safely unwrap here.
self.mark_known_empty(skipped_all.expect("we skipped for a reason"));
return Ok(());
}
// Take the single type from each set. We know there's only one: we got at least one
// type, 'cos we bailed out for zero rows, and we also bailed out each time we
// inserted a second type.
// By restricting to homogeneous columns, we greatly simplify projection. In the
// future, we could loosen this restriction, at the cost of projecting (some) value
// type tags. If and when we want to algebrize in two phases and allow for
// late-binding input variables, we'll probably be able to loosen this restriction
// with little penalty.
let types = accumulated_types_for_columns.into_iter()
.map(|x| x.exemplar().unwrap())
.collect();
self.collect_named_bindings(schema, names, types, matrix);
Ok(())
},
(_, _) => bail!(ErrorKind::InvalidGroundConstant),
}
}
}
#[cfg(test)]
mod testing {
use super::*;
use mentat_core::{
Attribute,
ValueType,
};
use mentat_query::{
Binding,
FnArg,
NamespacedKeyword,
PlainSymbol,
Variable,
};
use clauses::{
add_attribute,
associate_ident,
};
use types::{
ValueTypeSet,
};
#[test]
fn test_apply_ground() {
let vz = Variable::from_valid_name("?z");
let mut cc = ConjoiningClauses::default();
let mut schema = Schema::default();
associate_ident(&mut schema, NamespacedKeyword::new("foo", "fts"), 100);
add_attribute(&mut schema, 100, Attribute {
value_type: ValueType::String,
index: true,
fulltext: true,
..Default::default()
});
// It's awkward enough to write these expansions that we give the details for the simplest
// case only. See the tests of the translator for more extensive (albeit looser) coverage.
let op = PlainSymbol::new("ground");
cc.apply_ground(&schema, WhereFn {
operator: op,
args: vec![
FnArg::EntidOrInteger(10),
],
binding: Binding::BindScalar(vz.clone()),
}).expect("to be able to apply_ground");
assert!(!cc.is_known_empty());
// Finally, expand column bindings.
cc.expand_column_bindings();
assert!(!cc.is_known_empty());
let clauses = cc.wheres;
assert_eq!(clauses.len(), 0);
let column_bindings = cc.column_bindings;
assert_eq!(column_bindings.len(), 0); // Scalar doesn't need this.
let known_types = cc.known_types;
assert_eq!(known_types.len(), 1);
assert_eq!(known_types.get(&vz).expect("to know the type of ?z"),
&ValueTypeSet::of_one(ValueType::Long));
let value_bindings = cc.value_bindings;
assert_eq!(value_bindings.len(), 1);
assert_eq!(value_bindings.get(&vz).expect("to have a value for ?z"),
&TypedValue::Long(10)); // We default to Long instead of entid.
}
}

View file

@ -10,12 +10,20 @@
extern crate mentat_query; extern crate mentat_query;
use mentat_core::ValueType; use mentat_core::{
ValueType,
};
use self::mentat_query::{ use self::mentat_query::{
PlainSymbol, PlainSymbol,
}; };
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum BindingError {
NoBoundVariable,
RepeatedBoundVariable, // TODO: include repeated variable(s).
}
error_chain! { error_chain! {
types { types {
Error, ErrorKind, ResultExt, Result; Error, ErrorKind, ResultExt, Result;
@ -32,9 +40,9 @@ error_chain! {
display("no function named {}", name) display("no function named {}", name)
} }
InvalidNumberOfArguments(name: PlainSymbol, number: usize, expected: usize) { InvalidNumberOfArguments(function: PlainSymbol, number: usize, expected: usize) {
description("invalid number of arguments") description("invalid number of arguments")
display("invalid number of arguments to {}: expected {}, got {}.", name, expected, number) display("invalid number of arguments to {}: expected {}, got {}.", function, expected, number)
} }
UnboundVariable(name: PlainSymbol) { UnboundVariable(name: PlainSymbol) {
@ -42,9 +50,25 @@ error_chain! {
display("unbound variable: {}", name) display("unbound variable: {}", name)
} }
NonNumericArgument(function: PlainSymbol, position: usize) { InvalidBinding(function: PlainSymbol, binding_error: BindingError) {
description("invalid binding")
display("invalid binding for {}: {:?}.", function, binding_error)
}
GroundBindingsMismatch {
description("mismatched bindings in ground")
display("mismatched bindings in ground")
}
InvalidGroundConstant {
// TODO: flesh this out.
description("invalid expression in ground constant")
display("invalid expression in ground constant")
}
InvalidArgument(function: PlainSymbol, expected_type: &'static str, position: usize) {
description("invalid argument") description("invalid argument")
display("invalid argument to {}: expected numeric in position {}.", function, position) display("invalid argument to {}: expected {} in position {}.", function, expected_type, position)
} }
InvalidLimit(val: String, kind: ValueType) { InvalidLimit(val: String, kind: ValueType) {

View file

@ -13,6 +13,10 @@ extern crate enum_set;
#[macro_use] #[macro_use]
extern crate error_chain; extern crate error_chain;
#[cfg(test)]
#[macro_use]
extern crate maplit;
extern crate mentat_core; extern crate mentat_core;
extern crate mentat_query; extern crate mentat_query;
@ -42,6 +46,7 @@ use mentat_query::{
}; };
pub use errors::{ pub use errors::{
BindingError,
Error, Error,
ErrorKind, ErrorKind,
Result, Result,
@ -51,7 +56,7 @@ pub use clauses::{
QueryInputs, QueryInputs,
}; };
#[allow(dead_code)] #[derive(Debug)]
pub struct AlgebraicQuery { pub struct AlgebraicQuery {
default_source: SrcVar, default_source: SrcVar,
pub find_spec: FindSpec, pub find_spec: FindSpec,

View file

@ -53,6 +53,10 @@ pub enum ComputedTable {
type_extraction: BTreeSet<Variable>, type_extraction: BTreeSet<Variable>,
arms: Vec<::clauses::ConjoiningClauses>, arms: Vec<::clauses::ConjoiningClauses>,
}, },
NamedValues {
names: Vec<Variable>,
values: Vec<TypedValue>,
},
} }
impl DatomsTable { impl DatomsTable {
@ -228,6 +232,7 @@ impl Debug for QueryValue {
/// Represents an entry in the ORDER BY list: a variable or a variable's type tag. /// Represents an entry in the ORDER BY list: a variable or a variable's type tag.
/// (We require order vars to be projected, so we can simply use a variable here.) /// (We require order vars to be projected, so we can simply use a variable here.)
#[derive(Debug)]
pub struct OrderBy(pub Direction, pub VariableColumn); pub struct OrderBy(pub Direction, pub VariableColumn);
impl From<Order> for OrderBy { impl From<Order> for OrderBy {
@ -418,8 +423,8 @@ impl Debug for ColumnConstraint {
#[derive(PartialEq, Clone)] #[derive(PartialEq, Clone)]
pub enum EmptyBecause { pub enum EmptyBecause {
// Var, existing, desired. ConflictingBindings { var: Variable, existing: TypedValue, desired: TypedValue },
TypeMismatch(Variable, ValueTypeSet, ValueType), TypeMismatch { var: Variable, existing: ValueTypeSet, desired: ValueTypeSet },
NoValidTypes(Variable), NoValidTypes(Variable),
NonNumericArgument, NonNumericArgument,
NonStringFulltextValue, NonStringFulltextValue,
@ -435,7 +440,11 @@ impl Debug for EmptyBecause {
fn fmt(&self, f: &mut Formatter) -> ::std::fmt::Result { fn fmt(&self, f: &mut Formatter) -> ::std::fmt::Result {
use self::EmptyBecause::*; use self::EmptyBecause::*;
match self { match self {
&TypeMismatch(ref var, ref existing, ref desired) => { &ConflictingBindings { ref var, ref existing, ref desired } => {
write!(f, "Var {:?} can't be {:?} because it's already bound to {:?}",
var, desired, existing)
},
&TypeMismatch { ref var, ref existing, ref desired } => {
write!(f, "Type mismatch: {:?} can't be {:?}, because it's already {:?}", write!(f, "Type mismatch: {:?} can't be {:?}, because it's already {:?}",
var, desired, existing) var, desired, existing)
}, },
@ -496,7 +505,7 @@ impl<T: CLike + Clone> EnumSetExtensions<T> for EnumSet<T> {
} }
} }
#[derive(Clone, Debug, Eq, PartialEq)] #[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct ValueTypeSet(pub EnumSet<ValueType>); pub struct ValueTypeSet(pub EnumSet<ValueType>);
impl Default for ValueTypeSet { impl Default for ValueTypeSet {
@ -525,9 +534,27 @@ impl ValueTypeSet {
pub fn of_numeric_types() -> ValueTypeSet { pub fn of_numeric_types() -> ValueTypeSet {
ValueTypeSet(EnumSet::of_both(ValueType::Double, ValueType::Long)) ValueTypeSet(EnumSet::of_both(ValueType::Double, ValueType::Long))
} }
/// Return a set containing `Ref` and `Keyword`.
pub fn of_keywords() -> ValueTypeSet {
ValueTypeSet(EnumSet::of_both(ValueType::Ref, ValueType::Keyword))
}
/// Return a set containing `Ref` and `Long`.
pub fn of_longs() -> ValueTypeSet {
ValueTypeSet(EnumSet::of_both(ValueType::Ref, ValueType::Long))
}
} }
impl ValueTypeSet { impl ValueTypeSet {
pub fn insert(&mut self, vt: ValueType) -> bool {
self.0.insert(vt)
}
pub fn len(&self) -> usize {
self.0.len()
}
/// Returns a set containing all the types in this set and `other`. /// Returns a set containing all the types in this set and `other`.
pub fn union(&self, other: &ValueTypeSet) -> ValueTypeSet { pub fn union(&self, other: &ValueTypeSet) -> ValueTypeSet {
ValueTypeSet(self.0.union(other.0)) ValueTypeSet(self.0.union(other.0))

View file

@ -212,7 +212,7 @@ mod tests {
(and [?artist :artist/type ?type] (and [?artist :artist/type ?type]
[?type :artist/role :artist.role/parody]))]"#; [?type :artist/role :artist.role/parody]))]"#;
let parsed = parse_find_string(query).expect("expected successful parse"); let parsed = parse_find_string(query).expect("expected successful parse");
let clauses = valid_or_join(parsed, UnifyVars::Explicit(vec![Variable::from_valid_name("?artist")])); let clauses = valid_or_join(parsed, UnifyVars::Explicit(btreeset!{Variable::from_valid_name("?artist")}));
// Let's do some detailed parse checks. // Let's do some detailed parse checks.
let mut arms = clauses.into_iter(); let mut arms = clauses.into_iter();
@ -322,7 +322,7 @@ mod tests {
[?release :release/artists ?artist] [?release :release/artists ?artist]
[?release :release/year 1970])]"#; [?release :release/year 1970])]"#;
let parsed = parse_find_string(query).expect("expected successful parse"); let parsed = parse_find_string(query).expect("expected successful parse");
let clauses = valid_not_join(parsed, UnifyVars::Explicit(vec![Variable::from_valid_name("?artist")])); let clauses = valid_not_join(parsed, UnifyVars::Explicit(btreeset!{Variable::from_valid_name("?artist")}));
let release = PatternNonValuePlace::Variable(Variable::from_valid_name("?release")); let release = PatternNonValuePlace::Variable(Variable::from_valid_name("?release"));
let artist = PatternValuePlace::Variable(Variable::from_valid_name("?artist")); let artist = PatternValuePlace::Variable(Variable::from_valid_name("?artist"));

View file

@ -0,0 +1,315 @@
// 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 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,
Error,
ErrorKind,
algebrize,
};
// 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", "name"), 65);
associate_ident(&mut schema, NamespacedKeyword::new("foo", "knows"), 66);
associate_ident(&mut schema, NamespacedKeyword::new("foo", "parent"), 67);
associate_ident(&mut schema, NamespacedKeyword::new("foo", "age"), 68);
associate_ident(&mut schema, NamespacedKeyword::new("foo", "height"), 69);
add_attribute(&mut schema, 65, Attribute {
value_type: ValueType::String,
multival: false,
..Default::default()
});
add_attribute(&mut schema, 66, Attribute {
value_type: ValueType::Ref,
multival: true,
..Default::default()
});
add_attribute(&mut schema, 67, Attribute {
value_type: ValueType::String,
multival: true,
..Default::default()
});
add_attribute(&mut schema, 68, Attribute {
value_type: ValueType::Long,
multival: false,
..Default::default()
});
add_attribute(&mut schema, 69, Attribute {
value_type: ValueType::Long,
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 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_ground_doesnt_bail_for_type_conflicts() {
// We know `?x` to be a ref, but we're attempting to ground it to a Double.
// The query can return no results.
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground 9.95) ?x]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_tuple_fails_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [5 9.95]) [?x ?p]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_scalar_fails_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground true) ?p]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_coll_skips_impossible() {
// We know `?x` to be a ref, but we're attempting to ground it to a Double.
// The query can return no results.
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [5 9.95 11]) [?x ...]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.computed_tables[0], ComputedTable::NamedValues {
names: vec![Variable::from_valid_name("?x")],
values: vec![TypedValue::Ref(5), TypedValue::Ref(11)],
});
}
#[test]
fn test_ground_coll_fails_if_all_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [5.1 5.2]) [?p ...]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_rel_skips_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [[8 "foo"] [5 7] [9.95 9] [11 12]]) [[?x ?p]]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.computed_tables[0], ComputedTable::NamedValues {
names: vec![Variable::from_valid_name("?x"), Variable::from_valid_name("?p")],
values: vec![TypedValue::Ref(5), TypedValue::Ref(7), TypedValue::Ref(11), TypedValue::Ref(12)],
});
}
#[test]
fn test_ground_rel_fails_if_all_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [[11 5.1] [12 5.2]]) [[?x ?p]]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_tuple_rejects_all_placeholders() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [8 "foo" 3]) [_ _ _]]]"#;
let schema = prepopulated_schema();
bails(&schema, &q);
}
#[test]
fn test_ground_rel_rejects_all_placeholders() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [[8 "foo"]]) [[_ _]]]]"#;
let schema = prepopulated_schema();
bails(&schema, &q);
}
#[test]
fn test_ground_tuple_placeholders() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [8 "foo" 3]) [?x _ ?p]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.bound_value(&Variable::from_valid_name("?x")), Some(TypedValue::Ref(8)));
assert_eq!(cc.bound_value(&Variable::from_valid_name("?p")), Some(TypedValue::Ref(3)));
}
#[test]
fn test_ground_rel_placeholders() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [[8 "foo" 3] [5 false 7] [5 9.95 9]]) [[?x _ ?p]]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.computed_tables[0], ComputedTable::NamedValues {
names: vec![Variable::from_valid_name("?x"), Variable::from_valid_name("?p")],
values: vec![
TypedValue::Ref(8),
TypedValue::Ref(3),
TypedValue::Ref(5),
TypedValue::Ref(7),
TypedValue::Ref(5),
TypedValue::Ref(9),
],
});
}
// Nothing to do with ground, but while we're here…
#[test]
fn test_multiple_reference_type_failure() {
let q = r#"[:find ?x :where [?x :foo/age ?y] [?x :foo/knows ?y]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_tuple_infers_types() {
let q = r#"[:find ?x :where [?x :foo/age ?v] [(ground [8 10]) [?x ?v]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.bound_value(&Variable::from_valid_name("?x")), Some(TypedValue::Ref(8)));
assert_eq!(cc.bound_value(&Variable::from_valid_name("?v")), Some(TypedValue::Long(10)));
}
#[test]
fn test_ground_rel_infers_types() {
let q = r#"[:find ?x :where [?x :foo/age ?v] [(ground [[8 10]]) [[?x ?v]]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.computed_tables[0], ComputedTable::NamedValues {
names: vec![Variable::from_valid_name("?x"), Variable::from_valid_name("?v")],
values: vec![TypedValue::Ref(8), TypedValue::Long(10)],
});
}
#[test]
fn test_ground_coll_heterogeneous_types() {
let q = r#"[:find ?x :where [?x _ ?v] [(ground [false 8.5]) [?v ...]]]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::InvalidGroundConstant, _) => {
},
_ => {
panic!();
},
}
}
#[test]
fn test_ground_rel_heterogeneous_types() {
let q = r#"[:find ?x :where [?x _ ?v] [(ground [[false] [5]]) [[?v]]]]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::InvalidGroundConstant, _) => {
},
_ => {
panic!();
},
}
}
#[test]
fn test_ground_tuple_duplicate_vars() {
let q = r#"[:find ?x :where [?x :foo/age ?v] [(ground [8 10]) [?x ?x]]]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::InvalidBinding(v, e), _) => {
assert_eq!(v, PlainSymbol::new("ground"));
assert_eq!(e, BindingError::RepeatedBoundVariable);
},
_ => {
panic!();
},
}
}
#[test]
fn test_ground_rel_duplicate_vars() {
let q = r#"[:find ?x :where [?x :foo/age ?v] [(ground [[8 10]]) [[?x ?x]]]]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::InvalidBinding(v, e), _) => {
assert_eq!(v, PlainSymbol::new("ground"));
assert_eq!(e, BindingError::RepeatedBoundVariable);
},
_ => {
panic!();
},
}
}
#[test]
fn test_ground_nonexistent_variable_invalid() {
let q = r#"[:find ?x ?e :where [?e _ ?x] (not [(ground 17) ?v])]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::UnboundVariable(PlainSymbol(v)), _) => {
assert_eq!(v, "?v".to_string());
},
_ => {
panic!();
},
}
}

View file

@ -6,6 +6,7 @@ workspace = ".."
[dependencies] [dependencies]
combine = "2.3.2" combine = "2.3.2"
error-chain = "0.8.1" error-chain = "0.8.1"
maplit = "0.1"
matches = "0.1" matches = "0.1"
[dependencies.edn] [dependencies.edn]

View file

@ -10,6 +10,9 @@
#![allow(unused_imports)] #![allow(unused_imports)]
#[macro_use]
extern crate maplit;
#[macro_use] #[macro_use]
extern crate error_chain; extern crate error_chain;

View file

@ -38,6 +38,7 @@ use self::mentat_parser_utils::value_and_span::{
}; };
use self::mentat_query::{ use self::mentat_query::{
Binding,
Direction, Direction,
Element, Element,
FindQuery, FindQuery,
@ -57,7 +58,9 @@ use self::mentat_query::{
SrcVar, SrcVar,
UnifyVars, UnifyVars,
Variable, Variable,
VariableOrPlaceholder,
WhereClause, WhereClause,
WhereFn,
}; };
error_chain! { error_chain! {
@ -134,7 +137,7 @@ def_parser!(Query, predicate_fn, PredicateFn, {
}); });
def_parser!(Query, fn_arg, FnArg, { def_parser!(Query, fn_arg, FnArg, {
satisfy_map(FnArg::from_value) satisfy_map(FnArg::from_value).or(vector().of_exactly(many::<Vec<FnArg>, _>(Query::fn_arg())).map(FnArg::Vector))
}); });
def_parser!(Query, arguments, Vec<FnArg>, { def_parser!(Query, arguments, Vec<FnArg>, {
@ -197,9 +200,9 @@ def_matches_plain_symbol!(Where, not, "not");
def_matches_plain_symbol!(Where, not_join, "not-join"); def_matches_plain_symbol!(Where, not_join, "not-join");
def_parser!(Where, rule_vars, Vec<Variable>, { def_parser!(Where, rule_vars, BTreeSet<Variable>, {
seq() seq()
.of_exactly(many1(Query::variable())) .of_exactly(many1(Query::variable()).and_then(unique_vars))
}); });
def_parser!(Where, or_pattern_clause, OrWhereClause, { def_parser!(Where, or_pattern_clause, OrWhereClause, {
@ -279,6 +282,25 @@ def_parser!(Where, pred, WhereClause, {
}))) })))
}); });
/// A vector containing a parenthesized function expression and a binding.
def_parser!(Where, where_fn, WhereClause, {
// Accept either a nested list or a nested vector here:
// `[(foo ?x ?y) binding]` or `[[foo ?x ?y] binding]`
vector()
.of_exactly(
(seq().of_exactly(
(Query::predicate_fn(), Query::arguments())),
Bind::binding())
.map(|((f, args), binding)| {
WhereClause::WhereFn(
WhereFn {
operator: f.0,
args: args,
binding: binding,
})
}))
});
def_parser!(Where, pattern, WhereClause, { def_parser!(Where, pattern, WhereClause, {
vector() vector()
.of_exactly( .of_exactly(
@ -331,6 +353,7 @@ def_parser!(Where, clause, WhereClause, {
try(Where::not_clause()), try(Where::not_clause()),
try(Where::pred()), try(Where::pred()),
try(Where::where_fn()),
]) ])
}); });
@ -345,6 +368,8 @@ def_matches_plain_symbol!(Find, period, ".");
def_matches_plain_symbol!(Find, ellipsis, "..."); def_matches_plain_symbol!(Find, ellipsis, "...");
def_matches_plain_symbol!(Find, placeholder, "_");
def_parser!(Find, find_scalar, FindSpec, { def_parser!(Find, find_scalar, FindSpec, {
Query::variable() Query::variable()
.skip(Find::period()) .skip(Find::period())
@ -392,18 +417,20 @@ def_parser!(Find, spec, FindSpec, {
&mut try(Find::find_rel())]) &mut try(Find::find_rel())])
}); });
fn unique_vars<T, E>(vars: Vec<Variable>) -> std::result::Result<BTreeSet<Variable>, combine::primitives::Error<T, E>> {
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)
}
}
def_parser!(Find, vars, BTreeSet<Variable>, { def_parser!(Find, vars, BTreeSet<Variable>, {
many(Query::variable()).and_then(|vars: Vec<Variable>| { many(Query::variable()).and_then(unique_vars)
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 /// This is awkward, but will do for now. We use `keyword_map()` to optionally accept vector find
@ -446,6 +473,48 @@ def_parser!(Find, query, FindQuery, {
}) })
}); });
pub struct Bind<'a>(std::marker::PhantomData<&'a ()>);
def_parser!(Bind, bind_scalar, Binding, {
Query::variable()
.skip(eof())
.map(|var| Binding::BindScalar(var))
});
def_parser!(Bind, variable_or_placeholder, VariableOrPlaceholder, {
Query::variable().map(VariableOrPlaceholder::Variable)
.or(Find::placeholder().map(|_| VariableOrPlaceholder::Placeholder))
});
def_parser!(Bind, bind_coll, Binding, {
vector()
.of_exactly(Query::variable()
.skip(Find::ellipsis()))
.map(Binding::BindColl)
});
def_parser!(Bind, bind_rel, Binding, {
vector().of_exactly(
vector().of_exactly(
many1::<Vec<VariableOrPlaceholder>, _>(Bind::variable_or_placeholder())
.map(Binding::BindRel)))
});
def_parser!(Bind, bind_tuple, Binding, {
vector().of_exactly(
many1::<Vec<VariableOrPlaceholder>, _>(Bind::variable_or_placeholder())
.map(Binding::BindTuple))
});
def_parser!(Bind, binding, Binding, {
// Any one of the four binding types might apply, so we combine them with `choice`. Our parsers
// consume input, so we need to wrap them in `try` so that they operate independently.
choice([try(Bind::bind_scalar()),
try(Bind::bind_coll()),
try(Bind::bind_tuple()),
try(Bind::bind_rel())])
});
pub fn parse_find_string(string: &str) -> Result<FindQuery> { pub fn parse_find_string(string: &str) -> Result<FindQuery> {
let expr = edn::parse::value(string)?; let expr = edn::parse::value(string)?;
Find::query() Find::query()
@ -465,6 +534,7 @@ mod test {
use self::combine::Parser; use self::combine::Parser;
use self::edn::OrderedFloat; use self::edn::OrderedFloat;
use self::mentat_query::{ use self::mentat_query::{
Binding,
Element, Element,
FindSpec, FindSpec,
NonIntegerConstant, NonIntegerConstant,
@ -473,6 +543,7 @@ mod test {
PatternValuePlace, PatternValuePlace,
SrcVar, SrcVar,
Variable, Variable,
VariableOrPlaceholder,
}; };
use super::*; use super::*;
@ -573,7 +644,7 @@ mod test {
let e = edn::PlainSymbol::new("?e"); let e = edn::PlainSymbol::new("?e");
let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(e.clone())]); let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(e.clone())]);
assert_parses_to!(Where::rule_vars, input, assert_parses_to!(Where::rule_vars, input,
vec![variable(e.clone())]); btreeset!{variable(e.clone())});
} }
#[test] #[test]
@ -583,7 +654,7 @@ mod test {
let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(e.clone()), let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(e.clone()),
edn::Value::PlainSymbol(f.clone()),]); edn::Value::PlainSymbol(f.clone()),]);
assert_parses_to!(|| vector().of_exactly(Find::vars()), input, assert_parses_to!(|| vector().of_exactly(Find::vars()), input,
vec![variable(e.clone()), variable(f.clone())].into_iter().collect()); btreeset!{variable(e.clone()), variable(f.clone())});
let g = edn::PlainSymbol::new("?g"); let g = edn::PlainSymbol::new("?g");
let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(g.clone()), let input = edn::Value::Vector(vec![edn::Value::PlainSymbol(g.clone()),
@ -642,7 +713,7 @@ mod test {
edn::Value::PlainSymbol(v.clone())])].into_iter().collect()); edn::Value::PlainSymbol(v.clone())])].into_iter().collect());
assert_parses_to!(Where::or_join_clause, input, assert_parses_to!(Where::or_join_clause, input,
WhereClause::OrJoin( WhereClause::OrJoin(
OrJoin::new(UnifyVars::Explicit(vec![variable(e.clone())]), OrJoin::new(UnifyVars::Explicit(btreeset!{variable(e.clone())}),
vec![OrWhereClause::Clause( vec![OrWhereClause::Clause(
WhereClause::Pattern(Pattern { WhereClause::Pattern(Pattern {
source: None, source: None,
@ -685,7 +756,7 @@ mod test {
"(not-join [?e] [?e ?a ?v])", "(not-join [?e] [?e ?a ?v])",
WhereClause::NotJoin( WhereClause::NotJoin(
NotJoin { NotJoin {
unify_vars: UnifyVars::Explicit(vec![variable(e.clone())]), unify_vars: UnifyVars::Explicit(btreeset!{variable(e.clone())}),
clauses: vec![WhereClause::Pattern(Pattern { clauses: vec![WhereClause::Pattern(Pattern {
source: None, source: None,
entity: PatternNonValuePlace::Variable(variable(e)), entity: PatternNonValuePlace::Variable(variable(e)),
@ -777,4 +848,100 @@ mod test {
let mut par = Query::natural_number(); let mut par = Query::natural_number();
assert_eq!(None, par.parse(input.atom_stream()).err()); assert_eq!(None, par.parse(input.atom_stream()).err());
} }
#[test]
fn test_fn_arg_collections() {
let vx = edn::PlainSymbol::new("?x");
let vy = edn::PlainSymbol::new("?y");
let input = edn::Value::Vector(vec![edn::Value::Vector(vec![edn::Value::PlainSymbol(vx.clone()),
edn::Value::PlainSymbol(vy.clone())])]);
assert_parses_to!(|| vector().of_exactly(Query::fn_arg()),
input,
FnArg::Vector(vec![FnArg::Variable(variable(vx)),
FnArg::Variable(variable(vy)),
]));
}
#[test]
fn test_bind_scalar() {
let vx = edn::PlainSymbol::new("?x");
assert_edn_parses_to!(|| list().of_exactly(Bind::binding()),
"(?x)",
Binding::BindScalar(variable(vx)));
}
#[test]
fn test_bind_coll() {
let vx = edn::PlainSymbol::new("?x");
assert_edn_parses_to!(|| list().of_exactly(Bind::binding()),
"([?x ...])",
Binding::BindColl(variable(vx)));
}
#[test]
fn test_bind_rel() {
let vx = edn::PlainSymbol::new("?x");
let vy = edn::PlainSymbol::new("?y");
let vw = edn::PlainSymbol::new("?w");
assert_edn_parses_to!(|| list().of_exactly(Bind::binding()),
"([[?x ?y _ ?w]])",
Binding::BindRel(vec![VariableOrPlaceholder::Variable(variable(vx)),
VariableOrPlaceholder::Variable(variable(vy)),
VariableOrPlaceholder::Placeholder,
VariableOrPlaceholder::Variable(variable(vw)),
]));
}
#[test]
fn test_bind_tuple() {
let vx = edn::PlainSymbol::new("?x");
let vy = edn::PlainSymbol::new("?y");
let vw = edn::PlainSymbol::new("?w");
assert_edn_parses_to!(|| list().of_exactly(Bind::binding()),
"([?x ?y _ ?w])",
Binding::BindTuple(vec![VariableOrPlaceholder::Variable(variable(vx)),
VariableOrPlaceholder::Variable(variable(vy)),
VariableOrPlaceholder::Placeholder,
VariableOrPlaceholder::Variable(variable(vw)),
]));
}
#[test]
fn test_where_fn() {
assert_edn_parses_to!(Where::where_fn,
"[(f ?x 1) ?y]",
WhereClause::WhereFn(WhereFn {
operator: edn::PlainSymbol::new("f"),
args: vec![FnArg::Variable(Variable::from_valid_name("?x")),
FnArg::EntidOrInteger(1)],
binding: Binding::BindScalar(Variable::from_valid_name("?y")),
}));
assert_edn_parses_to!(Where::where_fn,
"[(f ?x) [?y ...]]",
WhereClause::WhereFn(WhereFn {
operator: edn::PlainSymbol::new("f"),
args: vec![FnArg::Variable(Variable::from_valid_name("?x"))],
binding: Binding::BindColl(Variable::from_valid_name("?y")),
}));
assert_edn_parses_to!(Where::where_fn,
"[(f) [?y _]]",
WhereClause::WhereFn(WhereFn {
operator: edn::PlainSymbol::new("f"),
args: vec![],
binding: Binding::BindTuple(vec![VariableOrPlaceholder::Variable(Variable::from_valid_name("?y")),
VariableOrPlaceholder::Placeholder]),
}));
assert_edn_parses_to!(Where::where_fn,
"[(f) [[_ ?y]]]",
WhereClause::WhereFn(WhereFn {
operator: edn::PlainSymbol::new("f"),
args: vec![],
binding: Binding::BindRel(vec![VariableOrPlaceholder::Placeholder,
VariableOrPlaceholder::Variable(Variable::from_valid_name("?y"))]),
}));
}
} }

View file

@ -8,6 +8,9 @@
// CONDITIONS OF ANY KIND, either express or implied. See the License for the // CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License. // specific language governing permissions and limitations under the License.
#[macro_use]
extern crate maplit;
extern crate edn; extern crate edn;
extern crate mentat_core; extern crate mentat_core;
extern crate mentat_query; extern crate mentat_query;
@ -111,7 +114,7 @@ fn can_parse_unit_or_join() {
assert_eq!(p.where_clauses, assert_eq!(p.where_clauses,
vec![ vec![
WhereClause::OrJoin(OrJoin::new( WhereClause::OrJoin(OrJoin::new(
UnifyVars::Explicit(vec![Variable::from_valid_name("?x")]), UnifyVars::Explicit(btreeset!{Variable::from_valid_name("?x")}),
vec![ vec![
OrWhereClause::Clause( OrWhereClause::Clause(
WhereClause::Pattern(Pattern { WhereClause::Pattern(Pattern {
@ -136,7 +139,7 @@ fn can_parse_simple_or_join() {
assert_eq!(p.where_clauses, assert_eq!(p.where_clauses,
vec![ vec![
WhereClause::OrJoin(OrJoin::new( WhereClause::OrJoin(OrJoin::new(
UnifyVars::Explicit(vec![Variable::from_valid_name("?x")]), UnifyVars::Explicit(btreeset!{Variable::from_valid_name("?x")}),
vec![ vec![
OrWhereClause::Clause( OrWhereClause::Clause(
WhereClause::Pattern(Pattern { WhereClause::Pattern(Pattern {

View file

@ -28,6 +28,7 @@ use rusqlite::{
use mentat_core::{ use mentat_core::{
SQLValueType, SQLValueType,
TypedValue, TypedValue,
ValueType,
}; };
use mentat_db::{ use mentat_db::{
@ -44,6 +45,7 @@ use mentat_query::{
use mentat_query_algebrizer::{ use mentat_query_algebrizer::{
AlgebraicQuery, AlgebraicQuery,
ColumnName, ColumnName,
ConjoiningClauses,
VariableColumn, VariableColumn,
}; };
@ -157,29 +159,43 @@ impl TypedIndex {
} }
} }
fn candidate_column(query: &AlgebraicQuery, var: &Variable) -> (ColumnOrExpression, Name) { fn candidate_column(cc: &ConjoiningClauses, var: &Variable) -> (ColumnOrExpression, Name) {
// Every variable should be bound by the top-level CC to at least // Every variable should be bound by the top-level CC to at least
// one column in the query. If that constraint is violated it's a // one column in the query. If that constraint is violated it's a
// bug in our code, so it's appropriate to panic here. // bug in our code, so it's appropriate to panic here.
let columns = query.cc let columns = cc.column_bindings
.column_bindings .get(var)
.get(var) .expect(format!("Every variable should have a binding, but {:?} does not", var).as_str());
.expect("Every variable has a binding");
let qa = columns[0].clone(); let qa = columns[0].clone();
let name = VariableColumn::Variable(var.clone()).column_name(); let name = VariableColumn::Variable(var.clone()).column_name();
(ColumnOrExpression::Column(qa), name) (ColumnOrExpression::Column(qa), name)
} }
fn candidate_type_column(query: &AlgebraicQuery, var: &Variable) -> (ColumnOrExpression, Name) { fn candidate_type_column(cc: &ConjoiningClauses, var: &Variable) -> (ColumnOrExpression, Name) {
let extracted_alias = query.cc let extracted_alias = cc.extracted_types
.extracted_types .get(var)
.get(var) .expect("Every variable has a known type or an extracted type");
.expect("Every variable has a known type or an extracted type");
let type_name = VariableColumn::VariableTypeTag(var.clone()).column_name(); let type_name = VariableColumn::VariableTypeTag(var.clone()).column_name();
(ColumnOrExpression::Column(extracted_alias.clone()), type_name) (ColumnOrExpression::Column(extracted_alias.clone()), type_name)
} }
/// Return the projected column -- that is, a value or SQL column and an associated name -- for a
/// given variable. Also return the type, if known.
/// Callers are expected to determine whether to project a type tag as an additional SQL column.
pub fn projected_column_for_var(var: &Variable, cc: &ConjoiningClauses) -> (ProjectedColumn, Option<ValueType>) {
if let Some(value) = cc.bound_value(&var) {
// If we already know the value, then our lives are easy.
let tag = value.value_type();
let name = VariableColumn::Variable(var.clone()).column_name();
(ProjectedColumn(ColumnOrExpression::Value(value.clone()), name), Some(tag))
} else {
// If we don't, then the CC *must* have bound the variable.
let (column, name) = candidate_column(cc, var);
(ProjectedColumn(column, name), cc.known_type(var))
}
}
/// Walk an iterator of `Element`s, collecting projector templates and columns. /// Walk an iterator of `Element`s, collecting projector templates and columns.
/// ///
/// Returns a pair: the SQL projection (which should always be a `Projection::Columns`) /// Returns a pair: the SQL projection (which should always be a `Projection::Columns`)
@ -211,10 +227,10 @@ fn project_elements<'a, I: IntoIterator<Item = &'a Element>>(
// If we're projecting this, we don't need it in :with. // If we're projecting this, we don't need it in :with.
with.remove(var); with.remove(var);
let (column, name) = candidate_column(query, var); let (projected_column, maybe_type) = projected_column_for_var(&var, &query.cc);
cols.push(ProjectedColumn(column, name)); cols.push(projected_column);
if let Some(t) = query.cc.known_type(var) { if let Some(ty) = maybe_type {
let tag = t.value_type_tag(); let tag = ty.value_type_tag();
templates.push(TypedIndex::Known(i, tag)); templates.push(TypedIndex::Known(i, tag));
i += 1; // We used one SQL column. i += 1; // We used one SQL column.
} else { } else {
@ -222,7 +238,7 @@ fn project_elements<'a, I: IntoIterator<Item = &'a Element>>(
i += 2; // We used two SQL columns. i += 2; // We used two SQL columns.
// Also project the type from the SQL query. // Also project the type from the SQL query.
let (type_column, type_name) = candidate_type_column(query, &var); let (type_column, type_name) = candidate_type_column(&query.cc, &var);
cols.push(ProjectedColumn(type_column, type_name)); cols.push(ProjectedColumn(type_column, type_name));
} }
} }
@ -233,10 +249,10 @@ fn project_elements<'a, I: IntoIterator<Item = &'a Element>>(
// We need to collect these into the SQL column list, but they don't affect projection. // We need to collect these into the SQL column list, but they don't affect projection.
// If a variable is of a non-fixed type, also project the type tag column, so we don't // If a variable is of a non-fixed type, also project the type tag column, so we don't
// accidentally unify across types when considering uniqueness! // accidentally unify across types when considering uniqueness!
let (column, name) = candidate_column(query, &var); let (column, name) = candidate_column(&query.cc, &var);
cols.push(ProjectedColumn(column, name)); cols.push(ProjectedColumn(column, name));
if query.cc.known_type(&var).is_none() { if query.cc.known_type(&var).is_none() {
let (type_column, type_name) = candidate_type_column(query, &var); let (type_column, type_name) = candidate_type_column(&query.cc, &var);
cols.push(ProjectedColumn(type_column, type_name)); cols.push(ProjectedColumn(type_column, type_name));
} }
} }

View file

@ -152,6 +152,18 @@ pub enum TableOrSubquery {
Table(SourceAlias), Table(SourceAlias),
Union(Vec<SelectQuery>, TableAlias), Union(Vec<SelectQuery>, TableAlias),
Subquery(Box<SelectQuery>), Subquery(Box<SelectQuery>),
Values(Values, TableAlias),
}
pub enum Values {
/// Like "VALUES (0, 1), (2, 3), ...".
/// The vector must be of a length that is a multiple of the given size.
Unnamed(usize, Vec<TypedValue>),
/// Like "SELECT 0 AS x, SELECT 0 AS y WHERE 0 UNION ALL VALUES (0, 1), (2, 3), ...".
/// The vector of values must be of a length that is a multiple of the length
/// of the vector of names.
Named(Vec<Variable>, Vec<TypedValue>),
} }
pub enum FromClause { pub enum FromClause {
@ -212,7 +224,13 @@ fn push_column(qb: &mut QueryBuilder, col: &Column) -> BuildQueryResult {
/// without producing an intermediate string sequence. /// without producing an intermediate string sequence.
macro_rules! interpose { macro_rules! interpose {
( $name: pat, $across: expr, $body: block, $inter: block ) => { ( $name: pat, $across: expr, $body: block, $inter: block ) => {
let mut seq = $across.iter(); interpose_iter!($name, $across.iter(), $body, $inter)
}
}
macro_rules! interpose_iter {
( $name: pat, $across: expr, $body: block, $inter: block ) => {
let mut seq = $across;
if let Some($name) = seq.next() { if let Some($name) = seq.next() {
$body; $body;
for $name in seq { for $name in seq {
@ -222,6 +240,7 @@ macro_rules! interpose {
} }
} }
} }
impl QueryFragment for ColumnOrExpression { impl QueryFragment for ColumnOrExpression {
fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult { fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult {
use self::ColumnOrExpression::*; use self::ColumnOrExpression::*;
@ -391,13 +410,60 @@ impl QueryFragment for TableOrSubquery {
out.push_identifier(table_alias.as_str()) out.push_identifier(table_alias.as_str())
}, },
&Subquery(ref subquery) => { &Subquery(ref subquery) => {
subquery.push_sql(out)?; subquery.push_sql(out)
Ok(()) },
&Values(ref values, ref table_alias) => {
// XXX: does this work for Values::Unnamed?
out.push_sql("(");
values.push_sql(out)?;
out.push_sql(") AS ");
out.push_identifier(table_alias.as_str())
}, },
} }
} }
} }
impl QueryFragment for Values {
fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult {
// There are at least 3 ways to name the columns of a VALUES table:
// 1) the columns are named "", ":1", ":2", ... -- but this is undocumented. See
// http://stackoverflow.com/a/40921724.
// 2) A CTE ("WITH" statement) can declare the shape of the table, like "WITH
// table_name(column_name, ...) AS (VALUES ...)".
// 3) We can "UNION ALL" a dummy "SELECT" statement in place.
//
// We don't want to use an undocumented SQLite quirk, and we're a little concerned that some
// SQL systems will not optimize WITH statements well. It's also convenient to have an in
// place table to query, so for now we implement option 3.
if let &Values::Named(ref names, _) = self {
out.push_sql("SELECT ");
interpose!(alias, names,
{ out.push_sql("0 AS ");
out.push_identifier(alias.as_str())? },
{ out.push_sql(", ") });
out.push_sql(" WHERE 0 UNION ALL ");
}
let values = match self {
&Values::Named(ref names, ref values) => values.chunks(names.len()),
&Values::Unnamed(ref size, ref values) => values.chunks(*size),
};
out.push_sql("VALUES ");
interpose_iter!(outer, values,
{ out.push_sql("(");
interpose!(inner, outer,
{ out.push_typed_value(inner)? },
{ out.push_sql(", ") });
out.push_sql(")");
},
{ out.push_sql(", ") });
Ok(())
}
}
impl QueryFragment for FromClause { impl QueryFragment for FromClause {
fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult { fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult {
use self::FromClause::*; use self::FromClause::*;
@ -494,7 +560,7 @@ mod tests {
DatomsTable, DatomsTable,
}; };
fn build_constraint(c: Constraint) -> String { fn build(c: &QueryFragment) -> String {
let mut builder = SQLiteQueryBuilder::new(); let mut builder = SQLiteQueryBuilder::new();
c.push_sql(&mut builder) c.push_sql(&mut builder)
.map(|_| builder.finish()) .map(|_| builder.finish())
@ -524,9 +590,9 @@ mod tests {
], ],
}; };
assert_eq!("`datoms01`.v IN ()", build_constraint(none)); assert_eq!("`datoms01`.v IN ()", build(&none));
assert_eq!("`datoms01`.v IN (123)", build_constraint(one)); assert_eq!("`datoms01`.v IN (123)", build(&one));
assert_eq!("`datoms01`.v IN (123, 456, 789)", build_constraint(three)); assert_eq!("`datoms01`.v IN (123, 456, 789)", build(&three));
} }
#[test] #[test]
@ -552,7 +618,37 @@ mod tests {
// Two sets of parens: the outermost AND only has one child, // Two sets of parens: the outermost AND only has one child,
// but still contributes parens. // but still contributes parens.
assert_eq!("((123 = 456 AND 789 = 246))", build_constraint(c)); assert_eq!("((123 = 456 AND 789 = 246))", build(&c));
}
#[test]
fn test_unnamed_values() {
let build = |len, values| build(&Values::Unnamed(len, values));
assert_eq!(build(1, vec![TypedValue::Long(1)]),
"VALUES (1)");
assert_eq!(build(2, vec![TypedValue::Boolean(false), TypedValue::Long(1)]),
"VALUES (0, 1)");
assert_eq!(build(2, vec![TypedValue::Boolean(false), TypedValue::Long(1),
TypedValue::Boolean(true), TypedValue::Long(2)]),
"VALUES (0, 1), (1, 2)");
}
#[test]
fn test_named_values() {
let build = |names: Vec<_>, values| build(&Values::Named(names.into_iter().map(Variable::from_valid_name).collect(), values));
assert_eq!(build(vec!["?a"], vec![TypedValue::Long(1)]),
"SELECT 0 AS `?a` WHERE 0 UNION ALL VALUES (1)");
assert_eq!(build(vec!["?a", "?b"], vec![TypedValue::Boolean(false), TypedValue::Long(1)]),
"SELECT 0 AS `?a`, 0 AS `?b` WHERE 0 UNION ALL VALUES (0, 1)");
assert_eq!(build(vec!["?a", "?b"],
vec![TypedValue::Boolean(false), TypedValue::Long(1),
TypedValue::Boolean(true), TypedValue::Long(2)]),
"SELECT 0 AS `?a`, 0 AS `?b` WHERE 0 UNION ALL VALUES (0, 1), (1, 2)");
} }
#[test] #[test]

View file

@ -38,6 +38,7 @@ use mentat_query_algebrizer::{
use mentat_query_projector::{ use mentat_query_projector::{
CombinedProjection, CombinedProjection,
Projector, Projector,
projected_column_for_var,
query_projection, query_projection,
}; };
@ -51,6 +52,7 @@ use mentat_query_sql::{
SelectQuery, SelectQuery,
TableList, TableList,
TableOrSubquery, TableOrSubquery,
Values,
}; };
trait ToConstraint { trait ToConstraint {
@ -201,33 +203,33 @@ fn table_for_computed(computed: ComputedTable, alias: TableAlias) -> TableOrSubq
// project it as the variable name. // project it as the variable name.
// E.g., SELECT datoms03.v AS `?x`. // E.g., SELECT datoms03.v AS `?x`.
for var in projection.iter() { for var in projection.iter() {
let col = cc.column_bindings.get(&var).unwrap()[0].clone(); let (projected_column, maybe_type) = projected_column_for_var(var, &cc);
let proj = ProjectedColumn(ColumnOrExpression::Column(col), var.to_string()); columns.push(projected_column);
columns.push(proj);
}
// Similarly, project type tags if they're not known conclusively in the // Similarly, project type tags if they're not known conclusively in the
// outer query. // outer query.
for var in type_extraction.iter() { // Assumption: we'll never need to project a tag without projecting the value of a variable.
let expression = if type_extraction.contains(var) {
if let Some(known) = cc.known_type(var) { let expression =
// If we know the type for sure, just project the constant. if let Some(ty) = maybe_type {
// SELECT datoms03.v AS `?x`, 10 AS `?x_value_type_tag` // If we know the type for sure, just project the constant.
ColumnOrExpression::Integer(known.value_type_tag()) // SELECT datoms03.v AS `?x`, 10 AS `?x_value_type_tag`
} else { ColumnOrExpression::Integer(ty.value_type_tag())
// Otherwise, we'll have an established type binding! This'll be } else {
// either a datoms table or, recursively, a subquery. Project // Otherwise, we'll have an established type binding! This'll be
// this: // either a datoms table or, recursively, a subquery. Project
// SELECT datoms03.v AS `?x`, // this:
// datoms03.value_type_tag AS `?x_value_type_tag` // SELECT datoms03.v AS `?x`,
let extract = cc.extracted_types // datoms03.value_type_tag AS `?x_value_type_tag`
.get(var) let extract = cc.extracted_types
.expect("Expected variable to have a known type or an extracted type"); .get(var)
ColumnOrExpression::Column(extract.clone()) .expect("Expected variable to have a known type or an extracted type");
}; ColumnOrExpression::Column(extract.clone())
let type_column = VariableColumn::VariableTypeTag(var.clone()); };
let proj = ProjectedColumn(expression, type_column.column_name()); let type_column = VariableColumn::VariableTypeTag(var.clone());
columns.push(proj); let proj = ProjectedColumn(expression, type_column.column_name());
columns.push(proj);
}
} }
// Each arm simply turns into a subquery. // Each arm simply turns into a subquery.
@ -239,7 +241,13 @@ fn table_for_computed(computed: ComputedTable, alias: TableAlias) -> TableOrSubq
}, },
ComputedTable::Subquery(subquery) => { ComputedTable::Subquery(subquery) => {
TableOrSubquery::Subquery(Box::new(cc_to_exists(subquery))) TableOrSubquery::Subquery(Box::new(cc_to_exists(subquery)))
} },
ComputedTable::NamedValues {
names, values,
} => {
// We assume column homogeneity, so we won't have any type tag columns.
TableOrSubquery::Values(Values::Named(names, values), alias)
},
} }
} }

View file

@ -550,3 +550,180 @@ fn test_complex_nested_or_join_type_projection() {
LIMIT 1"); LIMIT 1");
assert_eq!(args, vec![]); assert_eq!(args, vec![]);
} }
#[test]
fn test_ground_scalar() {
let schema = prepopulated_schema();
// Verify that we accept inline constants.
let query = r#"[:find ?x . :where [(ground "yyy") ?x]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT $v0 AS `?x` LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "yyy")]);
// Verify that we accept bound input constants.
let query = r#"[:find ?x . :in ?v :where [(ground ?v) ?x]]"#;
let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?v"), TypedValue::String(Rc::new("aaa".into())))]);
let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
assert_eq!(sql, "SELECT $v0 AS `?x` LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "aaa"),]);
}
#[test]
fn test_ground_tuple() {
let schema = prepopulated_schema();
// Verify that we accept inline constants.
let query = r#"[:find ?x ?y :where [(ground [1 "yyy"]) [?x ?y]]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT 1 AS `?x`, $v0 AS `?y`");
assert_eq!(args, vec![make_arg("$v0", "yyy")]);
// Verify that we accept bound input constants.
let query = r#"[:find [?x ?y] :in ?u ?v :where [(ground [?u ?v]) [?x ?y]]]"#;
let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?u"), TypedValue::Long(2)),
(Variable::from_valid_name("?v"), TypedValue::String(Rc::new("aaa".into()))),]);
let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
// TODO: treat 2 as an input variable that could be bound late, rather than eagerly binding it.
assert_eq!(sql, "SELECT 2 AS `?x`, $v0 AS `?y` LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "aaa"),]);
}
#[test]
fn test_ground_coll() {
let schema = prepopulated_schema();
// Verify that we accept inline constants.
let query = r#"[:find ?x :where [(ground ["xxx" "yyy"]) [?x ...]]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x` FROM \
(SELECT 0 AS `?x` WHERE 0 UNION ALL VALUES ($v0), ($v1)) AS `c00`");
assert_eq!(args, vec![make_arg("$v0", "xxx"),
make_arg("$v1", "yyy")]);
// Verify that we accept bound input constants.
let query = r#"[:find ?x :in ?u ?v :where [(ground [?u ?v]) [?x ...]]]"#;
let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?u"), TypedValue::Long(2)),
(Variable::from_valid_name("?v"), TypedValue::Long(3)),]);
let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
// TODO: treat 2 and 3 as input variables that could be bound late, rather than eagerly binding.
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x` FROM \
(SELECT 0 AS `?x` WHERE 0 UNION ALL VALUES (2), (3)) AS `c00`");
assert_eq!(args, vec![]);
}
#[test]
fn test_ground_rel() {
let schema = prepopulated_schema();
// Verify that we accept inline constants.
let query = r#"[:find ?x ?y :where [(ground [[1 "xxx"] [2 "yyy"]]) [[?x ?y]]]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x`, `c00`.`?y` AS `?y` FROM \
(SELECT 0 AS `?x`, 0 AS `?y` WHERE 0 UNION ALL VALUES (1, $v0), (2, $v1)) AS `c00`");
assert_eq!(args, vec![make_arg("$v0", "xxx"),
make_arg("$v1", "yyy")]);
// Verify that we accept bound input constants.
let query = r#"[:find ?x ?y :in ?u ?v :where [(ground [[?u 1] [?v 2]]) [[?x ?y]]]]"#;
let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?u"), TypedValue::Long(3)),
(Variable::from_valid_name("?v"), TypedValue::Long(4)),]);
let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
// TODO: treat 3 and 4 as input variables that could be bound late, rather than eagerly binding.
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x`, `c00`.`?y` AS `?y` FROM \
(SELECT 0 AS `?x`, 0 AS `?y` WHERE 0 UNION ALL VALUES (3, 1), (4, 2)) AS `c00`");
assert_eq!(args, vec![]);
}
#[test]
fn test_compound_with_ground() {
let schema = prepopulated_schema();
// Verify that we can use the resulting CCs as children in compound CCs.
let query = r#"[:find ?x :where (or [(ground "yyy") ?x]
[(ground "zzz") ?x])]"#;
let SQLQuery { sql, args } = translate(&schema, query);
// This is confusing because the computed tables (like `c00`) are numbered sequentially in each
// arm of the `or` rather than numbered globally. But SQLite scopes the names correctly, so it
// works. In the future, we might number the computed tables globally to make this more clear.
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x` FROM (\
SELECT $v0 AS `?x` UNION \
SELECT $v1 AS `?x`) AS `c00`");
assert_eq!(args, vec![make_arg("$v0", "yyy"),
make_arg("$v1", "zzz"),]);
// Verify that we can use ground to constrain the bindings produced by earlier clauses.
let query = r#"[:find ?x . :where [_ :foo/bar ?x] [(ground "yyy") ?x]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT $v0 AS `?x` FROM `datoms` AS `datoms00` \
WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "yyy")]);
// Verify that we can further constrain the bindings produced by our clause.
let query = r#"[:find ?x . :where [(ground "yyy") ?x] [_ :foo/bar ?x]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT $v0 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_unbound_attribute_with_ground_entity() {
let query = r#"[:find ?x ?v :where [?x _ ?v] (not [(ground 17) ?x])]"#;
let schema = prepopulated_schema();
let SQLQuery { sql, .. } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT `all_datoms00`.e AS `?x`, \
`all_datoms00`.v AS `?v`, \
`all_datoms00`.value_type_tag AS `?v_value_type_tag` \
FROM `all_datoms` AS `all_datoms00` \
WHERE NOT EXISTS (SELECT 1 WHERE `all_datoms00`.e = 17)");
}
#[test]
fn test_unbound_attribute_with_ground() {
let query = r#"[:find ?x ?v :where [?x _ ?v] (not [(ground 17) ?v])]"#;
let schema = prepopulated_schema();
let SQLQuery { sql, .. } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT `all_datoms00`.e AS `?x`, \
`all_datoms00`.v AS `?v`, \
`all_datoms00`.value_type_tag AS `?v_value_type_tag` \
FROM `all_datoms` AS `all_datoms00` \
WHERE NOT EXISTS (SELECT 1 WHERE `all_datoms00`.v = 17 AND \
`all_datoms00`.value_type_tag = 5)");
}
#[test]
fn test_not_with_ground() {
let mut schema = prepopulated_schema();
associate_ident(&mut schema, NamespacedKeyword::new("db", "valueType"), 7);
associate_ident(&mut schema, NamespacedKeyword::new("db.type", "ref"), 23);
associate_ident(&mut schema, NamespacedKeyword::new("db.type", "bool"), 28);
associate_ident(&mut schema, NamespacedKeyword::new("db.type", "instant"), 29);
add_attribute(&mut schema, 7, Attribute {
value_type: ValueType::Ref,
multival: false,
..Default::default()
});
// Scalar.
// TODO: this kind of simple `not` should be implemented without the subquery. #476.
let query = r#"[:find ?x :where [?x :db/valueType ?v] (not [(ground :db.type/instant) ?v])]"#;
let SQLQuery { sql, .. } = translate(&schema, query);
assert_eq!(sql,
"SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 7 AND NOT \
EXISTS (SELECT 1 WHERE `datoms00`.v = 29)");
// Coll.
// TODO: we can generate better SQL for this, too. #476.
let query = r#"[:find ?x :where [?x :db/valueType ?v] (not [(ground [:db.type/bool :db.type/instant]) [?v ...]])]"#;
let SQLQuery { sql, .. } = translate(&schema, query);
assert_eq!(sql,
"SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` \
WHERE `datoms00`.a = 7 AND NOT EXISTS \
(SELECT 1 FROM (SELECT 0 AS `?v` WHERE 0 UNION ALL VALUES (28), (29)) AS `c00` \
WHERE `datoms00`.v = `c00`.`?v`)");
}

View file

@ -35,6 +35,7 @@ extern crate mentat_core;
use std::collections::{ use std::collections::{
BTreeSet, BTreeSet,
HashSet,
}; };
use std::fmt; use std::fmt;
@ -59,7 +60,7 @@ use mentat_core::{
pub type SrcVarName = String; // Do not include the required syntactic '$'. pub type SrcVarName = String; // Do not include the required syntactic '$'.
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord)] #[derive(Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct Variable(pub Rc<PlainSymbol>); pub struct Variable(pub Rc<PlainSymbol>);
impl Variable { impl Variable {
@ -174,7 +175,11 @@ impl FromValue<SrcVar> for SrcVar {
impl SrcVar { impl SrcVar {
pub fn from_symbol(sym: &PlainSymbol) -> Option<SrcVar> { pub fn from_symbol(sym: &PlainSymbol) -> Option<SrcVar> {
if sym.is_src_symbol() { if sym.is_src_symbol() {
Some(SrcVar::NamedSrc(sym.plain_name().to_string())) if sym.0 == "$" {
Some(SrcVar::DefaultSrc)
} else {
Some(SrcVar::NamedSrc(sym.plain_name().to_string()))
}
} else { } else {
None None
} }
@ -210,22 +215,47 @@ pub enum FnArg {
Variable(Variable), Variable(Variable),
SrcVar(SrcVar), SrcVar(SrcVar),
EntidOrInteger(i64), EntidOrInteger(i64),
Ident(NamespacedKeyword), IdentOrKeyword(NamespacedKeyword),
Constant(NonIntegerConstant), Constant(NonIntegerConstant),
// The collection values representable in EDN. There's no advantage to destructuring up front,
// since consumers will need to handle arbitrarily nested EDN themselves anyway.
Vector(Vec<FnArg>),
} }
impl FromValue<FnArg> for FnArg { impl FromValue<FnArg> for FnArg {
fn from_value(v: &edn::ValueAndSpan) -> Option<FnArg> { fn from_value(v: &edn::ValueAndSpan) -> Option<FnArg> {
// TODO: support SrcVars. use edn::SpannedValue::*;
Variable::from_value(v) match v.inner {
.and_then(|v| Some(FnArg::Variable(v))) Integer(x) =>
.or_else(|| { Some(FnArg::EntidOrInteger(x)),
println!("from_value {}", v.inner); PlainSymbol(ref x) if x.is_src_symbol() =>
match v.inner { SrcVar::from_symbol(x).map(FnArg::SrcVar),
edn::SpannedValue::Integer(i) => Some(FnArg::EntidOrInteger(i)), PlainSymbol(ref x) if x.is_var_symbol() =>
edn::SpannedValue::Float(f) => Some(FnArg::Constant(NonIntegerConstant::Float(f))), Variable::from_symbol(x).map(FnArg::Variable),
_ => unimplemented!(), PlainSymbol(_) => None,
}}) NamespacedKeyword(ref x) =>
Some(FnArg::IdentOrKeyword(x.clone())),
Instant(x) =>
Some(FnArg::Constant(NonIntegerConstant::Instant(x))),
Uuid(x) =>
Some(FnArg::Constant(NonIntegerConstant::Uuid(x))),
Boolean(x) =>
Some(FnArg::Constant(NonIntegerConstant::Boolean(x))),
Float(x) =>
Some(FnArg::Constant(NonIntegerConstant::Float(x))),
BigInteger(ref x) =>
Some(FnArg::Constant(NonIntegerConstant::BigInteger(x.clone()))),
Text(ref x) =>
// TODO: intern strings. #398.
Some(FnArg::Constant(NonIntegerConstant::Text(Rc::new(x.clone())))),
Nil |
NamespacedSymbol(_) |
Keyword(_) |
Vector(_) |
List(_) |
Set(_) |
Map(_) => None,
}
} }
} }
@ -505,6 +535,94 @@ impl FindSpec {
} }
} }
// Datomic accepts variable or placeholder. DataScript accepts recursive bindings. Mentat sticks
// to the non-recursive form Datomic accepts, which is much simpler to process.
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub enum VariableOrPlaceholder {
Placeholder,
Variable(Variable),
}
impl VariableOrPlaceholder {
pub fn into_var(self) -> Option<Variable> {
match self {
VariableOrPlaceholder::Placeholder => None,
VariableOrPlaceholder::Variable(var) => Some(var),
}
}
pub fn var(&self) -> Option<&Variable> {
match self {
&VariableOrPlaceholder::Placeholder => None,
&VariableOrPlaceholder::Variable(ref var) => Some(var),
}
}
}
#[derive(Clone,Debug,Eq,PartialEq)]
pub enum Binding {
BindScalar(Variable),
BindColl(Variable),
BindRel(Vec<VariableOrPlaceholder>),
BindTuple(Vec<VariableOrPlaceholder>),
}
impl Binding {
/// Return each variable or `None`, in order.
pub fn variables(&self) -> Vec<Option<Variable>> {
match self {
&Binding::BindScalar(ref var) | &Binding::BindColl(ref var) => vec![Some(var.clone())],
&Binding::BindRel(ref vars) | &Binding::BindTuple(ref vars) => vars.iter().map(|x| x.var().cloned()).collect(),
}
}
/// Return `true` if no variables are bound, i.e., all binding entries are placeholders.
pub fn is_empty(&self) -> bool {
match self {
&Binding::BindScalar(_) | &Binding::BindColl(_) => false,
&Binding::BindRel(ref vars) | &Binding::BindTuple(ref vars) => vars.iter().all(|x| x.var().is_none()),
}
}
/// Return `true` if no variable is bound twice, i.e., each binding entry is either a
/// placeholder or unique.
///
/// ```
/// extern crate mentat_query;
/// use std::rc::Rc;
///
/// let v = mentat_query::Variable::from_valid_name("?foo");
/// let vv = mentat_query::VariableOrPlaceholder::Variable(v);
/// let p = mentat_query::VariableOrPlaceholder::Placeholder;
///
/// let e = mentat_query::Binding::BindTuple(vec![p.clone()]);
/// let b = mentat_query::Binding::BindTuple(vec![p.clone(), vv.clone()]);
/// let d = mentat_query::Binding::BindTuple(vec![vv.clone(), p, vv]);
/// assert!(b.is_valid()); // One var, one placeholder: OK.
/// assert!(!e.is_valid()); // Empty: not OK.
/// assert!(!d.is_valid()); // Duplicate var: not OK.
/// ```
pub fn is_valid(&self) -> bool {
match self {
&Binding::BindScalar(_) | &Binding::BindColl(_) => true,
&Binding::BindRel(ref vars) | &Binding::BindTuple(ref vars) => {
let mut acc = HashSet::<Variable>::new();
for var in vars {
if let &VariableOrPlaceholder::Variable(ref var) = var {
if !acc.insert(var.clone()) {
// It's invalid if there was an equal var already present in the set --
// i.e., we have a duplicate var.
return false;
}
}
}
// We're not valid if every place is a placeholder!
!acc.is_empty()
}
}
}
}
// Note that the "implicit blank" rule applies. // Note that the "implicit blank" rule applies.
// A pattern with a reversed attribute — :foo/_bar — is reversed // A pattern with a reversed attribute — :foo/_bar — is reversed
// at the point of parsing. These `Pattern` instances only represent // at the point of parsing. These `Pattern` instances only represent
@ -560,6 +678,13 @@ pub struct Predicate {
pub args: Vec<FnArg>, pub args: Vec<FnArg>,
} }
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct WhereFn {
pub operator: PlainSymbol,
pub args: Vec<FnArg>,
pub binding: Binding,
}
#[derive(Clone, Debug, Eq, PartialEq)] #[derive(Clone, Debug, Eq, PartialEq)]
pub enum UnifyVars { pub enum UnifyVars {
/// `Implicit` means the variables in an `or` or `not` are derived from the enclosed pattern. /// `Implicit` means the variables in an `or` or `not` are derived from the enclosed pattern.
@ -586,7 +711,7 @@ pub enum UnifyVars {
/// Only the named variables will be unified with the enclosing query. /// Only the named variables will be unified with the enclosing query.
/// ///
/// Every 'arm' in an `or-join` must mention the entire set of explicit vars. /// Every 'arm' in an `or-join` must mention the entire set of explicit vars.
Explicit(Vec<Variable>), Explicit(BTreeSet<Variable>),
} }
impl WhereClause { impl WhereClause {
@ -635,7 +760,7 @@ pub enum WhereClause {
NotJoin(NotJoin), NotJoin(NotJoin),
OrJoin(OrJoin), OrJoin(OrJoin),
Pred(Predicate), Pred(Predicate),
WhereFn, WhereFn(WhereFn),
RuleExpr, RuleExpr,
Pattern(Pattern), Pattern(Pattern),
} }
@ -701,7 +826,7 @@ impl ContainsVariables for WhereClause {
&Pred(ref p) => p.accumulate_mentioned_variables(acc), &Pred(ref p) => p.accumulate_mentioned_variables(acc),
&Pattern(ref p) => p.accumulate_mentioned_variables(acc), &Pattern(ref p) => p.accumulate_mentioned_variables(acc),
&NotJoin(ref n) => n.accumulate_mentioned_variables(acc), &NotJoin(ref n) => n.accumulate_mentioned_variables(acc),
&WhereFn => (), &WhereFn(ref f) => f.accumulate_mentioned_variables(acc),
&RuleExpr => (), &RuleExpr => (),
} }
} }
@ -765,6 +890,34 @@ impl ContainsVariables for Predicate {
} }
} }
impl ContainsVariables for Binding {
fn accumulate_mentioned_variables(&self, acc: &mut BTreeSet<Variable>) {
match self {
&Binding::BindScalar(ref v) | &Binding::BindColl(ref v) => {
acc_ref(acc, v)
},
&Binding::BindRel(ref vs) | &Binding::BindTuple(ref vs) => {
for v in vs {
if let &VariableOrPlaceholder::Variable(ref v) = v {
acc_ref(acc, v);
}
}
},
}
}
}
impl ContainsVariables for WhereFn {
fn accumulate_mentioned_variables(&self, acc: &mut BTreeSet<Variable>) {
for arg in &self.args {
if let &FnArg::Variable(ref v) = arg {
acc_ref(acc, v)
}
}
self.binding.accumulate_mentioned_variables(acc);
}
}
fn acc_ref<T: Clone + Ord>(acc: &mut BTreeSet<T>, v: &T) { fn acc_ref<T: Clone + Ord>(acc: &mut BTreeSet<T>, v: &T) {
// Roll on, reference entries! // Roll on, reference entries!
if !acc.contains(v) { if !acc.contains(v) {