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Allow :db/id to mentioned as a pull attribute.

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This commit is contained in:
Richard Newman 2018-05-07 21:39:24 -07:00
parent 4665eaa4dd
commit a114bda46b
3 changed files with 49 additions and 9 deletions
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5
query-pull/src/errors.rs
View file

@ -22,6 +22,11 @@ error_chain! {
description("unnamed attribute")
display("attribute {:?} has no name", id)
}
RepeatedDbId {
description(":db/id repeated")
display(":db/id repeated")
}
}
links {

26
query-pull/src/lib.rs
View file

@ -79,12 +79,14 @@ use std::iter::{
};
use mentat_core::{
Binding,
Cloned,
Entid,
HasSchema,
NamespacedKeyword,
Schema,
StructuredMap,
TypedValue,
ValueRc,
};
@ -143,6 +145,7 @@ pub struct Puller {
// The range is the set of aliases to use in the output.
attributes: BTreeMap<Entid, ValueRc<NamespacedKeyword>>,
attribute_spec: cache::AttributeSpec,
db_id_alias: Option<ValueRc<NamespacedKeyword>>,
}
impl Puller {
@ -166,6 +169,9 @@ impl Puller {
let mut names: BTreeMap<Entid, ValueRc<NamespacedKeyword>> = Default::default();
let mut attrs: BTreeSet<Entid> = Default::default();
let db_id = ::std::rc::Rc::new(NamespacedKeyword::new("db", "id"));
let mut db_id_alias = None;
for attr in attributes.iter() {
match attr {
&PullAttributeSpec::Wildcard => {
@ -183,6 +189,14 @@ impl Puller {
let alias = alias.as_ref()
.map(|ref r| r.to_value_rc());
match attribute {
// Handle :db/id.
&PullConcreteAttribute::Ident(ref i) if i.as_ref() == db_id.as_ref() => {
// We only allow :db/id once.
if db_id_alias.is_some() {
bail!(ErrorKind::RepeatedDbId);
}
db_id_alias = Some(alias.unwrap_or_else(|| db_id.to_value_rc()));
},
&PullConcreteAttribute::Ident(ref i) => {
if let Some(entid) = schema.get_entid(i) {
let name = alias.unwrap_or_else(|| i.to_value_rc());
@ -203,6 +217,7 @@ impl Puller {
Ok(Puller {
attributes: names,
attribute_spec: cache::AttributeSpec::specified(&attrs, schema),
db_id_alias,
})
}
@ -234,6 +249,17 @@ impl Puller {
// TODO: should we walk `e` then `a`, or `a` then `e`? Possibly the right answer
// is just to collect differently!
let mut maps = BTreeMap::new();
// Collect :db/id if requested.
if let Some(ref alias) = self.db_id_alias {
for e in entities.iter() {
let mut r = maps.entry(*e)
.or_insert(ValueRc::new(StructuredMap::default()));
let mut m = ValueRc::get_mut(r).unwrap();
m.insert(alias.clone(), Binding::Scalar(TypedValue::Ref(*e)));
}
}
for (name, cache) in self.attributes.iter().filter_map(|(a, name)|
caches.forward_attribute_cache_for_attribute(schema, *a)
.map(|cache| (name.clone(), cache))) {

27
tests/pull.rs
View file

@ -116,7 +116,9 @@ fn test_simple_pull() {
assert_eq!(pulled, expected);
// Now test pull inside the query itself.
let query = r#"[:find ?hood (pull ?district [[:district/name :as :district/district] :district/region])
let query = r#"[:find ?hood (pull ?district [:db/id
[:district/name :as :district/district]
:district/region])
:where
(or [?hood :neighborhood/name "Beacon Hill"]
[?hood :neighborhood/name "Capitol Hill"])
@ -127,22 +129,24 @@ fn test_simple_pull() {
.into_rel_result()
.expect("results");
let beacon_district: Vec<(NamespacedKeyword, TypedValue)> = vec![
let beacon_district_pull: Vec<(NamespacedKeyword, TypedValue)> = vec![
(kw!(:db/id), TypedValue::Ref(beacon_district)),
(kw!(:district/district), "Greater Duwamish".into()),
(kw!(:district/region), schema.get_entid(&NamespacedKeyword::new("region", "se")).unwrap().into())
];
let beacon_district: StructuredMap = beacon_district.into();
let capitol_district: Vec<(NamespacedKeyword, TypedValue)> = vec![
let beacon_district_pull: StructuredMap = beacon_district_pull.into();
let capitol_district_pull: Vec<(NamespacedKeyword, TypedValue)> = vec![
(kw!(:db/id), TypedValue::Ref(capitol_district)),
(kw!(:district/district), "East".into()),
(kw!(:district/region), schema.get_entid(&NamespacedKeyword::new("region", "e")).unwrap().into())
];
let capitol_district: StructuredMap = capitol_district.into();
let capitol_district_pull: StructuredMap = capitol_district_pull.into();
let expected = RelResult {
width: 2,
values: vec![
TypedValue::Ref(capitol).into(), capitol_district.into(),
TypedValue::Ref(beacon).into(), beacon_district.into(),
TypedValue::Ref(capitol).into(), capitol_district_pull.into(),
TypedValue::Ref(beacon).into(), beacon_district_pull.into(),
].into(),
};
assert_eq!(results, expected.clone());
@ -158,14 +162,19 @@ fn test_simple_pull() {
// Execute a scalar query where the body is constant.
// TODO: we shouldn't require `:where`; that makes this non-constant!
let query = r#"[:find (pull ?hood [:neighborhood/name]) . :in ?hood
let query = r#"[:find (pull ?hood [[:db/id :as :neighborhood/id]
:neighborhood/name]) .
:in ?hood
:where [?hood :neighborhood/district _]]"#;
let result = reader.q_once(query, QueryInputs::with_value_sequence(vec![(var!(?hood), TypedValue::Ref(beacon))]))
.into_scalar_result()
.expect("success")
.expect("result");
let expected: StructuredMap = vec![(kw!(:neighborhood/name), TypedValue::from("Beacon Hill"))].into();
let expected: StructuredMap = vec![
(kw!(:neighborhood/name), TypedValue::from("Beacon Hill")),
(kw!(:neighborhood/id), TypedValue::Ref(beacon)),
].into();
assert_eq!(result, expected.into());
// Collect the names and regions of all districts.