Commit graph

7 commits

Author SHA1 Message Date
Nick Alexander
2cb7d441dc Part 2: Make it easier to match tuple results.
Right now, we write code like
```rust
match q_once(q, inputs)?.into_tuple()? {
    Some(vs) => match (vs.len(), vs.get(0), vs.get(1)) {
        (2, &Some(Binding::Scalar(TypedValue::Long(a))), &Some(Binding::Scalar(TypedValue::Instant(ref b)))) => Some((a, b.clone())),
        _ => panic!(),
    },
    None => None,
}
```
to length-check tuples coming out of the database.  It can also lead
to a lot of cloning because references are the easiest thing to hand.

This commit allows to write code like
```rust
match q_once(q, inputs)?.into_tuple()? {
    Some((Binding::Scalar(TypedValue::Long(a)), Binding::Scalar(TypedValue::Instant(b)))) => Some((a, b)),
    Some(_) => panic!(),
    None => None,
}
```
which is generally much easier to reason about.
2018-07-05 16:45:42 -07:00
Nick Alexander
8725bad18c Pre: Fix error printing rusqlite::Error. 2018-06-30 14:58:23 -07:00
Nick Alexander
b2249f189d Convert query-projector/ to ProjectorError. 2018-06-27 15:05:43 -07:00
Grisha Kruglov
c075434f84 Convert query_projector/ to failure. 2018-06-20 14:42:10 -07:00
Richard Newman
e21156a754
Implement simple pull expressions (#638) r=nalexander
* Refactor AttributeCache populator code for use from pull.

* Pre: add to_value_rc to Cloned.

* Pre: add From<StructuredMap> for Binding.

* Pre: clarify Store::open_empty.

* Pre: StructuredMap cleanup.

* Pre: clean up a doc test.

* Split projector crate. Pass schema to projector.

* CLI support for printing bindings.

* Add and use ConjoiningClauses::derive_types_from_find_spec.

* Define pull types.

* Implement pull on top of the attribute cache layer.

* Add pull support to the projector.

* Parse pull expressions.

* Add simple pull support to connection objects.

* Tests for pull.

* Compile with Rust 1.25.

The only choice involved in this commit is that of replacing the
anonymous lifetime '_ with a named lifetime for the cache; since we're
accepting a Known, which includes the cache in question, I think it's
clear that we expect the function to apply to any given cache
lifetime.

* Review comments.

* Bail on unnamed attribute.

* Make assert_parse_failure_contains safe to use.

* Rework query parser to report better errors for pull.

* Test for mixed wildcard and simple attribute.
2018-05-04 12:56:00 -07:00
Richard Newman
1509d16c3e
Fix (the ?foo) (#633) r=nalexander
Don't group by ?var when processing (the ?var).

This PR also finishes error generation in the projector.
2018-04-10 11:58:58 -07:00
Richard Newman
909b2a8be5 Refactoring: split up the projector crate. No other code changes. 2018-04-09 10:26:09 -07:00