mentat/parser-utils/src
Nick Alexander 4b874deae1 Lookup refs, nested vector values, map notation. Fixes #180, fixes #183, fixes #284. (#382) r=rnewman
* Pre: Fix error in parser macros.

* Pre: Make test unwrapping more verbose.

* Pre: Make lookup refs be (lookup-ref a v) in the entity position.

This has the advantage of being explicit in all situations and
unambiguous at parse-time.  This choice agrees with the Clojure
implementation but not with Datomic.  Datomic treats [a v] as a lookup
ref, is ambiguous at parse-time, and is disambiguated in ways I do not
understand at transaction time.  We mooted making lookup refs [[a v]]
and outlawing nested value vectors in transactions, but after
implementing that approach I decided it was better to handle lookup
refs at parse time and therefore outlawing nested value vectors is not
necessary.

* Handle lookup refs in the entity and value columns. Fixes #183.

* Pre 0a: Use a stack instead of into_iter.

* Pre 0b: Dedent.

* Pre 0c: Handle `e` after `v`.

This allows to use the original `e` while handling `v`.

* Explode value lists for :db.cardinality/many attributes. Fixes #284.

* Parse and accept map notation. Fixes #180.

* Pre: Modernize add() and retract() into one add_or_retract().

* Pre: Add is_collection and is_atom to edn::Value.

* Pre: Differentiate atoms from lookup-refs in value position.

Initially, I expected to accept arbitrary edn::Value instances in the
value position, and to differentiate in the transactor.  However, the
implementation quickly became a two-stage parser, since we always
wanted to parse the resulting value position into some other known
thing using the tx-parser.  To save calls into the parser and to allow
the parser to move forward with a smaller API surface, I push as much
of this parsing as possible into the initial parse.

* Pre: Modernize entities().

* Pre: Quote edn::Value::Text in Display.

* Review comment: Add and use edn::Value::into_atom.

* Review comment: Use skip(eof()) throughout.

* Review comment: VecDeque instead of Vec.

* Review comment: Part 0: Rename TempId to TempIdHandle.

* Review comment: Part 1: Differentiate internal and external tempids.

This breaks an abstraction boundary by pushing the Internal/External
split up to the Entity level in tx/ and tx-parser/.  This just makes
it easier to explode Entity map notation instances into Entity
instances, taking an existing External tempid :db/id or generating a
new Internal tempid as appropriate.  To do this without breaking the
abstraction boundary would require adding flexibility to the
transaction processor: we'd need to be able to turn Entity instances
into some internal enum and handle the two cases independently.  It
wouldn't be too hard, but this reduces the combinatorial type
explosion.
2017-03-27 16:30:04 -07:00
..
lib.rs Lookup refs, nested vector values, map notation. Fixes #180, fixes #183, fixes #284. (#382) r=rnewman 2017-03-27 16:30:04 -07:00