marsdb_query/
value.rs

1use std::collections::BTreeMap;
2
3use marsdb_graph::{Edge, Node, PropertyValue};
4
5use crate::ast::Literal;
6
7/// One element of a `Value::Path` — a path is `node, edge, node, edge,
8/// ..., node`, alternating, as a single `Vec`, not two parallel node/edge
9/// vecs (which would create an unenforced `nodes.len() == edges.len() +
10/// 1` invariant across every place a path gets built or read).
11#[derive(Debug, Clone)]
12pub enum PathElem {
13    Node(Node),
14    Edge(Edge),
15}
16
17#[derive(Debug, Clone)]
18pub enum Value {
19    Node(Node),
20    Edge(Edge),
21    Property(PropertyValue),
22    Literal(Literal),
23    /// A list literal, `collect()` result, or a list-valued node/edge
24    /// property read back from storage (`PropertyValue::List` converts to
25    /// this, never a raw `Value::Property(PropertyValue::List(_))` — see
26    /// `executor::property_value_to_value`) — every existing list
27    /// operation (indexing, `size()`, `IN`, `UNWIND`, ...) pattern-matches
28    /// on this variant specifically, not on a property-sourced list
29    /// separately.
30    List(Vec<Value>),
31    /// A named path (`MATCH p = (a)-->(b) RETURN p`) or a `shortestPath()`
32    /// result — see `Binding::Path`'s docs (executor.rs) for how this
33    /// gets assembled during MATCH evaluation.
34    Path(Vec<PathElem>),
35    /// A map literal (`{a: 1, b: 2}`) — like `List`, a query-layer-only
36    /// concept, never persisted as a `PropertyValue` (nothing in the
37    /// grammar can construct a map literal to store as a node/edge
38    /// property directly; a `CREATE {...}` prop map's *values* are each
39    /// evaluated and stored individually as their own scalar
40    /// `PropertyValue` — see `Executor::eval_props_to_values` — a `Value::
41    /// Map` reaching there is a real error, not silently dropped). Its
42    /// other main real use is as a `date(...)`/`duration(...)`
43    /// construction function's argument, e.g. `date({year: 1984, month:
44    /// 10, day: 11})` — see `Executor::call_builtin`. `BTreeMap`, not
45    /// `HashMap` — canonical key order makes display/comparison
46    /// deterministic without a separate sort step.
47    Map(BTreeMap<String, Value>),
48    Null,
49}
marsdb_query/value.rs

marsdb_query/
value.rs
