Checked contract types#

check_contract returns parcel_core::check::CheckedContract. These types contain checked definitions; executable plans are created by compilation.

`CheckedContract`#

Field	Type	Meaning
`name`	`String`	Contract name.
`version`	`u32`	Version number.
`contract_hash`	`String`	Canonical document hash.
`owner`	`Option<String>`	Resolved owner.
`binding`	`Binding`	Resolved data location.
`residency`	`crate::Residency`	Resolved placement requirements.
`exposed`	`Vec<ExposedColumn>`	Checked output columns.
`rules`	`Vec<CheckedRule>`	Typed rule definitions.
`functions`	`BTreeSet<FunctionPin>`	Required function identities.
`other`	`OtherTypes`	Declared extension types.
`enrichers`	`Vec<(String, CheckedExpr)>`	Custom row field names paired with checked calculations.
`producers`	`Vec<Producer>`	Custom dataset calculations.

`CheckedExpr` and `ExposedColumn`#

Type	Public fields
`CheckedExpr`	`source: String` contains the original expression; `expr: TExpr` is its typed expression tree.
`ExposedColumn`	`name: String`, `type_name: String` as written in the contract, and `data_type: DataType` as an Arrow type.
`OtherTypes` (in `parcel_core::checker`)	`row`, `ctx`, and `dataset`: each `BTreeMap<String, Type>` containing declared custom fields.

`CheckedRule`#

pub enum CheckedRule {
    Decide { id: String, expr: CheckedExpr },
    Admit { id: String, expr: CheckedExpr },
    Assert { id: String, expr: CheckedExpr, on_fail: AssertOnFail },
    Transform { id: String, column: String, expr: CheckedExpr },
    Guarantee { id: String, expr: CheckedExpr, on_fail: GuaranteeOnFail },
    Shape { id: String, shape: ShapeOp, unless: Option<CheckedExpr> },
}

id identifies the rule, expr contains its checked condition or calculation, column identifies a transformed output, and on_fail records the failure action. shape contains the checked shape parameters; unless can exempt a caller.

impl CheckedRule {
    pub fn id(&self) -> &str;
    pub fn exprs(&self) -> Vec<&CheckedExpr>;
}

id borrows the identifier. exprs borrows the rule’s expressions; for a shape it returns its unless expression if present.

Dataset producers#

Producer has public fields field: String, ty: Type, and kind: ProducerKind.

ProducerKind is Constant(parcel_core::ir::Lit) or Aggregate { func: Aggregate, arg: Option<CheckedExpr> }. Aggregate variants are Count, Sum, Avg, Min, Max, CountDistinct, and Median.

`Residency`#

parcel_core::Residency contains jurisdictions: BTreeSet<String> and approved_output_may_leave: bool.

Method	Meaning
`permits(&self, jurisdiction: &str) -> bool`	Tests whether a recognized jurisdiction code is in the allowed set.
`validate(&self) -> Result<(), String>`	Rejects an empty set or unknown codes.

The accepted codes are the implementation’s ISO two-letter country codes and EU. default() creates an empty set and sets output release to false.

Checked contract types#