Struct CostBlock 

pub struct CostBlock {
    pub provenance: Option<String>,
    pub class: Option<String>,
    pub cost_fn: Option<String>,
    pub flops: Option<String>,
    pub bytes_moved: Option<String>,
    pub overhead_ns: Option<Value>,
    pub memory: Option<CostMemory>,
}

Cost block (§4.4). Coefficient EXPRESSION fields stay String — FKC’s own parser reads them later, NOT YAML. ~ (YAML null) deserializes to None.

Fields

provenance: Option<String>

declared | judge_measured — REQUIRED, both first-class (§4.4).

class: Option<String>

Coarse relative cost class bucket (§4.4).

cost_fn: Option<String>

Names a REGISTERED cost fn to PIN as the binding’s CostFn (§4.4 cost-fn trampoline, Task-F). When present the importer resolves this name through the provider’s LinkRegistry (crate::fkc::LinkRegistry::resolve_cost_fn) and registers the binding with THAT CostFn instead of the unknown_cost sentinel — so the fill_unset_cost_for_backend pass does NOT overwrite it with the op/backend default. This is the mechanism that lets a contract pin a real, shape-aware cost model (e.g. the CUDA flash_decoding static infeasibility gate cost_flash_decoding_cuda). An unresolved name is a typed crate::fkc::FkcError::UnknownCostFn import error (never a silent fallback). The name is opaque here (a String, disarming Norway); the coefficient-expression fields below stay independent. Additive (§11; no deny_unknown_fields). Serde key cost_fn.

flops: Option<String>

Symbolic FLOPs expression over shape/param symbols (§4.4).

bytes_moved: Option<String>

Symbolic bytes-moved expression (§4.4).

overhead_ns: Option<Value>

Launch overhead. May be a literal number or ~; kept as a raw scalar.

memory: Option<CostMemory>

Per-tier memory footprint (§4.4) — [consumer-ahead] beyond device_bytes.

Trait Implementations

impl Clone for CostBlock

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CostBlock

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for CostBlock

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.