Struct Database 

pub struct Database { /* private fields */ }

database: querying a database, when the host has one.

Implementations

impl Database

pub fn recorded(rows: BTreeMap<String, Vec<String>>) -> Self

A fake that answers each query from a table of canned rows, for tests.

The key is the query text exactly as the program writes it. This is a recorded answer, not a query engine: a fake that interpreted SQL would be a database this project did not write and cannot vouch for.

pub fn denied() -> Self

A host with no database, which refuses every query and says so.

The Language Card lists a denied implementation beside the real, fake, and filtered ones. Denying here rather than leaving the module out means the interface is still visible — query’s signature is in the schema — and a run that asks is told what is missing instead of being told that database is not a host module.

Trait Implementations

impl HostApi for Database

fn module_schema(&self) -> ModuleSchema

The whole of what this module declares about itself: the name Cove source uses, the capability a host must grant for it, the operations it exposes, the types it declares, and the kinds of resource it can open.

fn call(&self, op: &str, args: Vec<Value>) -> Result<Value, RuntimeError>

Invokes one operation.

fn call_resource( &self, handle: &ResourceHandle, op: &str, args: Vec<Value>, _back: &mut dyn Reentry, ) -> Result<Value, RuntimeError>

Invokes one operation on a handle this module issued.

fn call_with( &self, op: &str, args: Vec<Value>, back: &mut dyn Reentry, ) -> Result<Value, RuntimeError>

Invokes one operation.