# std/rpc

Typed RPC as a library, built on generator imports. A procedure is an exported function of a procedure module with at most one parameter and both ends serializable (the `Api` contract plus `rpcWhyNotSerializable`); anything else fails the load at the generator call.

- Directory forms: `rpc(dir)` mounts every module under an api directory at a path derived from the module path and the export name; `client(dir)` and `clientInProcess(dir)` emit the calling side.
- Single-module forms: `rpcServer`, `rpcClient` and `rpcInProcess`.

Inspect a generated module with `vyrn emit-gen <file>`, the derived table with `vyrn routes <file>`.

## validateContract

`fn`, at line 94.

```vyrn
gen fn validateContract(iface: ModuleInterface) -> String
```

The first objection to `iface` as a procedure module, or "": the `Api` contract, then serializability. A `gen fn`, because `contractOf` has no runtime lowering. Exported for `std/http`'s REST projection, which publishes the same procedures under the same rule.

## rpcServer

`fn`, at line 246.

```vyrn
gen fn rpcServer(contract: String) -> String
```

Emits a module that imports the contract's procedures and exposes `rpcHandle(req: Request) -> Option<Response>`.

## rpcClient

`fn`, at line 339.

```vyrn
gen fn rpcClient(contract: String) -> String
```

Emits the client: the contract's type declarations, one stub per procedure over one `vyrnRpcCall` extern, and one completion per procedure. The caller passes the callback inline: `createPaste(req, |res| match res { .. })`.

## rpcInProcess

`fn`, at line 390.

```vyrn
gen fn rpcInProcess(contract: String) -> String
```

Emits the deterministic test and SSR flavor: a stub per procedure under the same name the wire client exposes, running the real procedure synchronously.

## rpc

`fn`, at line 868.

```vyrn
gen fn rpc(dir: String) -> String
```

Mounts every procedure module under `dir` at its derived path. Two procedures deriving one path fail the build naming both.

## client

`fn`, at line 987.

```vyrn
gen fn client(dir: String) -> String
```

The calling side of an api directory. It reads interfaces, re-emits types and never imports an api module, so no procedure body reaches a client bundle.

## clientInProcess

`fn`, at line 1052.

```vyrn
gen fn clientInProcess(dir: String) -> String
```

`client(dir)` with direct dispatch. A separate generator, because a generator cannot see its importer's audience; the stubs share names, so a composition root swaps one import line.

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From https://vyrn-lang.github.io/docs/std/rpc.html — generated by `site/export.vyrn` from the Vyrn repository.