carp-session-cbor

A deterministic-CBOR transport for Meta-Carp's warm compiler sessions (carp-session). A host process talks to one resident session over stdin/stdout. Carpaccio uses it to compile Carp from a Clojure REPL, but it has no JVM dependency.

Protocol 2

Each message is a four-byte big-endian length followed by one item in the strict CBOR subset of carp-cbor. Requests are [2, id, operation, payload], responses [2, id, success?, payload]. A failed response carries [phase, message]. On start the host loads Core from CARP_DIR and sends [2, "ready", true, 2], so a client can reject a host speaking another protocol before it sends anything.

operation	payload	success payload
ping	[]	null
quit	[]	null, then the host exits
reset	[]	null
upsert	[source] or [source, source-id]	number of invalidated definitions
upsert-input	[source, source-id]	the input's definitions: {name, kind, scheme, span}
remove	[name]	number of invalidated definitions
remove-input	[source-id]	null
ownership	[name]	{name, scheme, actions}, the ownership plan with caller spans
emit-library	[source, [root ...]]	{format: 3, c}, a C unit without main exporting only the roots

Spans are {source, start, end}, half-open byte ranges in the submitted source. emit-library compiles a transient cell and commits nothing; its roots may be defined by the cell or committed earlier.

The protocol number is independent of Session.api-version and changes only when a request or response shape does.

Build

CARP_COMPILER=../metacarp/out/carp-compiler CARP_CORE_DIR=../Carp/core \
  scripts/build.sh
scripts/smoke.sh

main.carp loads carp-session-cbor.carp, which pins carp-session and carp-cbor by commit and fetches them into the Carp library cache. CARP_SESSION_CBOR_ENTRY=dev.carp builds against adjacent ../metacarp and ../carp-cbor checkouts instead.

To embed the transport in another program, load the dependencies, then src/SessionCbor.carp, and call SessionCbor.main or SessionCbor.serve.