writeonce

A declarative full-stack programming language. You write .wo files; the runtime compiles them into a binary that owns the database, serves REST, and pushes live subscriptions — no external database, no external web server, no frontend framework.

Think Go + Postgres + net/http + Phoenix LiveView, folded into one language and one binary.

persistant database

• reads and writes database to RAM, persist data to postgres SQL.
• The entire database lives in RAM; every committed write is mirrored to PostgreSQL as a backup — asynchronously, behind the runtime's own WAL, never in the read or ack path. Set WO_PG=postgres://user@host:5432/db and every type's rows appear as a Postgres table (named by its @table(name: ...) annotation) that you can query with plain psql. Plan and phases: docs/plan/16-postgres-mirror.md; try it: just pricing-pg-demo.

Quickstart

git clone https://github.com/shoneyJ/writeonce
cd writeonce
cargo run --bin wo -- run docs/examples/blog     # serve the sample blog on :8080
curl http://127.0.0.1:8080/api/articles          # it's a real REST API now

See reference/rest/blog.rest for a preconfigured HTTP-request file that drives the whole sample — open it in VS Code (with the REST Client extension) or JetBrains and click "Send Request" on each block.

What this repository contains

Path	What it is
crates/rt/	The new .wo language runtime — lexer, type-DSL parser, in-memory engine, axum REST server. Produces the wo binary.
crates/{ql,value,engine,txn,db,wal,sub,http,gen,policy,logic,service,ui,app}/	14 empty placeholder crates scaffolded for Phases 2–6. Real code extracts from rt/ as each phase activates.
docs/runtime/wo-language.md	Start here. The language overview: toolchain, hello-world, stdlib, client model.
docs/runtime/database.md	The 7-phase engineering series that drives the runtime's design.
docs/examples/blog/	Sample .wo project: blog with articles, authors, tags, comments. ~200 lines.
docs/examples/ecommerce/	Sample .wo project: storefront + live order-ops table + cross-paradigm checkout. ~300 lines.
prototypes/wo-db/	C++ prototype of the query-layer engine (SQL + Cypher + document paths, RETURNING aliases, LIVE stub). ~2k lines, smoke tests pass. Reference implementation the Rust port follows.
reference/rest/	.rest files (VS Code REST Client / JetBrains HTTP format) for manually testing the running prototype.
reference/crates/	The v1 writeonce blog — 13 Rust crates implementing the original .seg + sidecar-index storage engine and .htmlx templating. Preserved as a nested workspace; see reference/README.md.

Current stage

The runtime is under active development. Each stage lands as an independently shippable cut:

Stage	What works	Status
1	wo run <dir> discovers every .wo file under a directory	✅ shipped
2	Type-DSL parser, in-memory engine, REST CRUD (list / get / create / update / delete) generated from service rest blocks, JSON bodies with auto-id, default-value seeding, partial-update PATCH	✅ shipped — cargo run -- run docs/examples/blog
3	LIVE subscriptions over WebSocket, delta frames on commit, me / session layer	pending
4+	Transactional fns (fn checkout in txn snapshot), row-level policies, type-attached triggers, ##ui SSR, WAL durability, codegen	see docs/runtime/database.md

cargo test --lib at the root runs 14 unit tests covering the lexer, parser, compiler, and engine. Stage-3 endpoints respond 501 Not Implemented until they land.

Build & test

cargo build                                         # builds all 15 crates (only `rt` has real code)
cargo test --lib                                    # 14 unit tests

cargo run --bin wo -- run docs/examples/blog       # serve the blog sample
cargo run --bin wo -- run docs/examples/ecommerce  # serve the ecommerce sample

# Override the listen address
WO_LISTEN=127.0.0.1:9000 cargo run --bin wo -- run docs/examples/blog

The v1 codebase (reference)

The original writeonce blog engine — 13 crates, flat-file .seg storage, sidecar indexes, .htmlx templates, hand-rolled epoll event loop — moved to reference/crates/ when the new runtime was scaffolded. It's a nested Cargo workspace:

cd reference/crates
cargo build                   # all 13 v1 crates still compile
cargo test                    # 12 unit tests, 1 ignored integration test

V1 crates keep the wo- prefix (wo-seg, wo-store, …). The new runtime crates dropped it (ql, value, engine, …). docs/runtime/database/07-wo-seg-migration.md is the phased coexistence plan for replacing v1 with the new runtime — abstract behind a trait, dual-write, cut over, decommission.

License & status

Work in progress. Nothing here is stable. Read the language overview in docs/runtime/wo-language.md if you want to know the shape; read the phase docs if you want to see the engineering plan; look in docs/examples/ if you want to see what the end product feels like.