CIDER-style nREPL: jack-in, per-project connections, completion, eldoc, doc, M-.

.github/workflows/test.yml

@@ -37,9 +37,11 @@ jobs:
         run: |
           go build -C "$GITHUB_WORKSPACE/../let-go" -o "$GITHUB_WORKSPACE/../lg" .
 
+      # lg goes on PATH too: the jack-in tests start a real `lg -n` server
+      # the same way the editor does.
       - name: Run test suite
         run: |
-          "$GITHUB_WORKSPACE/../lg" test/run.lg
+          PATH="$GITHUB_WORKSPACE/..:$PATH" "$GITHUB_WORKSPACE/../lg" test/run.lg
 
       # Full AOT native build (build lg, lower legmacs.*, bundle, go build) -- the
       # same path release.yml ships. Guards against a build break landing on main.

.let-go-version

@@ -5,4 +5,4 @@
 # May be a commit SHA (reproducible) or a branch name like `main` (tracks tip).
 # legmacs's AOT build needs the gogen lowering + scripts/lg-compile tooling,
 # which live on main; bump this SHA when you want newer let-go fixes.
-a6657612002bd70b277617368985639992d1c11b
+36d57e3693075f9e63e4aff49b220331ff3fea12

CLAUDE.md

@@ -42,9 +42,12 @@ lg test/run.lg
 Run a single test namespace (faster iteration than the full suite):
 
 ```sh
-lg -e "(require '[test :refer [run-tests]] '[test.region-test]) (run-tests)"
+lg -e "(require '[test :refer [run-tests]] '[test.region-test]) (run-tests 'test.region-test)"
 ```
 
+(`run-tests` with no arguments tests only `*ns*`, like Clojure's, so name
+the namespace -- a bare `(run-tests)` reports 0 tests and success.)
+
 There's no separate build/lint step — `lg` interprets `.lg` source directly.
 `test/run.lg` is a hand-maintained list of every test namespace; adding a
 new `test/*_test.lg` file means adding its namespace to that `:require`
@@ -254,11 +257,46 @@ form at point, highlights it, snapshots its source, and evaluates it through
 `bufs/spawn-task`. Completion verifies that the source span is unchanged
 before replacing it. Ordinary values use `pr-str`; functions that need
 source-aware application return `replacement-result` with a registered
-result-kind handler. This async/result seam is also the intended boundary
-for a future nREPL backend: `register-eval-backend!` installs an async-safe
-`(fn [request] -> value)` and `use-eval-backend!` selects it. Requests carry
-the source plus filename/column/namespace context; backends never touch live
-buffer state.
+result-kind handler. The same seam carries every other eval command: all four build one
+request (`:op` `:eval`/`:load`, `:source`, `:forms`, `:state`, `:backend`,
+and filename/directory/line/column/namespace `:context`) and hand it to
+the buffer's backend. Which backend is `letgo/eval-backend-for`: the
+first registered resolver that claims the buffer, else the global
+`current-eval-backend` -- resolvers run every frame (the lighter), so they
+must stay string checks, no filesystem. With `:in-process`,
+`C-x C-e`/`C-j`/`C-c C-e` still eval synchronously on the main thread (so
+editor-scripting forms take effect before the next frame); any other
+backend makes them `spawn-task` jobs too. Remote backends return
+`printed-result` (text the server printed, plus captured output) since
+the value never existed in this VM. Completion
+(`legmacs.modes.letgo-complete`, TAB/M-TAB) routes the same way through a
+per-backend `completers` registry, and so do eldoc, doc and `M-.`
+(`legmacs.modes.letgo-lookup`, a `lookups` registry of `(fn [request] ->
+info-map)`). let-go-mode's single `:after-command` now runs
+paren-matching and then `letgo/after-command-hooks` (eldoc is one), each
+in a try so a failing hook can't break editing. eldoc runs every key, so
+it scans only back to the enclosing top-level form (a `(` in column 0)
+and reads the ns form from the buffer's first 80 lines; remote answers
+come from a short-TTL cache, fetched by a quiet `spawn-task`. Goto uses
+a `:visit` buffer-command (show buffer by `:id`/`:filename`/`:name`, or
+open `:state`, at `:row`/`:col`) and a shared `:xref-stack` for `M-,`.
+
+`legmacs.nrepl` is the nREPL backend: one connection per project root
+(buffers with a `:filename` under it resolve to it; fileless buffers like
+`*scratch*` never do), one blocking bencode round trip per request,
+serialized by a channel-token lock, inside the job's future -- so no
+long-lived reader goroutine exists for `loop-wait` to keep polling.
+`legmacs.jack-in` starts servers from data launch configs. let-go
+interop can't reach `cmd.Process`, so a server runs under `sh -c` that
+writes a pid file, redirects output to a log (an unread pipe would fill
+and block it) and `exec`s the command; the editor holds its stdin pipe
+open (`lg -n` exits on EOF) and stops it with SIGTERM + closing stdin.
+Liveness is `ps -o stat=`, not `kill -0`: an exited child is a zombie
+until Waited, and `kill -0` says a zombie is alive. `bufs/add-exit-hook!`
+hooks run after `main.lg` restores the terminal; both namespaces use it
+so no server outlives the editor. The editor picks the port
+(`os/free-port`) rather than reading `.nrepl-port`, which Babashka
+doesn't write for port 0. Backends never touch live buffer state.
 
 `legmacs.vibe/vibe` uses that protocol rather than owning a special key
 command. Under the dynamic `letgo/*eval-replace-context*` it derives its

README.md

@@ -38,6 +38,13 @@ started:
   form (or select several), evaluate it without blocking the editor, and
   replace the source with its result; the active form is highlighted while
   it runs
+- CIDER-style nREPL: `C-c M-j` starts and connects the project's server
+  -- lgx, Clojure CLI (with cider-nrepl), Babashka, or plain `lg` -- and
+  that project's buffers then evaluate and complete there; the server
+  stops when you disconnect or quit
+- symbol completion on `TAB`/`M-TAB`, eldoc arglists as you type, doc
+  lookup (`C-c C-d d`) and goto-definition (`M-.`/`M-,`, into jars for
+  Clojure libraries), all from the editor's own VM or the connected server
 - a dedicated `*repl*` buffer (`C-c C-z`), for when you want an actual
   running transcript instead of building one by hand with `C-j`
 - `(vibe "...")`: write what you want where you want it, then use the same

build/go.mod

@@ -1,15 +1,24 @@
 module legmacs/build
 
-go 1.26
+go 1.27
 
 require github.com/nooga/let-go v0.0.0-00010101000000-000000000000
 
 require (
-	github.com/klauspost/cpuid/v2 v2.2.10 // indirect
+	github.com/ebitengine/gomobile v0.0.0-20260820040257-d11f821a26a6 // indirect
+	github.com/ebitengine/hideconsole v1.0.0 // indirect
+	github.com/ebitengine/purego v0.11.0 // indirect
+	github.com/go-gl/gl v0.0.0-20260331235117-4566fea9a276 // indirect
+	github.com/go-gl/glfw/v3.3/glfw v0.0.0-20260823155953-d41da22a9587 // indirect
+	github.com/hajimehoshi/ebiten/v2 v2.10.2 // indirect
+	github.com/klauspost/cpuid/v2 v2.4.0 // indirect
 	github.com/zeebo/bencode v1.0.0 // indirect
 	github.com/zeebo/xxh3 v1.1.0 // indirect
-	golang.org/x/sys v0.44.0 // indirect
-	golang.org/x/term v0.41.0 // indirect
+	golang.org/x/image v0.46.0 // indirect
+	golang.org/x/sync v0.23.0 // indirect
+	golang.org/x/sys v0.48.0 // indirect
+	golang.org/x/term v0.46.0 // indirect
+	golang.org/x/text v0.42.0 // indirect
 )
 
 replace github.com/nooga/let-go => ../../let-go

build/go.sum

@@ -1,20 +1,34 @@
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/klauspost/cpuid/v2 v2.2.10 h1:tBs3QSyvjDyFTq3uoc/9xFpCuOsJQFNPiAhYdw2skhE=
-github.com/klauspost/cpuid/v2 v2.2.10/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/ebitengine/gomobile v0.0.0-20260820040257-d11f821a26a6 h1:Tnc3YtzxhgsvNdNrER9wWkGJbyjOwyUuzjUY5rZK72k=
+github.com/ebitengine/gomobile v0.0.0-20260820040257-d11f821a26a6/go.mod h1:gwnFEwdzWZpNehgwkeK4756Ez58f58bXz6bgEAq+xqk=
+github.com/ebitengine/hideconsole v1.0.0 h1:5J4U0kXF+pv/DhiXt5/lTz0eO5ogJ1iXb8Yj1yReDqE=
+github.com/ebitengine/hideconsole v1.0.0/go.mod h1:hTTBTvVYWKBuxPr7peweneWdkUwEuHuB3C1R/ielR1A=
+github.com/ebitengine/purego v0.11.0 h1:jhp/D+Nyv7UUW8HAcmcjt2N2rYrYi9m3SL21k0Ua/NI=
+github.com/ebitengine/purego v0.11.0/go.mod h1:DCHPP08djqhNSoTfImcnHYQRZmd0qhakvrozqaEYhGQ=
+github.com/go-gl/gl v0.0.0-20260331235117-4566fea9a276 h1:IO5P06Pcj9K04d+l4nrf3c2U56+dAotIFG6u4P1wAHI=
+github.com/go-gl/gl v0.0.0-20260331235117-4566fea9a276/go.mod h1:9YTyiznxEY1fVinfM7RvRcjRHbw2xLBJ3AAGIT0I4Nw=
+github.com/go-gl/glfw/v3.3/glfw v0.0.0-20260823155953-d41da22a9587 h1:yzPGEmWIlLQvQ0HvNHpRzLwyJ3pAmVXpa6pGclnH9Ks=
+github.com/go-gl/glfw/v3.3/glfw v0.0.0-20260823155953-d41da22a9587/go.mod h1:SyRD8YfuKk+ZXlDqYiqe1qMSqjNgtHzBTG810KUagMc=
+github.com/hajimehoshi/ebiten/v2 v2.10.2 h1:uNMOpfb/pW7GQRMsSn/pxwrk9rNcgSaIdjKwFZS11LM=
+github.com/hajimehoshi/ebiten/v2 v2.10.2/go.mod h1:47QNgyS/y2ZRkjVUvlGLx8a+F7MSjcn8/GsjcCZ9Rc8=
+github.com/klauspost/cpuid/v2 v2.4.0 h1:S6Hrbc7+ywsr0r+RLapfGBHfyefhCTwEh3A0tV913Dw=
+github.com/klauspost/cpuid/v2 v2.4.0/go.mod h1:19jmZ9mjzoF//ddRSUsv0zfBTJWh3QJh9FNxZTMrGxU=
+github.com/stretchr/testify v1.12.1 h1:EuwCh5fleGS7H32xRwO3wRGT7DxrDhLAT6FF8MpWDWE=
+github.com/stretchr/testify v1.12.1/go.mod h1:MDEgiDPPsNp5cuIrHPPCyornHKgEVbtFUmoNlxoYthg=
 github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
 github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
 github.com/zeebo/bencode v1.0.0 h1:zgop0Wu1nu4IexAZeCZ5qbsjU4O1vMrfCrVgUjbHVuA=
 github.com/zeebo/bencode v1.0.0/go.mod h1:Ct7CkrWIQuLWAy9M3atFHYq4kG9Ao/SsY5cdtCXmp9Y=
 github.com/zeebo/xxh3 v1.1.0 h1:s7DLGDK45Dyfg7++yxI0khrfwq9661w9EN78eP/UZVs=
 github.com/zeebo/xxh3 v1.1.0/go.mod h1:IisAie1LELR4xhVinxWS5+zf1lA4p0MW4T+w+W07F5s=
-golang.org/x/sys v0.44.0 h1:ildZl3J4uzeKP07r2F++Op7E9B29JRUy+a27EibtBTQ=
-golang.org/x/sys v0.44.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
-golang.org/x/term v0.41.0 h1:QCgPso/Q3RTJx2Th4bDLqML4W6iJiaXFq2/ftQF13YU=
-golang.org/x/term v0.41.0/go.mod h1:3pfBgksrReYfZ5lvYM0kSO0LIkAl4Yl2bXOkKP7Ec2A=
-gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
-gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+go.yaml.in/yaml/v3 v3.0.5 h1:N6y/pJk8buWs9NY5ERU2HSMfm+IuD/OtfdAnq6kESPw=
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