deps.edn resolution + a file loader + a project-aware CLI

joltc grew from a single -e expression into a real project runner. require now
loads a namespace's .clj/.cljc from the source roots transitively (load-once),
so a multi-file project works; the corpus/unit gates load compile-eval.ss but
not the loader, so their alias-only require is unchanged.

jolt.deps resolves a deps.edn into ordered source roots — git + local deps only
(no Maven), breadth-first so a top-level pin wins, with aliases (:extra-paths/
:extra-deps/:main-opts) and tasks. Git deps clone into a sha-immutable cache
($JOLT_GITLIBS, else ~/.jolt/gitlibs) by shelling out to git via a new
jolt.host/sh primitive. jolt.main dispatches run -m / -M:alias / -A / repl /
path / a deps.edn task. The launcher passes the user's cwd as JOLT_PWD (the
project dir) since it cd's to the repo root for the runtime's relative loads.

jolt-core/jolt/deps.clj

@@ -0,0 +1,125 @@
+(ns jolt.deps
+  "Resolve a deps.edn into an ordered list of source roots — git + local deps
+  only, no Maven. A reduced tools.deps: :paths, :deps (`:git/url`+`:git/sha` /
+  `:local/root`), :aliases (:extra-paths / :extra-deps / :main-opts), :tasks.
+
+  The deps walk is breadth-first so a top-level coordinate registers before any
+  transitive one (a top-level pin wins). Git deps clone into a sha-immutable
+  cache ($JOLT_GITLIBS, else ~/.jolt/gitlibs) shared across projects. Resolution
+  shells out to `git` through jolt.host/sh; nothing here touches the JVM."
+  (:require [clojure.edn :as edn]
+            [clojure.string :as str]))
+
+;; --- small host seams -------------------------------------------------------
+(defn- getenv [n] (jolt.host/getenv n))
+(defn- file-exists? [p] (jolt.host/file-exists? p))
+(defn- sh [cmd] (jolt.host/sh cmd))           ; exit code, inherits stdout/stderr
+(defn- sh-out [cmd] (jolt.host/sh-out cmd))   ; captured stdout
+(defn- warn [& xs] (println (str "[jolt.deps] " (apply str xs))))
+
+(defn- read-edn [path]
+  (when (file-exists? path)
+    (try (edn/read-string (slurp path))
+         (catch :default e (warn "could not read " path ": " (ex-message e)) nil))))
+
+(defn- abspath [dir p]
+  (if (str/starts-with? p "/") p (str dir "/" p)))
+
+;; --- git cache --------------------------------------------------------------
+(defn- gitlibs-dir []
+  (or (getenv "JOLT_GITLIBS")
+      (str (or (getenv "HOME") ".") "/.jolt/gitlibs")))
+
+(defn- alnum? [c]
+  (let [n (int c)]
+    (or (and (>= n 48) (<= n 57))     ; 0-9
+        (and (>= n 65) (<= n 90))     ; A-Z
+        (and (>= n 97) (<= n 122))))) ; a-z
+(defn- sanitize [s]
+  (str/join (map (fn [c] (if (or (alnum? c) (= c \.) (= c \-)) c \_)) (seq s))))
+
+(defn- ensure-git
+  "Clone url at sha into the cache (once); return the checkout dir."
+  [url sha]
+  (let [dir (str (gitlibs-dir) "/" (sanitize url) "/" sha)]
+    (if (file-exists? dir)
+      dir
+      (do
+        (warn "fetching " url " @ " (subs sha 0 (min 12 (count sha))))
+        (sh (str "mkdir -p " (pr-str dir)))
+        (when-not (zero? (sh (str "git clone --quiet " (pr-str url) " " (pr-str dir))))
+          (throw (ex-info (str "git clone failed: " url) {:url url})))
+        (when-not (zero? (sh (str "git -C " (pr-str dir) " checkout --quiet " (pr-str sha))))
+          (throw (ex-info (str "git checkout failed: " sha " in " url) {:url url :sha sha})))
+        ;; submodules are pinned in the checkout; pull them if the dep uses any.
+        (sh (str "git -C " (pr-str dir) " submodule update --init --recursive --quiet"))
+        dir))))
+
+;; --- coordinate -> root dir -------------------------------------------------
+(defn- coord-root
+  "The on-disk root directory for one dependency coordinate, or nil to skip."
+  [coord spec base-dir]
+  (cond
+    (:local/root spec) (abspath base-dir (:local/root spec))
+    (and (:git/url spec) (:git/sha spec))
+    (let [checkout (ensure-git (:git/url spec) (:git/sha spec))]
+      (if-let [root (:deps/root spec)] (str checkout "/" root) checkout))
+    (:jolt/module spec)
+    (do (warn "skipping janet dependency " coord " (:jolt/module is obsolete on Chez)") nil)
+    :else
+    (do (warn "skipping unsupported coordinate " coord " " (pr-str spec)) nil)))
+
+(defn- dep-source-roots
+  "Source roots a resolved dep contributes: its deps.edn :paths (default [\"src\"])
+  resolved under its root dir."
+  [root]
+  (let [edn (read-edn (str root "/deps.edn"))
+        paths (or (:paths edn) ["src"])]
+    (map #(abspath root %) paths)))
+
+(defn- resolve-deps
+  "Breadth-first walk of a deps map; returns an ordered, de-duplicated list of
+  source-root directories. `base-dir` resolves :local/root and is replaced by a
+  dep's own root as the walk descends."
+  [deps base-dir]
+  (loop [queue (mapv (fn [[c s]] [c s base-dir]) (seq deps))
+         seen #{}
+         roots []]
+    (if (empty? queue)
+      (distinct roots)
+      (let [[coord spec bd] (first queue)
+            queue (subvec (vec queue) 1)]
+        (if (contains? seen coord)
+          (recur queue seen roots)
+          (let [root (coord-root coord spec bd)]
+            (if (nil? root)
+              (recur queue (conj seen coord) roots)
+              (let [edn (read-edn (str root "/deps.edn"))
+                    child (mapv (fn [[c s]] [c s root]) (seq (:deps edn)))]
+                (recur (into queue child)
+                       (conj seen coord)
+                       (into roots (dep-source-roots root)))))))))))
+
+;; --- public -----------------------------------------------------------------
+(defn resolve-project
+  "Resolve `project-dir`'s deps.edn with the selected alias keywords. Returns
+  {:roots [...] :main-opts [...] :tasks {...}}; :main-opts is the last selected
+  alias's, else nil."
+  ([project-dir] (resolve-project project-dir []))
+  ([project-dir alias-kws]
+   (let [edn (read-edn (str project-dir "/deps.edn"))
+         aliases (:aliases edn)
+         selected (keep #(get aliases %) alias-kws)
+         extra-paths (mapcat :extra-paths selected)
+         extra-deps (apply merge (map :extra-deps selected))
+         main-opts (some :main-opts (reverse selected))
+         project-paths (concat (or (:paths edn) ["src"]) extra-paths)
+         project-roots (map #(abspath project-dir %) project-paths)
+         all-deps (merge (:deps edn) extra-deps)
+         dep-roots (resolve-deps all-deps project-dir)]
+     {:roots (vec (distinct (concat project-roots dep-roots)))
+      :main-opts main-opts
+      :tasks (:tasks edn)})))
+
+(defn has-deps-edn? [project-dir]
+  (file-exists? (str project-dir "/deps.edn")))