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jolt/doc/tools-deps.md
Yogthos 761a2b8f72 support type hints; make metadata coherent 
The reader expanded ^X form to (with-meta form X), which evaluated the tag (so
^String errored 'Unable to resolve symbol: String') and, as a param, was no
longer a bare symbol (so the arg bound to nil). Now a keyword/symbol/string hint
on a symbol attaches to the symbol's :meta and the symbol stays bare, so type
hints are transparent in params, lets, and bodies. Map metadata still uses a
runtime with-meta form.

meta now returns a symbol's :meta, and def applies the name's metadata
(^:dynamic, ^:private, ^Type tag, ^{:doc}) to the var, so (meta (var x)) is
consistent. Specs in metadata-spec; grammar note in the ebnf.

README notes regex \p{...} as unsupported (separate from this).
2026-06-06 00:36:10 -04:00

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deps.edn support — design notes

How Jolt loads pure-Clojure libraries from a deps.edn, and why it's built the way it is. For how to use it, see building-and-deps.md.

Scope, decided up front:

  • git + local deps only — no Maven/~/.m2 resolution.
  • pure clj/cljc — anything needing the JVM won't load or run; expected.
  • no classpath abstraction — require just needs to find a dep's namespaces; "the classpath" is an ordered list of source directories.
  • piggyback on jpm — reuse jpm's git fetch + cache; don't write a package manager.
  • separate tool — resolution lives in jolt-deps, beside the runtime, the way jpm sits beside janet. The jolt runtime knows nothing about deps.edn.

How jpm handles dependencies

jpm's package code (jpm/pm.janet) splits into a fetch half and a build half, and we use only the first:

  • resolve-bundle normalizes a dep spec to {:url :tag :type :shallow}, accepting :url/:repo + :tag/:sha/:commit/:ref. A deps.edn {:git/url … :git/sha …} maps straight onto it.
  • download-bundle url :git tag shallow clones into a content-addressed cache (<modpath>/.cache/git_<tag>_<sanitized-url>) and returns the path — git init + remote add + fetch + reset, plus submodules. No build step.
  • bundle-install is the half we skip: it then runs project.janet build rules, which a Clojure lib doesn't have. It's cleanly separable from the clone.

So jpm gives us git resolution and a cache for free; calling download-bundle needs jpm/config/load-default first (it sets gitpath and the cache dyns).

How it works

src/jolt/deps.janet reads deps.edn (Janet parses it directly — EDN and Janet syntax overlap for the :deps/:paths subset), then walks :deps:

  • :git/url (+ :git/sha or :git/tag) → resolve-bundle + download-bundle into jpm_tree/.cache;
  • :local/root → the path as-is;
  • :mvn/* and anything else → ignored.

Each resolved dependency contributes its own :paths (default ["src"]) as source roots, and we recurse into its deps.edn for transitive deps. The result is a de-duplicated, ordered list of directories. resolve-deps-cached memoizes that list in the tree keyed on a hash of deps.edn, so an unchanged file doesn't re-fetch. jpm is loaded lazily (require, not import) so it's pulled in only when resolving — never embedded in a built binary.

The loader (evaluator.janet/find-ns-file) resolves a namespace by searching the context's :source-paths in order (the stdlib src/jolt first), trying <ns>.clj then <ns>.cljc. Extra roots come from JOLT_PATH or init's :paths option.

jolt-deps (src/jolt/deps_cli.janet, its own declare-executable) ties it together: it resolves the roots and runs the jolt binary with them on JOLT_PATH. The runtime's only dependency interface is that env var.

jolt uberscript bundles a namespace and everything it requires into one standalone .clj. It requires the entry namespace and uses the order in which the loader finishes loading files — a dependency finishes before the file that required it, so the order is topological — then concatenates that source. The baked-in stdlib is excluded (it's part of the runtime, not bundled).

Gotcha worth remembering: the jolt CLI's context is built into its image at build time, so JOLT_PATH is applied at runtime in main, not in init (whose env read would be frozen at build).

Limitations

  • Pure clj/cljc only — JVM interop, host classes, and unimplemented clojure.core corners fail. Coverage is per-function: a namespace can load with most functions working and a few not.
  • Source only; compiled .class files in a git dep are ignored.
  • git :git/sha must be a full SHA (git fetch can't resolve a short one).

Conformance

test/integration/deps-conformance-test.janet resolves a few real pure-cljc git libraries and reports whether their namespaces load and a sample call works. It's network-gated behind JOLT_CONFORMANCE=1 so CI stays offline. Use it to check a library against the current interpreter, and to drive fixes for whatever gap a failure points at (the same loop as the clojure-test-suite battery). A library fails when it relies on something Jolt doesn't provide — JVM interop, or a regex feature like Unicode property classes (\p{…}).

Not yet

  • Compiling deps into a binary image. uberscript already produces a standalone .clj; baking a project's dependencies directly into a custom executable image is a heavier variant that isn't implemented.