From effa8e488cf154b23ad535f4d580c13d3c9e4acc Mon Sep 17 00:00:00 2001
From: Michiel Borkent <michielborkent@gmail.com>
Date: Mon, 26 Oct 2020 11:21:11 +0100
Subject: [PATCH] wip

---
 src/babashka/impl/uberscript.clj | 66 ++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 src/babashka/impl/uberscript.clj

diff --git a/src/babashka/impl/uberscript.clj b/src/babashka/impl/uberscript.clj
new file mode 100644
index 00000000..e630082c
--- /dev/null
+++ b/src/babashka/impl/uberscript.clj
@@ -0,0 +1,66 @@
+(ns babashka.impl.uberscript
+  (:require [clojure.java.io :as io]
+            [clojure.pprint :as pprint]
+            [clojure.string :as str]
+            [sci.core :as sci]))
+
+(defn rewrite-ns
+  "Rewrites ns form :require clauses into symbols + :reload only."
+  [ns]
+  (keep (fn [x]
+          (if (seq? x)
+            (cond (= :require-macros (first x)) nil ;; ignore
+                  (= :require (first x))
+                  (let [nss (keep (fn [x]
+                                    (cond (seqable? x) (first x)
+                                          (symbol? x) x))
+                                 (rest x))]
+                    (cons :require (interpose :reload nss)))) ;; force reload
+            x))
+          ns))
+
+(defn ns->files [dir ns]
+  (let [extensions ["clj" "cljs" "cljc"]
+        path (-> ns munge (str/replace "." java.io.File/separator))
+        files (map #(io/file dir (str path "." %)) extensions)]
+    (filter #(.exists ^java.io.File %) files)))
+
+(def ^:dynamic *ctx* nil)
+(def ^:dynamic *ns-path* nil)
+(def debug true)
+
+(defn process-source [file]
+  (let [file-reader (io/reader (io/file file))
+        source-reader (sci/reader file-reader)]
+    (loop []
+      (let [next-form (sci/parse-next *ctx* source-reader)]
+        (when-not (= ::sci/eof next-form)
+          (if (and (seq? next-form)
+                   (= 'ns (first  next-form)))
+            (let [ns (rewrite-ns next-form)]
+              (sci/eval-form *ctx* ns))
+            ;; look for more ns forms
+            (recur)))))))
+
+(defn uberscript [init-code namespace skip-namespaces resource-fn]
+  (let [uberscript-sources (atom ())
+        load-fn (fn [{:keys [:namespace :reload]}]
+                  (when resource-fn
+                    (if ;; ignore built-in namespaces when uberscripting, unless with :reload
+                        (and uberscript
+                             (not reload)
+                             (not (contains? skip-namespaces namespace)))
+                      ""
+                      (let [res (resource-fn namespace)]
+                        (when uberscript (swap! uberscript-sources conj (:source res)))
+                        res))))
+        namespace (symbol namespace)
+        results (atom {namespace nil})
+        ctx (sci/init {:load-fn load-fn
+                       :features #{:bb :clj}})]
+    ;; establish a thread-local bindings to allow set!
+    (sci/with-bindings {sci/ns @sci/ns}
+      (binding [*ctx* ctx
+                *ns-path* [namespace]]
+        (process-source init-code)))))
+