export evaluation from default.nix and use it for docs

doc/extract-options.nix

@@ -1,31 +1,10 @@
+{ eval, lib, pkgs }:
 let
-  overlay = import ../overlay.nix;
-  pkgs = import <nixpkgs> ( {
-    overlays = [overlay];
-    config = {
-      allowUnsupportedSystem = true; # mipsel
-      permittedInsecurePackages = [
-        "python-2.7.18.6"       # kernel backports needs python <3
-      ];
-    };
-  });
-  inherit (pkgs) lib;
   inherit (lib) types;
-  modulenames =
-    builtins.attrNames
-      (lib.filterAttrsRecursive
-        (n: t:
-          (n != "arch") &&
-          ((t=="directory") ||
-           ((t=="regular") && ((builtins.match ".*\\.nix$" n) != null))))
-        (builtins.readDir ../modules));
-  modulefiles = builtins.map (n: builtins.toPath "${../modules}/${n}") modulenames;
-  eval = (lib.evalModules {
-    modules = [
-      { _module.args = { inherit pkgs; lib = pkgs.lib; }; }
-    ] ++ modulefiles;
-  });
   conf = eval.config;
+  rootDir = builtins.toPath ./..;
+  stripAnyPrefixes = lib.flip (lib.fold lib.removePrefix)
+    ["${rootDir}/"];
   optToDoc = name: opt : {
     inherit name;
     description = opt.description or null;
@@ -42,16 +21,12 @@ let
     then
       let sd = lib.attrByPath item.loc ["not found"] conf;
       in item // {
+        declarations =  map stripAnyPrefixes item.declarations;
         parameters =
           let x = lib.mapAttrsToList optToDoc sd.parameters; in x;
       }
     else
-      item;
-  o = builtins.map spliceServiceDefn
-    (pkgs.lib.optionAttrSetToDocList eval.options);
-in {
-  doc = pkgs.writeText "options.yaml" ''
-    # ${./..}
-    ${builtins.toJSON o}
-  '';
-}
+      item // { declarations =  map stripAnyPrefixes item.declarations; };
+in
+builtins.map spliceServiceDefn
+  (pkgs.lib.optionAttrSetToDocList eval.options)

doc/parse-options.fnl

@@ -2,21 +2,25 @@
 
 (local { : view } (require :fennel))
 
+(fn basename [str ext]
+  (-> str
+      (string.gsub "(.*/)(.*)" "%2")
+      (string.gsub (.. ext "$") "")))
+
 (fn headline [name]
-  (let [(_ _ basename) (string.find name ".*/([^/].*).nix")
-        len (basename:len)]
-    (.. basename "\n" (string.rep "=" len))))
+  (let [title (assert (basename name ".nix"))
+        len (title:len)]
+    (.. title "\n" (string.rep "=" len))))
 
 (fn read-preamble [pathname]
-  (if (= (pathname:sub 1 1) "/")
-      (let [pathname (if (string.match pathname ".nix$")
-                         pathname
-                         (.. pathname "/default.nix"))]
-        (with-open [f (assert (io.open pathname :r))]
-          (accumulate [lines nil
-                       l (f:lines)
-                       :until (not (= (string.sub l 1 2) "##"))]
-            (.. (or lines "") (string.gsub l "^## *" "") "\n"))))))
+  (let [pathname (if (string.match pathname ".nix$")
+                     pathname
+                     (.. pathname "/default.nix"))]
+    (with-open [f (assert (io.open pathname :r))]
+      (accumulate [lines nil
+                   l (f:lines)
+                   :until (not (= (string.sub l 1 2) "##"))]
+        (.. (or lines "") (string.gsub l "^## *" "") "\n")))))
 
 (fn relative-pathname [pathname]
   (let [pathname