feat: faster parser (#3)

* fix(load): support nested objects

* feat: initial golang parser

Moves most of load.libsonnet to a Golang app for hopefully much faster
parsing (fingers crossed)

* feat(fast): nested objects, subpackages

* feat: incorporate fast mode into main binary

Moves the work done in the fast directory into the main executable,
removing the Jsonnet based parser in favor of the much faster Golang one.

load.libsonnet

@@ -1,59 +1,24 @@
 local lib = {
-  // reshape converts the Jsonnet structure to the one used by docsonnet:
-  // - put fields into an `api` key
-  // - put subpackages into `sub` key
-  reshape(pkg)::
-    local aux(old, key) =
-      if key == '#' then
-        old
-      else if std.objectHas(pkg[key], '#') then
-        old { sub+: { [key]: $.package(pkg[key]) } }
-      else
-        old { api+: { [key]: pkg[key] } };
-
-    std.foldl(aux, std.objectFields(pkg), {})
-    + pkg['#'],
-
-  // fillObjects creates docsonnet objects from Jsonnet ones,
-  // also filling those that have been specified explicitely
-  fillObjects(api)::
+  scan(obj)::
     local aux(old, key) =
       if std.startsWith(key, '#') then
-        old { [key]: api[key] }
-      else if std.isObject(api[key]) && std.length(std.objectFields(api[key])) > 0 then
-        old { ['#' + key]+: { object+: {
-          fields: api[key],
-        } } }
+        true
+      else if std.isObject(obj[key]) then
+        old || $.scan(obj[key])
+      else old;
+    std.foldl(aux, std.objectFieldsAll(obj), false),
+
+  load(pkg)::
+    local aux(old, key) =
+      if !std.isObject(pkg[key]) then
+        old
+      else if std.startsWith(key, '#') then
+        old { [key]: pkg[key] }
+      else if self.scan(pkg[key]) then
+        old { [key]: $.load(pkg[key]) }
       else old;
 
-    std.foldl(aux, std.objectFields(api), {}),
-
-  // clean removes all hashes from field names
-  clean(api):: {
-    [std.lstripChars(key, '#')]:
-      if std.isObject(api[key]) then $.clean(api[key])
-      else api[key]
-    for key in std.objectFields(api)
-  },
-
-  cleanNonObj(api):: {
-    [key]:
-      if std.startsWith(key, "#") then api[key]
-      else if std.isObject(api[key]) then $.cleanNonObj(api[key])
-      else api[key]
-    for key in std.objectFieldsAll(api)
-    if std.isObject(api[key])
-  },
-
-  // package loads docsonnet from a Jsonnet package
-  package(pkg)::
-    local cleaned = self.cleanNonObj(pkg);
-    local reshaped = self.reshape(cleaned);
-    local filled =
-      if std.objectHas(reshaped, 'api')
-      then reshaped { api: $.fillObjects(reshaped.api) }
-      else reshaped;
-    self.clean(filled),
+    std.foldl(aux, std.objectFieldsAll(pkg), {}),
 };
 
-lib.package(std.extVar("main"))
+lib.load(std.extVar('main'))