From 7d460c6daa22791d449cc5546552b282633e20b4 Mon Sep 17 00:00:00 2001
From: Paul Liverman III <paul.liverman.iii@gmail.com>
Date: Sun, 11 Feb 2018 14:18:07 -0800
Subject: [PATCH] should be ready for initial use

---
 example.locator_config.moon |  9 +++++
 init.moon                   | 73 +++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100644 example.locator_config.moon
 create mode 100644 init.moon

diff --git a/example.locator_config.moon b/example.locator_config.moon
new file mode 100644
index 0000000..77ed5b2
--- /dev/null
+++ b/example.locator_config.moon
@@ -0,0 +1,9 @@
+{
+  {
+    path: "applications.users" -- there is a sub-application at this location relative to the repository's root
+    migrations: {after: 1518414112} -- don't run any migrations earlier than this one
+  }
+  {
+    path: "utility" -- another sub-application is here
+  }
+}
diff --git a/init.moon b/init.moon
new file mode 100644
index 0000000..e2a990e
--- /dev/null
+++ b/init.moon
@@ -0,0 +1,73 @@
+config = require "locator_config"
+
+import insert, sort from table
+
+-- locates and returns a module, or errors
+--  if priority (path) specified, will check it before other paths
+--  checks project root first, then each path specified in locator_config
+try_require = (path, priority) ->
+  if priority
+    ok, value = pcall -> require "#{priority}.#{path}"
+    return value if ok
+
+  ok, value = pcall -> require path
+  return value if ok
+
+  for item in *config
+    ok, value = pcall -> require "#{item.path}.#{path}"
+    return value if ok
+
+  error "locator could not find '#{path}'"
+
+-- works like Lapis's autoload, but
+--  includes trying sub-application paths & can be called to access a value
+autoload = (path, tab={}) ->
+  return setmetatable tab, {
+    __call: (t, name) ->
+      t[name] = try_require name, path
+      return t[name]
+    __index: (t, name) ->
+      t[name] = try_require name, path
+      return t[name]
+  }
+
+-- pass your migrations, it returns them + all sub-application migrations
+--  (legacy) see example config for how to specify to not include early migrations
+migrations = (app_migrations={}) ->
+  for item in *config
+    ok, migrations = pcall -> require "#{item.path}.migrations"
+    if ok
+      sorted = {}
+      for m in pairs migrations
+        insert sorted, m
+      sort sorted
+      for i in *sorted
+        -- only allow migrations after specified config value, or if no 'after' is specified
+        if (item.migrations and ((item.migrations.after and i > item.migrations.after) or not item.migrations.after)) or not item.migrations
+          -- if your migrations and theirs share a value, combine them
+          if app_fn = app_migrations[i]
+            app_migrations[i] = (...) ->
+              app_fn(...)
+              migrations[i](...)
+          -- else just add them
+          else
+            app_migrations[i] = migrations[i]
+
+  return app_migrations
+
+-- return access to autoload and migrations functions,
+--  and metamethods for getting autoloaders
+return setmetatable {
+  :autoload, :migrations
+}, {
+  __call: (t, here) ->
+    if "init" == here\sub -4
+      here = here\sub 1, -6
+    unless here
+      here = ""
+    return autoload here
+
+  __index: (t, name) ->
+    t[name] = autoload name
+    return t[name]
+}