move into proper Lua module (`alv`)

1 files changed, 85 insertions, 0 deletions

diff --git a/alv/copilot.moon b/alv/copilot.moon
new file mode 100644
index 0000000..478cbae
--- /dev/null
+++ b/alv/copilot.moon
@@ -0,0 +1,85 @@
+----
+-- File watcher and CLI entrypoint.
+--
+-- @classmod Copilot
+lfs = require 'lfs'
+import Scope from require 'alv.scope'
+import Registry from require 'alv.registry'
+import Error from require 'alv.error'
+import program from require 'alv.parsing'
+globals = Scope.from_table require 'alv.builtin'
+
+slurp = (file) ->
+  file = io.open file, 'r'
+  with file\read '*all'
+    file\close!
+
+spit = (file, str) ->
+  file = io.open file, 'w'
+  file\write str
+  file\close!
+
+class Copilot
+--- static functions
+-- @section static
+
+  --- create a new Copilot.
+  -- @classmethod
+  -- @tparam string file name/path of the alive file to watch and execute
+  new: (@file) =>
+    @registry = Registry!
+
+    @last_modification = 0
+
+    mode = lfs.attributes @file, 'mode'
+    if mode != 'file'
+      error "not a file: #{@file}"
+
+--- members
+-- @section members
+
+  --- poll for changes and tick.
+  tick: =>
+    @poll!
+
+    if @root
+      @registry\begin_tick!
+      ok, error = Error.try "updating", ->
+        @root\tick_io!
+        @root\tick!
+      if not ok
+        print error
+      @registry\end_tick!
+
+  eval: =>
+    @registry\begin_eval!
+    ok, ast = Error.try "parsing '#{@file}'", program\match, slurp @file
+    if not (ok and ast)
+      print ast or Error 'syntax', "failed to parse"
+      @registry\rollback_eval!
+      return
+
+    scope = Scope globals
+    ok, root = Error.try "evaluating '#{@file}'", ast\eval, scope, @registry
+    if not ok
+      print root
+      @registry\rollback_eval!
+      return
+
+    @registry\end_eval!
+    @root = root
+    spit @file, ast\stringify!
+
+  poll: =>
+    { :mode, :modification } = (lfs.attributes @file) or {}
+    if mode != 'file'
+      return
+
+    if @last_modification < modification
+      L\log "#{@file} changed at #{modification}"
+      @eval!
+      @last_modification = os.time!
+
+{
+  :Copilot
+}