Modify: add new class OutvokeProcExecContext

This commit makes the following changes:

  - add new class OutvokeProcExecContext
  - add new feature "to" method
  - change to use instance_exec in two places

These will allow you can write like following:

hook("every-sec", / ..:..:.[02468]/) { to "lo" }

Since loputs are already provided for the data source "lo", the above
code is equivalent to writing this:

hook("every-sec", / ..:..:.[02468]/) { loputs _1.body }

Using instance_exec allows you to write something like `to "lo"`.

OutvokeProcExecContext is a class provided only for instance_exec.

Ever since the initial release of outvoke.rb (35a76256), Proc#call
has simply been used to execute Proc objects registered by hook.
With this commit, for the first time, a change is being made here
so that instance_exec will be used.

Note that the impact of this has not been fully tested.

BTW, This commit is related to 7dba2139 and 9a253737.

outvoke.rb

 #!/usr/bin/env ruby
 #
 # ==========================================================================
-# Outvoke -- version 0.0.99.20241107.1
+# Outvoke -- version 0.0.99.20241107.2
 #
 # written by cleemy desu wayo / Licensed under CC0 1.0
 #
@@ -23,7 +23,7 @@ class Outvoke
 
     @version = Struct.new(:branch, :body).new(
       '0.1',
-      '0.0.99.20241107.1'
+      '0.0.99.20241107.2'
     )
 
     @sources = Hash.new
@@ -209,7 +209,12 @@ class Outvoke
       event.m = event.m.to_a   # with Marshal.#dump in mind
 
       hook_result = nil
-      hook_result = hook['proc'].call(event) if hook['proc']    # execute
+
+      # execute
+      if hook['proc']
+        tmp_context = OutvokeProcExecContext.new(self, event)
+        hook_result = tmp_context.instance_exec(event, &hook['proc'])
+      end
 
       is_log_outputted = false
       if hook_result.is_a?(String)
@@ -247,6 +252,24 @@ class Outvoke
 
 end
 
+#
+# this class provided only for instance_exec
+#
+class OutvokeProcExecContext
+  def initialize(outvoke, event)
+    @outvoke = outvoke
+    @event = event
+    @event_body = @event.body.dup
+  end
+
+  def to(ds_cond)
+    @outvoke.extract_ds(ds_cond).each do |ds_label|
+      @outvoke.sources[ds_label].lo_data << @event_body
+    end
+    nil
+  end
+end
+
 module OutvokeDSL
   refine Kernel do
     def hook(ds_cond, event_cond = /./, &block)
@@ -270,7 +293,7 @@ module OutvokeDSL
       if block_given?
         hook(ds_cond, event_cond) do |x|
           tmp = Marshal.load(Marshal.dump(x))    # deep copy
-          Thread.start { yield tmp }
+          Thread.start { instance_exec(tmp, &block) }
           nil
         end
       else