From 4dfe9554cb35b27da983251a6599a4f9455a8bf0 Mon Sep 17 00:00:00 2001
From: Gwenhael Le Moine <gwenhael.le.moine@gmail.com>
Date: Tue, 4 Oct 2022 16:49:24 +0200
Subject: [PATCH] Persist stack and variable in ~/.local/state/rpl.rb/machine

---
 README.md              |  4 ----
 bin/rpl                | 32 +++++++++++++++++++++++---------
 lib/rpl.rb             | 39 +++++++++++++++++++++++++++++++++++++--
 lib/rpl/interpreter.rb | 17 ++++++++++++-----
 4 files changed, 72 insertions(+), 20 deletions(-)

diff --git a/README.md b/README.md
index 42de832..5857b05 100644
--- a/README.md
+++ b/README.md
@@ -12,10 +12,6 @@ To build gem: `rake gem`
  -
 
 # TODO-list
-  * REPL:
-    * autosave/autoload stack and vars from ~/.rplenv on start/exit
-      . autoload is just « '~/.rplenv' feval »
-      . autosave on exit overwrites
   * Language:
     * pseudo filesystem: subdir/namespace for variables
       . 'a dir' crdir 'a dir' cd vars
diff --git a/bin/rpl b/bin/rpl
index a40164c..e5cd4ce 100755
--- a/bin/rpl
+++ b/bin/rpl
@@ -8,9 +8,7 @@ require 'readline'
 require 'rpl'
 
 class RplRepl
-  def initialize( interpreter )
-    interpreter ||= Rpl.new
-
+  def initialize( interpreter: Rpl.new )
     @interpreter = interpreter
   end
 
@@ -51,11 +49,25 @@ class RplRepl
 end
 
 options = { run_REPL: ARGV.empty?,
+            persistence_filename: File.expand_path( '~/.local/state/rpl.rb/machine' ),
+            live_persistence: true,
             files: [],
             programs: [] }
 
 OptionParser.new do |opts|
-  opts.on('-c', '--code "program"', ' ') do |program|
+  opts.on('-s', "--state filename", "persist state in filename (default: #{options[:persistence_filename]}) (will be created if needed)") do |filename|
+    options[:persistence_filename] = File.expand_path( filename )
+  end
+
+  opts.on('-q', '--no-state', 'Do not load persisted state') do
+    options[:persistence_filename] = nil
+  end
+
+  opts.on('-d', '--no-persist', 'Do not persist state') do
+    options[:live_persistence] = false
+  end
+
+  opts.on('-c', '--code "program"', 'run provided "program"') do |program|
     options[:programs] << program
   end
 
@@ -69,7 +81,8 @@ OptionParser.new do |opts|
 end.parse!
 
 # Instantiate interpreter
-interpreter = Rpl.new
+interpreter = Rpl.new( persistence_filename: options[:persistence_filename],
+                       live_persistence: options[:live_persistence] )
 
 # first run provided files if any
 options[:files].each do |filename|
@@ -82,7 +95,8 @@ options[:programs].each do |program|
 end
 
 # third launch REPL if (explicitely or implicitely) asked
-RplRepl.new( interpreter ).run if options[:run_REPL]
-
-# last print defined vars and resulting stack on exit (formatted so that it can be fed back later to interpreter)
-pp "#{interpreter.export_vars} #{interpreter.export_stack}"
+if options[:run_REPL]
+  RplRepl.new( interpreter: interpreter ).run
+else
+  interpreter.persist_state
+end
diff --git a/lib/rpl.rb b/lib/rpl.rb
index 762118b..387c6e8 100644
--- a/lib/rpl.rb
+++ b/lib/rpl.rb
@@ -7,10 +7,45 @@ require 'rpl/words'
 class Rpl < Interpreter
   include Types
 
-  def initialize( stack = [], dictionary = Dictionary.new )
-    super
+  attr_accessor :live_persistence
+
+  def initialize( stack: [],
+                  dictionary: Dictionary.new,
+                  persistence_filename: nil,
+                  live_persistence: true )
+    super( stack: stack, dictionary: dictionary )
+
+    @persistence_filename = persistence_filename
+    @live_persistence = live_persistence
 
     populate_dictionary if @dictionary.words.empty?
+
+    load_persisted_state
+  end
+
+  def load_persisted_state
+    return if @persistence_filename.nil?
+
+    FileUtils.mkdir_p( File.dirname( @persistence_filename ) )
+    FileUtils.touch( @persistence_filename )
+
+    run "\"#{@persistence_filename}\" feval"
+  end
+
+  def persist_state
+    return if @persistence_filename.nil?
+
+    File.open( @persistence_filename, 'w' ) do |persistence_file|
+      persistence_file.write "#{export_vars}\n#{export_stack}"
+    end
+  end
+
+  def run( input )
+    stack = super
+
+    persist_state if @live_persistence
+
+    stack
   end
 
   prepend RplLang::Words::Branch
diff --git a/lib/rpl/interpreter.rb b/lib/rpl/interpreter.rb
index a36eb83..df22768 100644
--- a/lib/rpl/interpreter.rb
+++ b/lib/rpl/interpreter.rb
@@ -36,7 +36,7 @@ class Interpreter
 
   attr_accessor :precision
 
-  def initialize( stack = [], dictionary = Rpl::Lang::Dictionary.new )
+  def initialize( stack: [], dictionary: Dictionary.new )
     @version = 0.91
 
     @dictionary = dictionary
@@ -100,12 +100,19 @@ class Interpreter
   end
 
   def export_vars
-    @dictionary.vars
-               .map { |name, value| "#{value} '#{name}' sto" }
-               .join(' ')
+    vars_as_string = "@ variables:\n"
+    vars_as_string += @dictionary.vars
+                                 .map { |name, value| "#{value}\n'#{name}' sto\n" }
+                                 .join("\n")
+
+    vars_as_string
   end
 
   def export_stack
-    @stack.map(&:to_s).join(' ')
+    stack_as_string = "@ stack:\n"
+    stack_as_string += @stack.map(&:to_s)
+                             .join("\n")
+
+    stack_as_string
   end
 end