From 39b3c4bf34b3720b1af5b2380406c9e037686344 Mon Sep 17 00:00:00 2001
From: Marc-Andre Lafortune <github@marc-andre.ca>
Date: Tue, 26 May 2020 06:41:28 -0400
Subject: [PATCH] Add legacy switches to ruby-parse and ruby-rewrite

---
 lib/parser/runner.rb      | 23 +++++++++++++++++++++--
 test/test_runner_parse.rb | 21 +++++++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/lib/parser/runner.rb b/lib/parser/runner.rb
index 82a493ccb..1d840907d 100644
--- a/lib/parser/runner.rb
+++ b/lib/parser/runner.rb
@@ -14,9 +14,8 @@ def self.go(options)
     end
 
     def initialize
-      Parser::Builders::Default.modernize
-
       @option_parser = OptionParser.new { |opts| setup_option_parsing(opts) }
+      @legacy = {}
       @parser_class  = nil
       @parser        = nil
       @files         = []
@@ -30,6 +29,7 @@ def initialize
 
     def execute(options)
       parse_options(options)
+      setup_builder_default
       prepare_parser
 
       process_all_input
@@ -37,6 +37,8 @@ def execute(options)
 
     private
 
+    LEGACY_MODES = %i[lambda procarg0 encoding index arg_inside_procarg0].freeze
+
     def runner_name
       raise NotImplementedError, "implement #{self.class}##{__callee__}"
     end
@@ -126,6 +128,17 @@ def setup_option_parsing(opts)
         @parser_class = Parser::RubyMotion
       end
 
+      opts.on '--legacy', "Parse with all legacy modes" do
+        @legacy = Hash.new(true)
+      end
+
+      LEGACY_MODES.each do |mode|
+        opt_name = "--legacy-#{mode.to_s.gsub('_', '-')}"
+        opts.on opt_name, "Parse with legacy mode for emit_#{mode}" do
+          @legacy[mode] = true
+        end
+      end
+
       opts.on '-w', '--warnings', 'Enable warnings' do |w|
         @warnings = w
       end
@@ -164,6 +177,12 @@ def parse_options(options)
       end
     end
 
+    def setup_builder_default
+      LEGACY_MODES.each do |mode|
+        Parser::Builders::Default.send(:"emit_#{mode}=", !@legacy[mode])
+      end
+    end
+
     def prepare_parser
       @parser = @parser_class.new
 
diff --git a/test/test_runner_parse.rb b/test/test_runner_parse.rb
index f4fbe2733..e43d9b9d2 100644
--- a/test/test_runner_parse.rb
+++ b/test/test_runner_parse.rb
@@ -18,6 +18,27 @@ def test_emit_ruby
                   's(:int, 123)'
   end
 
+  def test_emit_modern_ruby
+    assert_prints ['-e', '->{}'],
+                  '(lambda)'
+    assert_prints ['-e', 'self[1] = 2'],
+                  'indexasgn'
+  end
+
+  def test_emit_legacy
+    assert_prints ['--legacy', '-e', '->{}'],
+                  '(send nil :lambda)'
+    assert_prints ['--legacy', '-e', 'self[1] = 2'],
+                  ':[]='
+  end
+
+  def test_emit_legacy_lambda
+    assert_prints ['--legacy-lambda', '-e', '->{}'],
+                  '(send nil :lambda)'
+    assert_prints ['--legacy-lambda', '-e', 'self[1] = 2'],
+                  'indexasgn'
+  end
+
   def test_emit_json
     assert_prints ['--emit-json', '-e', '123'],
                   '["int",123]'