Backport lib/reline, and lib/irb for 3.0.1 4th (#4349)

* [ruby/irb] Update help message for next context-mode of 4

While here, fixing tab/space issues in help message, and sync
rdoc for IRB class to match the help message.

https://github.com/ruby/irb/commit/ef8e3901cc

* [ruby/irb] Do not continue line if last expression is an endless range

Fixes [Bug #14824]

https://github.com/ruby/irb/commit/63414f8465

* [ruby/irb] Add a test for not continuing when endless range at eol

https://github.com/ruby/irb/commit/1020ac9c65

* [ruby/irb] Make save-history extension safe for concurrent use

This makes the save-history extension check for modifications to
the history file before saving it.  If the history file was modified
after the history was loaded and before it was saved, append only
the new history lines to the history file.

This can result in more lines in the history file than SAVE_HISTORY
allows.  However, that will be fixed the next time irb is run and
the history is saved.

Fixes [Bug #13654]

https://github.com/ruby/irb/commit/041ef53845

* Fix errors when XDG_CONFIG_HOME points to non-writable directory

`$HOME/.config` is not writable on CI
because I think tests should not corrupt user's data.

And GitHub Actions CI sets `XDG_CONFIG_HOME`
since `Version: 20210309.1`.

https://github.com/ruby/actions/runs/2130811016?check_suite_focus=true#step:16:301
```
Errno::EACCES: Permission denied @ dir_s_mkdir - /home/runner/.config/irb
```

* Try to fix errors in TestIRB::TestHistory too

https://github.com/ruby/actions/runs/2137935523?check_suite_focus=true#step:9:562
```
  1) Error:
TestIRB::TestHistory#test_history_concurrent_use:
Errno::EACCES: Permission denied @ dir_s_mkdir - /home/runner/.config/irb
    /home/runner/work/actions/actions/ruby/lib/fileutils.rb:253:in `mkdir'
    /home/runner/work/actions/actions/ruby/lib/fileutils.rb:253:in `fu_mkdir'
    /home/runner/work/actions/actions/ruby/lib/fileutils.rb:231:in `block (2 levels) in mkdir_p'
    /home/runner/work/actions/actions/ruby/lib/fileutils.rb:229:in `reverse_each'
    /home/runner/work/actions/actions/ruby/lib/fileutils.rb:229:in `block in mkdir_p'
    /home/runner/work/actions/actions/ruby/lib/fileutils.rb:211:in `each'
    /home/runner/work/actions/actions/ruby/lib/fileutils.rb:211:in `mkdir_p'
    /home/runner/work/actions/actions/ruby/lib/irb/init.rb:355:in `rc_file_generators'
    /home/runner/work/actions/actions/ruby/lib/irb/init.rb:330:in `rc_file'
    /home/runner/work/actions/actions/ruby/test/irb/test_history.rb:170:in `block in assert_history'
    /home/runner/work/actions/actions/ruby/lib/tmpdir.rb:96:in `mktmpdir'
    /home/runner/work/actions/actions/ruby/test/irb/test_history.rb:168:in `assert_history'
    /home/runner/work/actions/actions/ruby/test/irb/test_history.rb:133:in `test_history_concurrent_use'
```

* [ruby/irb] Define "measure" command without forced override

https://github.com/ruby/irb/commit/9587ba13b5

* [ruby/irb] Add all lib files automatically

https://github.com/ruby/irb/commit/ecc82336b7

* [ruby/irb] Don't call Ruby 2.4+'s String#pretty_print

https://github.com/ruby/irb/commit/89bcf107be

* [ruby/irb] Implement ls command

https://github.com/ruby/irb/commit/19b6c20604

* [ruby/irb] Add whereami command

https://github.com/ruby/irb/commit/bc822e4aac

* [ruby/irb] Fix column overflow on ls output

https://github.com/ruby/irb/commit/6115754623

* [ruby/irb] Fix step's argument

cols.size was calling Integer#size, which returns 8.

Fixing a bug of https://github.com/ruby/irb/pull/209

https://github.com/ruby/irb/commit/c93ae4be71

* [ruby/irb] Deal with different screen sizes

e.g. http://rubyci.s3.amazonaws.com/centos8/ruby-master/log/20210321T063003Z.fail.html.gz

https://github.com/ruby/irb/commit/ddb3472ba2

* [ruby/irb] Have some right padding

instead of filling out an entire line

https://github.com/ruby/irb/commit/6ac8f45f5f

* Suppress verbose messages

Get rid of warnings in the parallel test.

```
unknown command: "Switch to inspect mode."
```

* [ruby/irb] Change ripper_lex_without_warning to a class method

https://github.com/ruby/irb/commit/d9f8abc17e

* [ruby/irb] Complete require and require_relative

https://github.com/ruby/irb/commit/1c61178b4c

* [ruby/reline] Add Reline.ungetc to control buffer

https://github.com/ruby/reline/commit/43ac03c624

* [ruby/reline] Reline.delete_text removes the current line in multiline

https://github.com/ruby/reline/commit/da90c094a1

* [ruby/reline] Support preposing and postposing for Reline.completion_proc

https://github.com/ruby/reline/commit/1f469de90c

* [ruby/reline] Suppress crashing when completer_{quote,word_break}_characters is empty

https://github.com/ruby/reline/commit/c6f1164942

* [ruby/irb] fix completion test when out-of-place build

* [ruby/irb] Cache completion files to require

https://github.com/ruby/irb/commit/612ebcb311

* [ruby/irb] Always add input method when calling Irb.new in tests

When passes input method as nil to Context.new through Irb.new,
ReidlineInputMethod.new is executed and the global internal state of Reline is
rewritten, therefore other tests are failed in the Ruby repository. This
commit changes to use TestInputMethod.

https://github.com/ruby/irb/commit/010dce9210

* [ruby/irb] Prevent the completion from crashing if rdoc is missing

There are cases where ruby is installed without rdoc and e.g.
lib/irb/cmd/help.rb also handles the LoadError

Here is how to replicate the issue:

```
$ docker run -it alpine:3.13.3 sh

/ # apk add ruby ruby-irb ruby-io-console

/ # irb

irb(main):001:0> Class[TAB][TAB]
```

And you end up with something like:

```
irb(main):001:0> ClassTraceback (most recent call last):
        34: from /usr/bin/irb:23:in `<main>'
        33: from /usr/bin/irb:23:in `load'
        32: from /usr/lib/ruby/gems/2.7.0/gems/irb-1.2.6/exe/irb:11:in `<top (required)>'
        31: from /usr/lib/ruby/2.7.0/irb.rb:400:in `start'
        30: from /usr/lib/ruby/2.7.0/irb.rb:471:in `run'
        29: from /usr/lib/ruby/2.7.0/irb.rb:471:in `catch'
        28: from /usr/lib/ruby/2.7.0/irb.rb:472:in `block in run'
        27: from /usr/lib/ruby/2.7.0/irb.rb:537:in `eval_input'
        26: from /usr/lib/ruby/2.7.0/irb/ruby-lex.rb:150:in `each_top_level_statement'
        25: from /usr/lib/ruby/2.7.0/irb/ruby-lex.rb:150:in `catch'
        24: from /usr/lib/ruby/2.7.0/irb/ruby-lex.rb:151:in `block in each_top_level_statement'
        23: from /usr/lib/ruby/2.7.0/irb/ruby-lex.rb:151:in `loop'
        22: from /usr/lib/ruby/2.7.0/irb/ruby-lex.rb:154:in `block (2 levels) in each_top_level_statement'
        21: from /usr/lib/ruby/2.7.0/irb/ruby-lex.rb:182:in `lex'
        20: from /usr/lib/ruby/2.7.0/irb.rb:518:in `block in eval_input'
        19: from /usr/lib/ruby/2.7.0/irb.rb:704:in `signal_status'
        18: from /usr/lib/ruby/2.7.0/irb.rb:519:in `block (2 levels) in eval_input'
        17: from /usr/lib/ruby/2.7.0/irb/input-method.rb:294:in `gets'
        16: from /usr/lib/ruby/2.7.0/forwardable.rb:235:in `readmultiline'
        15: from /usr/lib/ruby/2.7.0/forwardable.rb:235:in `readmultiline'
        14: from /usr/lib/ruby/2.7.0/reline.rb:175:in `readmultiline'
        13: from /usr/lib/ruby/2.7.0/reline.rb:238:in `inner_readline'
        12: from /usr/lib/ruby/2.7.0/reline.rb:238:in `loop'
        11: from /usr/lib/ruby/2.7.0/reline.rb:239:in `block in inner_readline'
        10: from /usr/lib/ruby/2.7.0/reline.rb:270:in `read_io'
         9: from /usr/lib/ruby/2.7.0/reline.rb:270:in `loop'
         8: from /usr/lib/ruby/2.7.0/reline.rb:311:in `block in read_io'
         7: from /usr/lib/ruby/2.7.0/reline.rb:240:in `block (2 levels) in inner_readline'
         6: from /usr/lib/ruby/2.7.0/reline.rb:240:in `each'
         5: from /usr/lib/ruby/2.7.0/reline.rb:241:in `block (3 levels) in inner_readline'
         4: from /usr/lib/ruby/2.7.0/reline/line_editor.rb:820:in `input_key'
         3: from /usr/lib/ruby/2.7.0/reline/line_editor.rb:608:in `complete'
         2: from /usr/lib/ruby/2.7.0/irb/completion.rb:269:in `block in <module:InputCompletor>'
         1: from /usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in `require'
/usr/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:92:in `require': cannot load such file -- rdoc (LoadError)
```

https://github.com/ruby/irb/commit/a2d299c2ac

* [ruby/irb] Suppress verbose messages in the parallel test

`:VERBOSE` flag needs to be set prior to `IRB::Irb.new`.

https://github.com/ruby/irb/commit/78604682d9

* [ruby/irb] SIGINT should raise Interrupt after IRB session

https://github.com/ruby/irb/commit/5832cfe75b

* [ruby/irb] Colorize `__END__` as keyword

https://github.com/ruby/irb/commit/9b84018311

* [ruby/irb] Add show_source command

https://github.com/ruby/irb/commit/108cb04352

* [ruby/reline] Reset @rest_height when clear screen

https://github.com/ruby/reline/commit/3a7019b0d5

* [ruby/irb] process multi-line pastes as a single entity

this allows pasting leading-dot chained methods correctly:

```ruby
class A
  def a; self; end
  def b; true; end
end

a = A.new

a
 .a
 .b
```

will properly return `true` instead of erroring on the `.a` line:

```
irb(main):001:1*     class A
irb(main):002:1*       def a; self; end
irb(main):003:0>     end
irb(main):004:0*
irb(main):005:0>     a = A.new
irb(main):006:0*
irb(main):007:0>     a
irb(main):008:0>      .a
irb(main):009:0>      .a
=> #<A:0x00007f984211fbe8>
```

https://github.com/ruby/irb/commit/45aeb52575

* [ruby/irb] Add yamatanooroti test example

https://github.com/ruby/irb/commit/279155fcee

* [ruby/irb] Add test for multiline paste

https://github.com/ruby/irb/commit/e93c9cb54d

* [ruby/irb] Evaluate each toplevel statement

https://github.com/ruby/irb/commit/bc1b1d8bc3

* [ruby/irb] Version 1.3.5

https://github.com/ruby/irb/commit/22e2ddf715

* [ruby/reline] Version 0.2.5

https://github.com/ruby/reline/commit/22ce5651e5

Co-authored-by: Jeremy Evans <code@jeremyevans.net>
Co-authored-by: Kazuhiro NISHIYAMA <zn@mbf.nifty.com>
Co-authored-by: Takashi Kokubun <takashikkbn@gmail.com>
Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>
Co-authored-by: Aleksandar Ivanov <aivanov92@gmail.com>
Co-authored-by: Koichi Sasada <ko1@atdot.net>
Co-authored-by: Cody Cutrer <cody@instructure.com>

18 files changed, 496 insertions, 101 deletions

diff --git a/lib/irb.rb b/lib/irb.rb
index 7f99974f28..93c4d25c92 100644
--- a/lib/irb.rb
+++ b/lib/irb.rb
@@ -60,7 +60,11 @@ require_relative "irb/easter-egg"
 #     -E enc            Same as `ruby -E`
 #     -w                Same as `ruby -w`
 #     -W[level=2]       Same as `ruby -W`
-#     --inspect         Use `inspect' for output (default except for bc mode)
+#     --context-mode n  Set n[0-4] to method to create Binding Object,
+#                       when new workspace was created
+#     --echo            Show result(default)
+#     --noecho          Don't show result
+#     --inspect         Use `inspect' for output
 #     --noinspect       Don't use inspect for output
 #     --multiline       Use multiline editor module
 #     --nomultiline     Don't use multiline editor module
@@ -68,19 +72,24 @@ require_relative "irb/easter-egg"
 #     --nosingleline    Don't use singleline editor module
 #     --colorize        Use colorization
 #     --nocolorize      Don't use colorization
-#     --prompt prompt-mode
-#     --prompt-mode prompt-mode
+#     --prompt prompt-mode/--prompt-mode prompt-mode
 #                       Switch prompt mode. Pre-defined prompt modes are
 #                       `default', `simple', `xmp' and `inf-ruby'
 #     --inf-ruby-mode   Use prompt appropriate for inf-ruby-mode on emacs.
 #                       Suppresses --multiline and --singleline.
-#     --simple-prompt   Simple prompt mode
+#     --sample-book-mode/--simple-prompt
+#                       Simple prompt mode
 #     --noprompt        No prompt mode
+#     --single-irb      Share self with sub-irb.
 #     --tracer          Display trace for each execution of commands.
 #     --back-trace-limit n
 #                       Display backtrace top n and tail n. The default
 #                       value is 16.
-#     -v, --version     Print the version of irb
+#     --verbose         Show details
+#     --noverbose       Don't show details
+#     -v, --version	    Print the version of irb
+#     -h, --help        Print help
+#     --                Separate options of irb from the list of command-line args
 #
 # == Configuration
 #
@@ -463,7 +472,7 @@ module IRB
       conf[:IRB_RC].call(context) if conf[:IRB_RC]
       conf[:MAIN_CONTEXT] = context
 
-      trap("SIGINT") do
+      prev_trap = trap("SIGINT") do
         signal_handle
       end
 
@@ -472,6 +481,7 @@ module IRB
           eval_input
         end
       ensure
+        trap("SIGINT", prev_trap)
         conf[:AT_EXIT].each{|hook| hook.call}
       end
     end
diff --git a/lib/irb/cmd/ls.rb b/lib/irb/cmd/ls.rb
new file mode 100644
index 0000000000..f163f4f9e6
--- /dev/null
+++ b/lib/irb/cmd/ls.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require "reline"
+require_relative "nop"
+require_relative "../color"
+
+# :stopdoc:
+module IRB
+  module ExtendCommand
+    class Ls < Nop
+      def execute(*arg, grep: nil)
+        o = Output.new(grep: grep)
+
+        obj    = arg.empty? ? irb_context.workspace.main : arg.first
+        locals = arg.empty? ? irb_context.workspace.binding.local_variables : []
+        klass  = (obj.class == Class || obj.class == Module ? obj : obj.class)
+
+        o.dump("constants", obj.constants) if obj.respond_to?(:constants)
+        o.dump("#{klass}.methods", obj.singleton_methods(false))
+        o.dump("#{klass}#methods", klass.public_instance_methods(false))
+        o.dump("instance variables", obj.instance_variables)
+        o.dump("class variables", klass.class_variables)
+        o.dump("locals", locals)
+      end
+
+      class Output
+        MARGIN = "  "
+
+        def initialize(grep: nil)
+          @grep = grep
+          @line_width = screen_width - MARGIN.length # right padding
+        end
+
+        def dump(name, strs)
+          strs = strs.grep(@grep) if @grep
+          strs = strs.sort
+          return if strs.empty?
+
+          # Attempt a single line
+          print "#{Color.colorize(name, [:BOLD, :BLUE])}: "
+          if fits_on_line?(strs, cols: strs.size, offset: "#{name}: ".length)
+            puts strs.join(MARGIN)
+            return
+          end
+          puts
+
+          # Dump with the largest # of columns that fits on a line
+          cols = strs.size
+          until fits_on_line?(strs, cols: cols, offset: MARGIN.length) || cols == 1
+            cols -= 1
+          end
+          widths = col_widths(strs, cols: cols)
+          strs.each_slice(cols) do |ss|
+            puts ss.map.with_index { |s, i| "#{MARGIN}%-#{widths[i]}s" % s }.join
+          end
+        end
+
+        private
+
+        def fits_on_line?(strs, cols:, offset: 0)
+          width = col_widths(strs, cols: cols).sum + MARGIN.length * (cols - 1)
+          width <= @line_width - offset
+        end
+
+        def col_widths(strs, cols:)
+          cols.times.map do |col|
+            (col...strs.size).step(cols).map do |i|
+              strs[i].length
+            end.max
+          end
+        end
+
+        def screen_width
+          Reline.get_screen_size.last
+        rescue Errno::EINVAL # in `winsize': Invalid argument - <STDIN>
+          80
+        end
+      end
+      private_constant :Output
+    end
+  end
+end
+# :startdoc:
diff --git a/lib/irb/cmd/nop.rb b/lib/irb/cmd/nop.rb
index fa3c011b5f..d6f7a611a6 100644
--- a/lib/irb/cmd/nop.rb
+++ b/lib/irb/cmd/nop.rb
@@ -14,10 +14,16 @@ module IRB
   module ExtendCommand
     class Nop
 
-
-      def self.execute(conf, *opts, &block)
-        command = new(conf)
-        command.execute(*opts, &block)
+      if RUBY_ENGINE == "ruby" && RUBY_VERSION >= "2.7.0"
+        def self.execute(conf, *opts, **kwargs, &block)
+          command = new(conf)
+          command.execute(*opts, **kwargs, &block)
+        end
+      else
+        def self.execute(conf, *opts, &block)
+          command = new(conf)
+          command.execute(*opts, &block)
+        end
       end
 
       def initialize(conf)
diff --git a/lib/irb/cmd/show_source.rb b/lib/irb/cmd/show_source.rb
new file mode 100644
index 0000000000..0bd40b7d4e
--- /dev/null
+++ b/lib/irb/cmd/show_source.rb
@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+require_relative "nop"
+require_relative "../color"
+require_relative "../ruby-lex"
+
+# :stopdoc:
+module IRB
+  module ExtendCommand
+    class ShowSource < Nop
+      def execute(str = nil)
+        unless str.is_a?(String)
+          puts "Error: Expected a string but got #{str.inspect}"
+          return
+        end
+        source = find_source(str)
+        if source && File.exist?(source.file)
+          show_source(source)
+        else
+          puts "Error: Couldn't locate a definition for #{str}"
+        end
+        nil
+      end
+
+      private
+
+      # @param [IRB::ExtendCommand::ShowSource::Source] source
+      def show_source(source)
+        puts
+        puts "#{bold("From")}: #{source.file}:#{source.first_line}"
+        puts
+        code = IRB::Color.colorize_code(File.read(source.file))
+        puts code.lines[(source.first_line - 1)...source.last_line].join
+        puts
+      end
+
+      def find_source(str)
+        case str
+        when /\A[A-Z]\w*(::[A-Z]\w*)*\z/ # Const::Name
+          eval(str, irb_context.workspace.binding) # trigger autoload
+          base = irb_context.workspace.binding.receiver.yield_self { |r| r.is_a?(Module) ? r : Object }
+          file, line = base.const_source_location(str) if base.respond_to?(:const_source_location) # Ruby 2.7+
+        when /\A(?<owner>[A-Z]\w*(::[A-Z]\w*)*)#(?<method>[^ :.]+)\z/ # Class#method
+          owner = eval(Regexp.last_match[:owner], irb_context.workspace.binding)
+          method = Regexp.last_match[:method]
+          if owner.respond_to?(:instance_method) && owner.instance_methods.include?(method.to_sym)
+            file, line = owner.instance_method(method).source_location
+          end
+        when /\A((?<receiver>.+)(\.|::))?(?<method>[^ :.]+)\z/ # method, receiver.method, receiver::method
+          receiver = eval(Regexp.last_match[:receiver] || 'self', irb_context.workspace.binding)
+          method = Regexp.last_match[:method]
+          file, line = receiver.method(method).source_location if receiver.respond_to?(method)
+        end
+        if file && line
+          Source.new(file: file, first_line: line, last_line: find_end(file, line))
+        end
+      end
+
+      def find_end(file, first_line)
+        return first_line unless File.exist?(file)
+        lex = RubyLex.new
+        code = +""
+        File.read(file).lines[(first_line - 1)..-1].each_with_index do |line, i|
+          _ltype, _indent, continue, code_block_open = lex.check_state(code << line)
+          if !continue && !code_block_open
+            return first_line + i
+          end
+        end
+        first_line
+      end
+
+      def bold(str)
+        Color.colorize(str, [:BOLD])
+      end
+
+      Source = Struct.new(
+        :file,       # @param [String] - file name
+        :first_line, # @param [String] - first line
+        :last_line,  # @param [String] - last line
+        keyword_init: true,
+      )
+      private_constant :Source
+    end
+  end
+end
+# :startdoc:
diff --git a/lib/irb/cmd/whereami.rb b/lib/irb/cmd/whereami.rb
new file mode 100644
index 0000000000..b3def11b93
--- /dev/null
+++ b/lib/irb/cmd/whereami.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require_relative "nop"
+
+# :stopdoc:
+module IRB
+  module ExtendCommand
+    class Whereami < Nop
+      def execute(*)
+        code = irb_context.workspace.code_around_binding
+        if code
+          puts code
+        else
+          puts "The current context doesn't have code."
+        end
+      end
+    end
+  end
+end
+# :startdoc:
diff --git a/lib/irb/color.rb b/lib/irb/color.rb
index a054bb20f8..cfbb3cc668 100644
--- a/lib/irb/color.rb
+++ b/lib/irb/color.rb
@@ -64,6 +64,7 @@ module IRB # :nodoc:
         on_alias_error:     [[RED, REVERSE],          ALL],
         on_class_name_error:[[RED, REVERSE],          ALL],
         on_param_error:     [[RED, REVERSE],          ALL],
+        on___end__:         [[GREEN],                 ALL],
       }
     rescue NameError
       # Give up highlighting Ripper-incompatible older Ruby
@@ -120,6 +121,7 @@ module IRB # :nodoc:
         symbol_state = SymbolState.new
         colored = +''
         length = 0
+        end_seen = false
 
         scan(code, allow_last_error: !complete) do |token, str, expr|
           # IRB::ColorPrinter skips colorizing fragments with any invalid token
@@ -138,10 +140,11 @@ module IRB # :nodoc:
             end
           end
           length += str.bytesize
+          end_seen = true if token == :on___end__
         end
 
         # give up colorizing incomplete Ripper tokens
-        if length != code.bytesize
+        unless end_seen or length == code.bytesize
           return Reline::Unicode.escape_for_print(code)
         end
 
diff --git a/lib/irb/color_printer.rb b/lib/irb/color_printer.rb
index 92afea51cd..30c6825750 100644
--- a/lib/irb/color_printer.rb
+++ b/lib/irb/color_printer.rb
@@ -21,6 +21,15 @@ module IRB
       end
     end
 
+    def pp(obj)
+      if obj.is_a?(String)
+        # Avoid calling Ruby 2.4+ String#pretty_print that splits a string by "\n"
+        text(obj.inspect)
+      else
+        super
+      end
+    end
+
     def text(str, width = nil)
       unless str.is_a?(String)
         str = str.inspect
diff --git a/lib/irb/completion.rb b/lib/irb/completion.rb
index 22a1ad1d3d..d1bb82122e 100644
--- a/lib/irb/completion.rb
+++ b/lib/irb/completion.rb
@@ -7,7 +7,7 @@
 #       From Original Idea of shugo@ruby-lang.org
 #
 
-autoload :RDoc, "rdoc"
+require_relative 'ruby-lex'
 
 module IRB
   module InputCompletor # :nodoc:
@@ -38,8 +38,69 @@ module IRB
 
     BASIC_WORD_BREAK_CHARACTERS = " \t\n`><=;|&{("
 
-    CompletionProc = proc { |input|
-      retrieve_completion_data(input).compact.map{ |i| i.encode(Encoding.default_external) }
+    def self.retrieve_files_to_require_from_load_path
+      @@files_from_load_path ||= $LOAD_PATH.flat_map { |path|
+        begin
+          Dir.glob("**/*.{rb,#{RbConfig::CONFIG['DLEXT']}}", base: path)
+        rescue Errno::ENOENT
+          []
+        end
+      }.uniq.map { |path|
+        path.sub(/\.(rb|#{RbConfig::CONFIG['DLEXT']})\z/, '')
+      }
+    end
+
+    def self.retrieve_files_to_require_relative_from_current_dir
+      @@files_from_current_dir ||= Dir.glob("**/*.{rb,#{RbConfig::CONFIG['DLEXT']}}", base: '.').map { |path|
+        path.sub(/\.(rb|#{RbConfig::CONFIG['DLEXT']})\z/, '')
+      }
+    end
+
+    CompletionRequireProc = lambda { |target, preposing = nil, postposing = nil|
+      if target =~ /\A(['"])([^'"]+)\Z/
+        quote = $1
+        actual_target = $2
+      else
+        return nil # It's not String literal
+      end
+      tokens = RubyLex.ripper_lex_without_warning(preposing.gsub(/\s*\z/, ''))
+      tok = nil
+      tokens.reverse_each do |t|
+        unless [:on_lparen, :on_sp, :on_ignored_sp, :on_nl, :on_ignored_nl, :on_comment].include?(t.event)
+          tok = t
+          break
+        end
+      end
+      result = []
+      if tok && tok.event == :on_ident && tok.state == Ripper::EXPR_CMDARG
+        case tok.tok
+        when 'require'
+          result = retrieve_files_to_require_from_load_path.select { |path|
+            path.start_with?(actual_target)
+          }.map { |path|
+            quote + path
+          }
+        when 'require_relative'
+          result = retrieve_files_to_require_relative_from_current_dir.select { |path|
+            path.start_with?(actual_target)
+          }.map { |path|
+            quote + path
+          }
+        end
+      end
+      result
+    }
+
+    CompletionProc = lambda { |target, preposing = nil, postposing = nil|
+      if preposing && postposing
+        result = CompletionRequireProc.(target, preposing, postposing)
+        unless result
+          result = retrieve_completion_data(target).compact.map{ |i| i.encode(Encoding.default_external) }
+        end
+        result
+      else
+        retrieve_completion_data(target).compact.map{ |i| i.encode(Encoding.default_external) }
+      end
     }
 
     def self.retrieve_completion_data(input, bind: IRB.conf[:MAIN_CONTEXT].workspace.binding, doc_namespace: false)
@@ -266,13 +327,22 @@ module IRB
     end
 
     PerfectMatchedProc = ->(matched, bind: IRB.conf[:MAIN_CONTEXT].workspace.binding) {
+      begin
+        require 'rdoc'
+      rescue LoadError
+        return
+      end
+
       RDocRIDriver ||= RDoc::RI::Driver.new
+
       if matched =~ /\A(?:::)?RubyVM/ and not ENV['RUBY_YES_I_AM_NOT_A_NORMAL_USER']
         IRB.__send__(:easter_egg)
         return
       end
+
       namespace = retrieve_completion_data(matched, bind: bind, doc_namespace: true)
       return unless namespace
+
       if namespace.is_a?(Array)
         out = RDoc::Markup::Document.new
         namespace.each do |m|
diff --git a/lib/irb/ext/save-history.rb b/lib/irb/ext/save-history.rb
index ac358c8ccb..7acaebe36a 100644
--- a/lib/irb/ext/save-history.rb
+++ b/lib/irb/ext/save-history.rb
@@ -81,6 +81,8 @@ module IRB
             end
           }
         end
+        @loaded_history_lines = history.size
+        @loaded_history_mtime = File.mtime(history_file)
       end
     end
 
@@ -105,12 +107,20 @@ module IRB
           raise
         end
 
-        open(history_file, "w:#{IRB.conf[:LC_MESSAGES].encoding}", 0600) do |f|
+        if File.exist?(history_file) && @loaded_history_mtime &&
+           File.mtime(history_file) != @loaded_history_mtime
+          history = history[@loaded_history_lines..-1]
+          append_history = true
+        end
+
+        open(history_file, "#{append_history ? 'a' : 'w'}:#{IRB.conf[:LC_MESSAGES].encoding}", 0600) do |f|
           hist = history.map{ |l| l.split("\n").join("\\\n") }
-          begin
-            hist = hist.last(num) if hist.size > num and num > 0
-          rescue RangeError # bignum too big to convert into `long'
-            # Do nothing because the bignum should be treated as inifinity
+          unless append_history
+            begin
+              hist = hist.last(num) if hist.size > num and num > 0
+            rescue RangeError # bignum too big to convert into `long'
+              # Do nothing because the bignum should be treated as inifinity
+            end
           end
           f.puts(hist)
         end
diff --git a/lib/irb/extend-command.rb b/lib/irb/extend-command.rb
index 347323247e..339e9e6084 100644
--- a/lib/irb/extend-command.rb
+++ b/lib/irb/extend-command.rb
@@ -126,7 +126,23 @@ module IRB # :nodoc:
       ],
 
       [
-        :measure, :Measure, "irb/cmd/measure"
+        :irb_ls, :Ls, "irb/cmd/ls",
+        [:ls, NO_OVERRIDE],
+      ],
+
+      [
+        :irb_measure, :Measure, "irb/cmd/measure",
+        [:measure, NO_OVERRIDE],
+      ],
+
+      [
+        :irb_show_source, :ShowSource, "irb/cmd/show_source",
+        [:show_source, NO_OVERRIDE],
+      ],
+
+      [
+        :irb_whereami, :Whereami, "irb/cmd/whereami",
+        [:whereami, NO_OVERRIDE],
       ],
 
     ]
@@ -168,12 +184,13 @@ module IRB # :nodoc:
       end
 
       if load_file
+        kwargs = ", **kwargs" if RUBY_ENGINE == "ruby" && RUBY_VERSION >= "2.7.0"
         line = __LINE__; eval %[
-          def #{cmd_name}(*opts, &b)
+          def #{cmd_name}(*opts#{kwargs}, &b)
             require "#{load_file}"
             arity = ExtendCommand::#{cmd_class}.instance_method(:execute).arity
             args = (1..(arity < 0 ? ~arity : arity)).map {|i| "arg" + i.to_s }
-            args << "*opts" if arity < 0
+            args << "*opts#{kwargs}" if arity < 0
             args << "&block"
             args = args.join(", ")
             line = __LINE__; eval %[
@@ -184,7 +201,7 @@ module IRB # :nodoc:
                 end
               end
             ], nil, __FILE__, line
-            __send__ :#{cmd_name}_, *opts, &b
+            __send__ :#{cmd_name}_, *opts#{kwargs}, &b
           end
         ], nil, __FILE__, line
       else
diff --git a/lib/irb/input-method.rb b/lib/irb/input-method.rb
index e223672985..1854567a2d 100644
--- a/lib/irb/input-method.rb
+++ b/lib/irb/input-method.rb
@@ -280,6 +280,7 @@ module IRB
         Reline.basic_word_break_characters = IRB::InputCompletor::BASIC_WORD_BREAK_CHARACTERS
       end
       Reline.completion_append_character = nil
+      Reline.completer_quote_characters = ''
       Reline.completion_proc = IRB::InputCompletor::CompletionProc
       Reline.output_modifier_proc =
         if IRB.conf[:USE_COLORIZE]
diff --git a/lib/irb/irb.gemspec b/lib/irb/irb.gemspec
index 9842b4bce1..38fee9d9fb 100644
--- a/lib/irb/irb.gemspec
+++ b/lib/irb/irb.gemspec
@@ -28,53 +28,8 @@ Gem::Specification.new do |spec|
     "doc/irb/irb.rd.ja",
     "exe/irb",
     "irb.gemspec",
-    "lib/irb.rb",
-    "lib/irb/cmd/chws.rb",
-    "lib/irb/cmd/fork.rb",
-    "lib/irb/cmd/help.rb",
-    "lib/irb/cmd/info.rb",
-    "lib/irb/cmd/load.rb",
-    "lib/irb/cmd/measure.rb",
-    "lib/irb/cmd/nop.rb",
-    "lib/irb/cmd/pushws.rb",
-    "lib/irb/cmd/subirb.rb",
-    "lib/irb/color.rb",
-    "lib/irb/color_printer.rb",
-    "lib/irb/completion.rb",
-    "lib/irb/context.rb",
-    "lib/irb/easter-egg.rb",
-    "lib/irb/ext/change-ws.rb",
-    "lib/irb/ext/history.rb",
-    "lib/irb/ext/loader.rb",
-    "lib/irb/ext/multi-irb.rb",
-    "lib/irb/ext/save-history.rb",
-    "lib/irb/ext/tracer.rb",
-    "lib/irb/ext/use-loader.rb",
-    "lib/irb/ext/workspaces.rb",
-    "lib/irb/extend-command.rb",
-    "lib/irb/frame.rb",
-    "lib/irb/help.rb",
-    "lib/irb/init.rb",
-    "lib/irb/input-method.rb",
-    "lib/irb/inspector.rb",
-    "lib/irb/lc/error.rb",
-    "lib/irb/lc/help-message",
-    "lib/irb/lc/ja/encoding_aliases.rb",
-    "lib/irb/lc/ja/error.rb",
-    "lib/irb/lc/ja/help-message",
-    "lib/irb/locale.rb",
-    "lib/irb/magic-file.rb",
-    "lib/irb/notifier.rb",
-    "lib/irb/output-method.rb",
-    "lib/irb/ruby-lex.rb",
-    "lib/irb/ruby_logo.aa",
-    "lib/irb/src_encoding.rb",
-    "lib/irb/version.rb",
-    "lib/irb/workspace.rb",
-    "lib/irb/ws-for-case-2.rb",
-    "lib/irb/xmp.rb",
     "man/irb.1",
-  ]
+  ] + Dir.glob("lib/**/*")
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
diff --git a/lib/irb/lc/help-message b/lib/irb/lc/help-message
index a80facc9c5..9c3ea859ad 100644
--- a/lib/irb/lc/help-message
+++ b/lib/irb/lc/help-message
@@ -10,7 +10,7 @@
 #
 #
 Usage:  irb.rb [options] [programfile] [arguments]
-  -f		    Suppress read of ~/.irbrc
+  -f                Suppress read of ~/.irbrc
   -d                Set $DEBUG to true (same as `ruby -d')
   -r load-module    Same as `ruby -r'
   -I path           Specify $LOAD_PATH directory
@@ -18,7 +18,7 @@ Usage:  irb.rb [options] [programfile] [arguments]
   -E enc            Same as `ruby -E`
   -w                Same as `ruby -w`
   -W[level=2]       Same as `ruby -W`
-  --context-mode n  Set n[0-3] to method to create Binding Object,
+  --context-mode n  Set n[0-4] to method to create Binding Object,
                     when new workspace was created
   --echo            Show result(default)
   --noecho          Don't show result
@@ -31,8 +31,8 @@ Usage:  irb.rb [options] [programfile] [arguments]
   --colorize        Use colorization
   --nocolorize      Don't use colorization
   --prompt prompt-mode/--prompt-mode prompt-mode
-		    Switch prompt mode. Pre-defined prompt modes are
-		    `default', `simple', `xmp' and `inf-ruby'
+                    Switch prompt mode. Pre-defined prompt modes are
+                    `default', `simple', `xmp' and `inf-ruby'
   --inf-ruby-mode   Use prompt appropriate for inf-ruby-mode on emacs.
                     Suppresses --multiline and --singleline.
   --sample-book-mode/--simple-prompt
@@ -41,8 +41,8 @@ Usage:  irb.rb [options] [programfile] [arguments]
   --single-irb      Share self with sub-irb.
   --tracer          Display trace for each execution of commands.
   --back-trace-limit n
-		    Display backtrace top n and tail n. The default
-		    value is 16.
+                    Display backtrace top n and tail n. The default
+                    value is 16.
   --verbose         Show details
   --noverbose       Don't show details
   -v, --version	    Print the version of irb
diff --git a/lib/irb/ruby-lex.rb b/lib/irb/ruby-lex.rb
index ce94797dad..82df06da2b 100644
--- a/lib/irb/ruby-lex.rb
+++ b/lib/irb/ruby-lex.rb
@@ -47,12 +47,26 @@ class RubyLex
     @io = io
     if @io.respond_to?(:check_termination)
       @io.check_termination do |code|
-        code.gsub!(/\s*\z/, '').concat("\n")
-        ltype, indent, continue, code_block_open = check_state(code)
-        if ltype or indent > 0 or continue or code_block_open
-          false
+        if Reline::IOGate.in_pasting?
+          lex = RubyLex.new
+          rest = lex.check_termination_in_prev_line(code)
+          if rest
+            Reline.delete_text
+            rest.bytes.reverse_each do |c|
+              Reline.ungetc(c)
+            end
+            true
+          else
+            false
+          end
         else
-          true
+          code.gsub!(/\s*\z/, '').concat("\n")
+          ltype, indent, continue, code_block_open = check_state(code)
+          if ltype or indent > 0 or continue or code_block_open
+            false
+          else
+            true
+          end
         end
       end
     end
@@ -60,7 +74,7 @@ class RubyLex
       @io.dynamic_prompt do |lines|
         lines << '' if lines.empty?
         result = []
-        tokens = ripper_lex_without_warning(lines.map{ |l| l + "\n" }.join)
+        tokens = self.class.ripper_lex_without_warning(lines.map{ |l| l + "\n" }.join)
         code = String.new
         partial_tokens = []
         unprocessed_tokens = []
@@ -115,10 +129,10 @@ class RubyLex
     :on_param_error
   ]
 
-  def ripper_lex_without_warning(code)
+  def self.ripper_lex_without_warning(code)
     verbose, $VERBOSE = $VERBOSE, nil
     tokens = nil
-    self.class.compile_with_errors_suppressed(code) do |inner_code, line_no|
+    compile_with_errors_suppressed(code) do |inner_code, line_no|
       lexer = Ripper::Lexer.new(inner_code, '-', line_no)
       if lexer.respond_to?(:scan) # Ruby 2.7+
         tokens = []
@@ -168,7 +182,7 @@ class RubyLex
     if @io.respond_to?(:auto_indent) and context.auto_indent_mode
       @io.auto_indent do |lines, line_index, byte_pointer, is_newline|
         if is_newline
-          @tokens = ripper_lex_without_warning(lines[0..line_index].join("\n"))
+          @tokens = self.class.ripper_lex_without_warning(lines[0..line_index].join("\n"))
           prev_spaces = find_prev_spaces(line_index)
           depth_difference = check_newline_depth_difference
           depth_difference = 0 if depth_difference < 0
@@ -177,7 +191,7 @@ class RubyLex
           code = line_index.zero? ? '' : lines[0..(line_index - 1)].map{ |l| l + "\n" }.join
           last_line = lines[line_index]&.byteslice(0, byte_pointer)
           code += last_line if last_line
-          @tokens = ripper_lex_without_warning(code)
+          @tokens = self.class.ripper_lex_without_warning(code)
           corresponding_token_depth = check_corresponding_token_depth
           if corresponding_token_depth
             corresponding_token_depth
@@ -190,7 +204,7 @@ class RubyLex
   end
 
   def check_state(code, tokens = nil)
-    tokens = ripper_lex_without_warning(code) unless tokens
+    tokens = self.class.ripper_lex_without_warning(code) unless tokens
     ltype = process_literal_type(tokens)
     indent = process_nesting_level(tokens)
     continue = process_continue(tokens)
@@ -256,7 +270,7 @@ class RubyLex
     end
     code = @line + (line.nil? ? '' : line)
     code.gsub!(/\s*\z/, '').concat("\n")
-    @tokens = ripper_lex_without_warning(code)
+    @tokens = self.class.ripper_lex_without_warning(code)
     @continue = process_continue
     @code_block_open = check_code_block(code)
     @indent = process_nesting_level
@@ -277,8 +291,9 @@ class RubyLex
       return true
     elsif tokens.size >= 1 and tokens[-1][1] == :on_heredoc_end # "EOH\n"
       return false
-    elsif tokens.size >= 2 and defined?(Ripper::EXPR_BEG) and tokens[-2][3].anybits?(Ripper::EXPR_BEG | Ripper::EXPR_FNAME)
+    elsif tokens.size >= 2 and defined?(Ripper::EXPR_BEG) and tokens[-2][3].anybits?(Ripper::EXPR_BEG | Ripper::EXPR_FNAME) and tokens[-2][2] !~ /\A\.\.\.?\z/
       # end of literal except for regexp
+      # endless range at end of line is not a continue
       return true
     end
     false
@@ -738,5 +753,50 @@ class RubyLex
       nil
     end
   end
+
+  def check_termination_in_prev_line(code)
+    tokens = self.class.ripper_lex_without_warning(code)
+    past_first_newline = false
+    index = tokens.rindex do |t|
+      # traverse first token before last line
+      if past_first_newline
+        if t.tok.include?("\n")
+          true
+        end
+      elsif t.tok.include?("\n")
+        past_first_newline = true
+        false
+      else
+        false
+      end
+    end
+    if index
+      first_token = nil
+      last_line_tokens = tokens[(index + 1)..(tokens.size - 1)]
+      last_line_tokens.each do |t|
+        unless [:on_sp, :on_ignored_sp, :on_comment].include?(t.event)
+          first_token = t
+          break
+        end
+      end
+      if first_token.nil?
+        return false
+      elsif first_token && first_token.state == Ripper::EXPR_DOT
+        return false
+      else
+        tokens_without_last_line = tokens[0..index]
+        ltype = process_literal_type(tokens_without_last_line)
+        indent = process_nesting_level(tokens_without_last_line)
+        continue = process_continue(tokens_without_last_line)
+        code_block_open = check_code_block(tokens_without_last_line.map(&:tok).join(''), tokens_without_last_line)
+        if ltype or indent > 0 or continue or code_block_open
+          return false
+        else
+          return last_line_tokens.map(&:tok).join('')
+        end
+      end
+    end
+    false
+  end
 end
 # :startdoc:
diff --git a/lib/irb/version.rb b/lib/irb/version.rb
index 0a4a1bb922..0014bdda74 100644
--- a/lib/irb/version.rb
+++ b/lib/irb/version.rb
@@ -11,7 +11,7 @@
 #
 
 module IRB # :nodoc:
-  VERSION = "1.3.4"
+  VERSION = "1.3.5"
   @RELEASE_VERSION = VERSION
-  @LAST_UPDATE_DATE = "2021-02-25"
+  @LAST_UPDATE_DATE = "2021-04-03"
 end
diff --git a/lib/reline.rb b/lib/reline.rb
index 81ea9f9b58..a7bd4d9280 100644
--- a/lib/reline.rb
+++ b/lib/reline.rb
@@ -446,6 +446,10 @@ module Reline
     }
   end
 
+  def self.ungetc(c)
+    Reline::IOGate.ungetc(c)
+  end
+
   def self.line_editor
     core.line_editor
   end
diff --git a/lib/reline/line_editor.rb b/lib/reline/line_editor.rb
index 12a2bde234..7d71e62d63 100644
--- a/lib/reline/line_editor.rb
+++ b/lib/reline/line_editor.rb
@@ -813,6 +813,7 @@ class Reline::LineEditor
     end
     move_cursor_up(back)
     move_cursor_down(@first_line_started_from + @started_from)
+    @rest_height = (Reline::IOGate.get_screen_size.first - 1) - Reline::IOGate.cursor_pos.y
     Reline::IOGate.move_cursor_column((prompt_width + @cursor) % @screen_size.last)
   end
 
@@ -1158,8 +1159,25 @@ class Reline::LineEditor
 
   def call_completion_proc
     result = retrieve_completion_block(true)
-    slice = result[1]
-    result = @completion_proc.(slice) if @completion_proc and slice
+    preposing, target, postposing = result
+    if @completion_proc and target
+      argnum = @completion_proc.parameters.inject(0) { |result, item|
+        case item.first
+        when :req, :opt
+          result + 1
+        when :rest
+          break 3
+        end
+      }
+      case argnum
+      when 1
+        result = @completion_proc.(target)
+      when 2
+        result = @completion_proc.(target, preposing)
+      when 3..Float::INFINITY
+        result = @completion_proc.(target, preposing, postposing)
+      end
+    end
     Reline.core.instance_variable_set(:@completion_quote_character, nil)
     result
   end
@@ -1207,8 +1225,16 @@ class Reline::LineEditor
   end
 
   def retrieve_completion_block(set_completion_quote_character = false)
-    word_break_regexp = /\A[#{Regexp.escape(Reline.completer_word_break_characters)}]/
-    quote_characters_regexp = /\A[#{Regexp.escape(Reline.completer_quote_characters)}]/
+    if Reline.completer_word_break_characters.empty?
+      word_break_regexp = nil
+    else
+      word_break_regexp = /\A[#{Regexp.escape(Reline.completer_word_break_characters)}]/
+    end
+    if Reline.completer_quote_characters.empty?
+      quote_characters_regexp = nil
+    else
+      quote_characters_regexp = /\A[#{Regexp.escape(Reline.completer_quote_characters)}]/
+    end
     before = @line.byteslice(0, @byte_pointer)
     rest = nil
     break_pointer = nil
@@ -1229,14 +1255,14 @@ class Reline::LineEditor
       elsif quote and slice.start_with?(escaped_quote)
         # skip
         i += 2
-      elsif slice =~ quote_characters_regexp # find new "
+      elsif quote_characters_regexp and slice =~ quote_characters_regexp # find new "
         rest = $'
         quote = $&
         closing_quote = /(?!\\)#{Regexp.escape(quote)}/
         escaped_quote = /\\#{Regexp.escape(quote)}/
         i += 1
         break_pointer = i - 1
-      elsif not quote and slice =~ word_break_regexp
+      elsif word_break_regexp and not quote and slice =~ word_break_regexp
         rest = $'
         i += 1
         before = @line.byteslice(i, @byte_pointer - i)
@@ -1264,6 +1290,19 @@ class Reline::LineEditor
       end
       target = before
     end
+    if @is_multiline
+      if @previous_line_index
+        lines = whole_lines(index: @previous_line_index, line: @line)
+      else
+        lines = whole_lines
+      end
+      if @line_index > 0
+        preposing = lines[0..(@line_index - 1)].join("\n") + "\n" + preposing
+      end
+      if (lines.size - 1) > @line_index
+        postposing = postposing + "\n" + lines[(@line_index + 1)..-1].join("\n")
+      end
+    end
     [preposing.encode(@encoding), target.encode(@encoding), postposing.encode(@encoding)]
   end
 
@@ -1291,10 +1330,32 @@ class Reline::LineEditor
 
   def delete_text(start = nil, length = nil)
     if start.nil? and length.nil?
-      @line&.clear
-      @byte_pointer = 0
-      @cursor = 0
-      @cursor_max = 0
+      if @is_multiline
+        if @buffer_of_lines.size == 1
+          @line&.clear
+          @byte_pointer = 0
+          @cursor = 0
+          @cursor_max = 0
+        elsif @line_index == (@buffer_of_lines.size - 1) and @line_index > 0
+          @buffer_of_lines.pop
+          @line_index -= 1
+          @line = @buffer_of_lines[@line_index]
+          @byte_pointer = 0
+          @cursor = 0
+          @cursor_max = calculate_width(@line)
+        elsif @line_index < (@buffer_of_lines.size - 1)
+          @buffer_of_lines.delete_at(@line_index)
+          @line = @buffer_of_lines[@line_index]
+          @byte_pointer = 0
+          @cursor = 0
+          @cursor_max = calculate_width(@line)
+        end
+      else
+        @line&.clear
+        @byte_pointer = 0
+        @cursor = 0
+        @cursor_max = 0
+      end
     elsif not start.nil? and not length.nil?
       if @line
         before = @line.byteslice(0, start)
diff --git a/lib/reline/version.rb b/lib/reline/version.rb
index 11e8145c7f..44db465a2f 100644
--- a/lib/reline/version.rb
+++ b/lib/reline/version.rb
@@ -1,3 +1,3 @@
 module Reline
-  VERSION = '0.2.4'
+  VERSION = '0.2.5'
 end