Move IO configuration to IRB::Irb (#681)

It shouldn't be `RubyLex`'s responsibility to handle IO. So this moves
the configuration to `IRB::Irb`.

lib/irb.rb

@@ -537,7 +537,7 @@ def eval_input
         end
       end
 
-      @scanner.configure_io(@context.io)
+      configure_io
 
       @scanner.each_top_level_statement do |line, line_no, is_assignment|
         signal_status(:IN_EVAL) do
@@ -564,6 +564,58 @@ def eval_input
       end
     end
 
+    def configure_io
+      if @context.io.respond_to?(:check_termination)
+        @context.io.check_termination do |code|
+          if Reline::IOGate.in_pasting?
+            rest = @scanner.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
+            # Accept any single-line input for symbol aliases or commands that transform args
+            next true if @scanner.single_line_command?(code)
+
+            _tokens, _opens, terminated = @scanner.check_code_state(code)
+            terminated
+          end
+        end
+      end
+      if @context.io.respond_to?(:dynamic_prompt)
+        @context.io.dynamic_prompt do |lines|
+          lines << '' if lines.empty?
+          tokens = RubyLex.ripper_lex_without_warning(lines.map{ |l| l + "\n" }.join, context: @context)
+          line_results = IRB::NestingParser.parse_by_line(tokens)
+          tokens_until_line = []
+          line_results.map.with_index do |(line_tokens, _prev_opens, next_opens, _min_depth), line_num_offset|
+            line_tokens.each do |token, _s|
+              # Avoid appending duplicated token. Tokens that include "\n" like multiline tstring_content can exist in multiple lines.
+              tokens_until_line << token if token != tokens_until_line.last
+            end
+            continue = @scanner.should_continue?(tokens_until_line)
+            @scanner.prompt(next_opens, continue, line_num_offset)
+          end
+        end
+      end
+
+      if @context.io.respond_to?(:auto_indent) and @context.auto_indent_mode
+        @context.io.auto_indent do |lines, line_index, byte_pointer, is_newline|
+          next nil if lines == [nil] # Workaround for exit IRB with CTRL+d
+          next nil if !is_newline && lines[line_index]&.byteslice(0, byte_pointer)&.match?(/\A\s*\z/)
+
+          code = lines[0..line_index].map { |l| "#{l}\n" }.join
+          tokens = RubyLex.ripper_lex_without_warning(code, context: @context)
+          @scanner.process_indent_level(tokens, lines, line_index, is_newline)
+        end
+      end
+    end
+
     def evaluate_line(line, line_no)
       # Transform a non-identifier alias (@, $) or keywords (next, break)
       command, args = line.split(/\s/, 2)

lib/irb/ruby-lex.rb

@@ -74,59 +74,6 @@ def set_input(&block)
     @input = block
   end
 
-  def configure_io(io)
-    @io = io
-    if @io.respond_to?(:check_termination)
-      @io.check_termination do |code|
-        if Reline::IOGate.in_pasting?
-          rest = 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
-          # Accept any single-line input for symbol aliases or commands that transform args
-          next true if single_line_command?(code)
-
-          _tokens, _opens, terminated = check_code_state(code)
-          terminated
-        end
-      end
-    end
-    if @io.respond_to?(:dynamic_prompt)
-      @io.dynamic_prompt do |lines|
-        lines << '' if lines.empty?
-        tokens = self.class.ripper_lex_without_warning(lines.map{ |l| l + "\n" }.join, context: @context)
-        line_results = IRB::NestingParser.parse_by_line(tokens)
-        tokens_until_line = []
-        line_results.map.with_index do |(line_tokens, _prev_opens, next_opens, _min_depth), line_num_offset|
-          line_tokens.each do |token, _s|
-            # Avoid appending duplicated token. Tokens that include "\n" like multiline tstring_content can exist in multiple lines.
-            tokens_until_line << token if token != tokens_until_line.last
-          end
-          continue = should_continue?(tokens_until_line)
-          prompt(next_opens, continue, line_num_offset)
-        end
-      end
-    end
-
-    if @io.respond_to?(:auto_indent) and @context.auto_indent_mode
-      @io.auto_indent do |lines, line_index, byte_pointer, is_newline|
-        next nil if lines == [nil] # Workaround for exit IRB with CTRL+d
-        next nil if !is_newline && lines[line_index]&.byteslice(0, byte_pointer)&.match?(/\A\s*\z/)
-
-        code = lines[0..line_index].map { |l| "#{l}\n" }.join
-        tokens = self.class.ripper_lex_without_warning(code, context: @context)
-        process_indent_level(tokens, lines, line_index, is_newline)
-      end
-    end
-  end
-
   def set_prompt(&block)
     @prompt = block
   end
@@ -240,7 +187,7 @@ def readmultiline
     save_prompt_to_context_io([], false, 0)
 
     # multiline
-    return @input.call if @io.respond_to?(:check_termination)
+    return @input.call if @context.io.respond_to?(:check_termination)
 
     # nomultiline
     code = ''
@@ -270,7 +217,7 @@ def each_top_level_statement
       break unless code
 
       if code != "\n"
-        code.force_encoding(@io.encoding)
+        code.force_encoding(@context.io.encoding)
         yield code, @line_no, assignment_expression?(code)
       end
       @line_no += code.count("\n")