♻️ Extract ParserUtils module

Author: nevans

lib/net/imap/response_parser.rb

@@ -1,12 +1,15 @@
 # frozen_string_literal: true
 
 require_relative "errors"
+require_relative "response_parser/parser_utils"
 
 module Net
   class IMAP < Protocol
 
     # Parses an \IMAP server response.
     class ResponseParser
+      include ParserUtils
+
       # :call-seq: Net::IMAP::ResponseParser.new -> Net::IMAP::ResponseParser
       def initialize
         @str = nil
@@ -1422,46 +1425,6 @@ def accept_spaces
         end
       end
 
-      def match(*args, lex_state: @lex_state)
-        if @token && lex_state != @lex_state
-          parse_error("invalid lex_state change to %s with unconsumed token",
-                      lex_state)
-        end
-        begin
-          @lex_state, original_lex_state = lex_state, @lex_state
-          token = lookahead
-          unless args.include?(token.symbol)
-            parse_error('unexpected token %s (expected %s)',
-                        token.symbol.id2name,
-                        args.collect {|i| i.id2name}.join(" or "))
-          end
-          shift_token
-          return token
-        ensure
-          @lex_state = original_lex_state
-        end
-      end
-
-      # like match, but does not raise error on failure.
-      #
-      # returns and shifts token on successful match
-      # returns nil and leaves @token unshifted on no match
-      def accept(*args)
-        token = lookahead
-        if args.include?(token.symbol)
-          shift_token
-          token
-        end
-      end
-
-      def lookahead
-        @token ||= next_token
-      end
-
-      def shift_token
-        @token = nil
-      end
-
       def next_token
         case @lex_state
         when EXPR_BEG

lib/net/imap/response_parser/parser_utils.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+module Net
+  class IMAP < Protocol
+    class ResponseParser
+      # basic utility methods for parsing.
+      #
+      # (internal API, subject to change)
+      module ParserUtils # :nodoc:
+
+        private
+
+        def match(*args, lex_state: @lex_state)
+          if @token && lex_state != @lex_state
+            parse_error("invalid lex_state change to %s with unconsumed token",
+                        lex_state)
+          end
+          begin
+            @lex_state, original_lex_state = lex_state, @lex_state
+            token = lookahead
+            unless args.include?(token.symbol)
+              parse_error('unexpected token %s (expected %s)',
+                          token.symbol.id2name,
+                          args.collect {|i| i.id2name}.join(" or "))
+            end
+            shift_token
+            return token
+          ensure
+            @lex_state = original_lex_state
+          end
+        end
+
+        # like match, but does not raise error on failure.
+        #
+        # returns and shifts token on successful match
+        # returns nil and leaves @token unshifted on no match
+        def accept(*args)
+          token = lookahead
+          if args.include?(token.symbol)
+            shift_token
+            token
+          end
+        end
+
+        def lookahead
+          @token ||= next_token
+        end
+
+        def shift_token
+          @token = nil
+        end
+      end
+    end
+  end
+end