implement globally configurable limiters

Author: Tom Lord

lib/regexp-examples/constants.rb

@@ -2,6 +2,28 @@
 module RegexpExamples
   # Configuration settings to limit the number/length of Regexp examples generated
   class ResultCountLimiters
+    class << self
+      attr_accessor :max_repeater_variance, :max_group_results, :max_results_limit
+      def with_configuration(max_repeater_variance: nil,
+                            max_group_results: nil,
+                            max_results_limit: nil)
+        original_vals = [
+          @max_repeater_variance,
+          @max_group_results,
+          @max_results_limit
+        ]
+
+        @max_repeater_variance = max_repeater_variance if max_repeater_variance
+        @max_group_results = max_group_results if max_group_results
+        @max_results_limit = max_results_limit if max_results_limit
+
+        result = yield
+
+        @max_repeater_variance, @max_group_results, @max_results_limit = *original_vals
+
+        result
+      end
+    end
     # The maximum variance for any given repeater, to prevent a huge/infinite number of
     # examples from being listed. For example, if @@max_repeater_variance = 2 then:
     # .* is equivalent to .{0,2}
@@ -10,28 +32,21 @@ class ResultCountLimiters
     # .{,3} is equivalent to .{0,2}
     # .{3,8} is equivalent to .{3,5}
     MAX_REPEATER_VARIANCE_DEFAULT = 2
+    @max_repeater_variance = MAX_REPEATER_VARIANCE_DEFAULT
 
     # Maximum number of characters returned from a char set, to reduce output spam
     # For example, if @@max_group_results = 5 then:
     # \d is equivalent to [01234]
     # \w is equivalent to [abcde]
     MAX_GROUP_RESULTS_DEFAULT = 5
+    @max_group_results = MAX_GROUP_RESULTS_DEFAULT
 
     # Maximum number of results to be generated, for Regexp#examples
     # This is to prevent the system "freezing" when given instructions like:
     # /[ab]{30}/.examples
     # (Which would attempt to generate 2**30 == 1073741824 examples!!!)
     MAX_RESULTS_LIMIT_DEFAULT = 10_000
-    class << self
-      attr_reader :max_repeater_variance, :max_group_results, :max_results_limit
-      def configure!(max_repeater_variance: nil,
-                     max_group_results: nil,
-                     max_results_limit: nil)
-        @max_repeater_variance = (max_repeater_variance || MAX_REPEATER_VARIANCE_DEFAULT)
-        @max_group_results = (max_group_results || MAX_GROUP_RESULTS_DEFAULT)
-        @max_results_limit = (max_results_limit || MAX_RESULTS_LIMIT_DEFAULT)
-      end
-    end
+    @max_results_limit = MAX_RESULTS_LIMIT_DEFAULT
   end
 
   def self.max_repeater_variance