diff --git a/lib/phonelib/phone_analyzer.rb b/lib/phonelib/phone_analyzer.rb
index ded95ff..ff14624 100644
--- a/lib/phonelib/phone_analyzer.rb
+++ b/lib/phonelib/phone_analyzer.rb
@@ -139,7 +139,7 @@ def detect_and_parse(phone, country)
     end
 
     def country_code_candidates_for(phone)
-      stripped_phone = phone.gsub(/^(#{Phonelib.phone_data_int_prefixes})/, '')
+      stripped_phone = phone.gsub(cr("Phonelib.phone_data_int_prefixes") { /^(#{Phonelib.phone_data_int_prefixes})/ }, '')
       ((1..3).map { |length| phone[0, length] } + (1..3).map { |length| stripped_phone[0, length] }).uniq
     end
 
diff --git a/lib/phonelib/phone_analyzer_helper.rb b/lib/phonelib/phone_analyzer_helper.rb
index 2affe29..0eceb60 100644
--- a/lib/phonelib/phone_analyzer_helper.rb
+++ b/lib/phonelib/phone_analyzer_helper.rb
@@ -52,7 +52,7 @@ def country_prefix(country)
 
     # caches regular expression, reusing it for later lookups
     def cr(regexp)
-      Phonelib.phone_regexp_cache[regexp] ||= Regexp.new(regexp).freeze
+      Phonelib.phone_regexp_cache[regexp] ||= Regexp.new(block_given? ? yield(regexp) : regexp).freeze
     end
 
     # defines whether country can have double country prefix in number