Add RuntimeMacros module

RuntimeMacros `.def_node_matcher` and `.def_node_search` accept block
that will be evaluated within cop context to get pattern pattern.
It can be used to pattern match values from config because are available
only during runtime.

Author: sl4vr

lib/rubocop-rspec.rb

@@ -12,6 +12,7 @@
 require_relative 'rubocop/rspec/top_level_describe'
 require_relative 'rubocop/rspec/wording'
 require_relative 'rubocop/rspec/language'
+require_relative 'rubocop/rspec/language/runtime_macros'
 require_relative 'rubocop/rspec/language/node_pattern'
 require_relative 'rubocop/rspec/top_level_group'
 require_relative 'rubocop/rspec/concept'

lib/rubocop/cop/rspec/cop.rb

@@ -20,6 +20,7 @@ module RSpec
       class Cop < ::RuboCop::Cop::Cop
         include RuboCop::RSpec::Language
         include RuboCop::RSpec::Language::NodePattern
+        extend RuboCop::RSpec::Language::RuntimeMacros
 
         DEFAULT_CONFIGURATION =
           RuboCop::RSpec::CONFIG.fetch('AllCops').fetch('RSpec')

lib/rubocop/rspec/language/node_pattern.rb

@@ -6,6 +6,7 @@ module Language
       # Common node matchers used for matching against the rspec DSL
       module NodePattern
         extend RuboCop::NodePattern::Macros
+        extend RuntimeMacros
 
         def_node_matcher :example_group?, ExampleGroups::ALL.block_pattern
         def_node_matcher :shared_group?, SharedGroups::ALL.block_pattern

lib/rubocop/rspec/language/runtime_macros.rb

@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module RSpec
+    module Language
+      # RuntimeMacros `.def_node_matcher` and `.def_node_search` accept block
+      # that will be evaluated within cop context to get pattern pattern.
+      # It can be used to pattern match values from config because are available
+      # only during runtime.
+      module RuntimeMacros
+        def def_runtime_node_matcher(method_name, &pattern_block)
+          pattern_block_constant =
+            set_pattern_block_constant(method_name, pattern_block)
+
+          src = "def #{method_name}(node, *args, &block);" \
+                'pattern = RuboCop::NodePattern.new' \
+                "(instance_exec(&#{pattern_block_constant}));" \
+                'match = pattern.match(node, *args, &block);' \
+                "#{predicate_method?(method_name) ? '!match.nil?' : 'match'};" \
+                'end'
+
+          location = caller_locations(1, 1).first
+          class_eval(src, location.path, location.lineno)
+        end
+
+        def def_runtime_node_search(method_name, &pattern_block)
+          pattern_block_constant =
+            set_pattern_block_constant(method_name, pattern_block)
+          search_method = predicate_method?(method_name) ? ':any?' : ':select'
+
+          src = "def #{method_name}(node, *args, &block);" \
+                'pattern = RuboCop::NodePattern.new' \
+                "(instance_exec(&#{pattern_block_constant}));" \
+                "node.each_node.public_method(#{search_method})" \
+                '.call(&pattern.public_method(:match, *args, &block));end'
+
+          location = caller_locations(1, 1).first
+          class_eval(src, location.path, location.lineno)
+        end
+
+        protected
+
+        def set_pattern_block_constant(method_name, pattern_block)
+          pattern_block_constant =
+            "#{method_name.to_s.upcase.sub('?', '_PREDICATE')}_PATTERN_BLOCK"
+          const_set(pattern_block_constant, pattern_block)
+          pattern_block_constant
+        end
+
+        def predicate_method?(method_name)
+          method_name.to_s.end_with?('?')
+        end
+      end
+    end
+  end
+end