From 40e456f031065a63e418c0673c046a4b1a851c1f Mon Sep 17 00:00:00 2001
From: fatkodima <fatkodima123@gmail.com>
Date: Sun, 14 Jun 2020 15:36:50 +0300
Subject: [PATCH] Add `post_condition_loop?` and `loop?` for `Node`

---
 CHANGELOG.md                        |  2 ++
 lib/rubocop/ast/node.rb             | 10 ++++++++++
 spec/rubocop/ast/for_node_spec.rb   | 12 ++++++++++++
 spec/rubocop/ast/until_node_spec.rb | 28 ++++++++++++++++++++++++++++
 spec/rubocop/ast/while_node_spec.rb | 28 ++++++++++++++++++++++++++++
 5 files changed, 80 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 66822baa3..90844a784 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### New features
 
+* [#36](https://github.com/rubocop-hq/rubocop-ast/pull/36): Add `post_condition_loop?` and `loop?` for `Node`. ([@fatkodima][])
 * [#4](https://github.com/rubocop-hq/rubocop-ast/issues/4): Add `interpolation?` for `RegexpNode`. ([@tejasbubane][])
 * [#20](https://github.com/rubocop-hq/rubocop-ast/pull/20): Add option predicates for `RegexpNode`. ([@owst][])
 * [#11](https://github.com/rubocop-hq/rubocop-ast/issues/11): Add `argument_type?` method to make it easy to recognize argument nodes. ([@tejasbubane][])
@@ -32,3 +33,4 @@
 
 [@marcandre]: https://github.com/marcandre
 [@owst]: https://github.com/owst
+[@fatkodima]: https://github.com/fatkodima
diff --git a/lib/rubocop/ast/node.rb b/lib/rubocop/ast/node.rb
index 483ffc13f..bd1853bd9 100644
--- a/lib/rubocop/ast/node.rb
+++ b/lib/rubocop/ast/node.rb
@@ -44,6 +44,8 @@ class Node < Parser::AST::Node # rubocop:disable Metrics/ClassLength
 
       BASIC_CONDITIONALS = %i[if while until].freeze
       CONDITIONALS = [*BASIC_CONDITIONALS, :case].freeze
+      POST_CONDITION_LOOP_TYPES = %i[while_post until_post].freeze
+      LOOP_TYPES = (POST_CONDITION_LOOP_TYPES + %i[while until for]).freeze
       VARIABLES = %i[ivar gvar cvar lvar].freeze
       REFERENCES = %i[nth_ref back_ref].freeze
       KEYWORDS = %i[alias and break case class def defs defined?
@@ -426,6 +428,14 @@ def conditional?
         CONDITIONALS.include?(type)
       end
 
+      def post_condition_loop?
+        POST_CONDITION_LOOP_TYPES.include?(type)
+      end
+
+      def loop?
+        LOOP_TYPES.include?(type)
+      end
+
       def keyword?
         return true if special_keyword? || send_type? && prefix_not?
         return false unless KEYWORDS.include?(type)
diff --git a/spec/rubocop/ast/for_node_spec.rb b/spec/rubocop/ast/for_node_spec.rb
index 94b84bb75..f41f794a8 100644
--- a/spec/rubocop/ast/for_node_spec.rb
+++ b/spec/rubocop/ast/for_node_spec.rb
@@ -60,4 +60,16 @@
 
     it { expect(for_node.body.sym_type?).to be(true) }
   end
+
+  describe '#post_condition_loop?' do
+    let(:source) { 'for foo in bar; baz; end' }
+
+    it { expect(for_node.post_condition_loop?).to be_falsey }
+  end
+
+  describe '#loop?' do
+    let(:source) { 'for foo in bar; baz; end' }
+
+    it { expect(for_node.loop?).to be_truthy }
+  end
 end
diff --git a/spec/rubocop/ast/until_node_spec.rb b/spec/rubocop/ast/until_node_spec.rb
index e2d4679ad..a02881faf 100644
--- a/spec/rubocop/ast/until_node_spec.rb
+++ b/spec/rubocop/ast/until_node_spec.rb
@@ -42,4 +42,32 @@
       it { expect(until_node.do?).to be_falsey }
     end
   end
+
+  describe '#post_condition_loop?' do
+    context 'with a statement until' do
+      let(:source) { 'until foo; bar; end' }
+
+      it { expect(until_node.post_condition_loop?).to be_falsey }
+    end
+
+    context 'with a modifier until' do
+      let(:source) { 'begin foo; end until bar' }
+
+      it { expect(until_node.post_condition_loop?).to be_truthy }
+    end
+  end
+
+  describe '#loop?' do
+    context 'with a statement until' do
+      let(:source) { 'until foo; bar; end' }
+
+      it { expect(until_node.loop?).to be_truthy }
+    end
+
+    context 'with a modifier until' do
+      let(:source) { 'begin foo; end until bar' }
+
+      it { expect(until_node.loop?).to be_truthy }
+    end
+  end
 end
diff --git a/spec/rubocop/ast/while_node_spec.rb b/spec/rubocop/ast/while_node_spec.rb
index 4933203b8..06449d166 100644
--- a/spec/rubocop/ast/while_node_spec.rb
+++ b/spec/rubocop/ast/while_node_spec.rb
@@ -42,4 +42,32 @@
       it { expect(while_node.do?).to be_falsey }
     end
   end
+
+  describe '#post_condition_loop?' do
+    context 'with a statement while' do
+      let(:source) { 'while foo; bar; end' }
+
+      it { expect(while_node.post_condition_loop?).to be_falsey }
+    end
+
+    context 'with a modifier while' do
+      let(:source) { 'begin foo; end while bar' }
+
+      it { expect(while_node.post_condition_loop?).to be_truthy }
+    end
+  end
+
+  describe '#loop?' do
+    context 'with a statement while' do
+      let(:source) { 'while foo; bar; end' }
+
+      it { expect(while_node.loop?).to be_truthy }
+    end
+
+    context 'with a modifier while' do
+      let(:source) { 'begin foo; end while bar' }
+
+      it { expect(while_node.loop?).to be_truthy }
+    end
+  end
 end