Add AST::NodeVisitor::Category simplifying code a bit

src/ameba/ast/visitors/node_visitor.cr

@@ -8,13 +8,17 @@ module Ameba::AST
   # visitor = Ameba::AST::NodeVisitor.new(rule, source)
   # ```
   class NodeVisitor < BaseVisitor
+    @[Flags]
+    enum Category
+      Macro
+    end
+
     # List of nodes to be visited by Ameba's rules.
     NODES = {
       Alias,
-      IsA,
       Assign,
-      Call,
       Block,
+      Call,
       Case,
       ClassDef,
       ClassVar,
@@ -25,20 +29,37 @@ module Ameba::AST
       HashLiteral,
       If,
       InstanceVar,
+      IsA,
       LibDef,
       ModuleDef,
       NilLiteral,
       StringInterpolation,
       Unless,
+      Until,
       Var,
       When,
       While,
-      Until,
     }
 
     @skip : Array(Crystal::ASTNode.class)?
 
-    def initialize(@rule, @source, skip = nil)
+    def self.category_to_node_classes(category : Category)
+      ([] of Crystal::ASTNode.class).tap do |classes|
+        classes.push(
+          Crystal::Macro,
+          Crystal::MacroExpression,
+          Crystal::MacroIf,
+          Crystal::MacroFor,
+        ) if category.macro?
+      end
+    end
+
+    def initialize(@rule, @source, *, skip : Category)
+      initialize @rule, @source,
+        skip: NodeVisitor.category_to_node_classes(skip)
+    end
+
+    def initialize(@rule, @source, *, skip : Array? = nil)
       @skip = skip.try &.map(&.as(Crystal::ASTNode.class))
       super @rule, @source
     end

src/ameba/rule/lint/not_nil.cr

@@ -36,12 +36,7 @@ module Ameba::Rule::Lint
     MSG          = "Avoid using `not_nil!`"
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)

src/ameba/rule/lint/not_nil_after_no_bang.cr

@@ -34,12 +34,7 @@ module Ameba::Rule::Lint
     MSG          = "Use `%s! {...}` instead of `%s {...}.not_nil!`"
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)

src/ameba/rule/performance/chained_call_with_no_bang.cr

@@ -59,12 +59,7 @@ module Ameba::Rule::Performance
     MSG = "Use bang method variant `%s!` after chained `%s` call"
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)

src/ameba/rule/performance/compact_after_map.cr

@@ -31,12 +31,7 @@ module Ameba::Rule::Performance
     MSG          = "Use `compact_map {...}` instead of `map {...}.compact`"
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)

src/ameba/rule/performance/first_last_after_filter.cr

@@ -36,12 +36,7 @@ module Ameba::Rule::Performance
     MSG_REVERSE = "Use `reverse_each.find {...}` instead of `%s {...}.%s`"
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)

src/ameba/rule/performance/flatten_after_map.cr

@@ -31,12 +31,7 @@ module Ameba::Rule::Performance
     MSG          = "Use `flat_map {...}` instead of `map {...}.flatten`"
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)

src/ameba/rule/performance/map_instead_of_block.cr

@@ -32,12 +32,7 @@ module Ameba::Rule::Performance
     MSG        = "Use `%s {...}` instead of `map {...}.%s`"
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)

src/ameba/rule/performance/size_after_filter.cr

@@ -42,12 +42,7 @@ module Ameba::Rule::Performance
     MSG       = "Use `count {...}` instead of `%s {...}.size`."
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)

src/ameba/rule/style/is_a_filter.cr

@@ -49,12 +49,7 @@ module Ameba::Rule::Style
     OLD = "%s {...}"
 
     def test(source)
-      AST::NodeVisitor.new self, source, skip: [
-        Crystal::Macro,
-        Crystal::MacroExpression,
-        Crystal::MacroIf,
-        Crystal::MacroFor,
-      ]
+      AST::NodeVisitor.new self, source, skip: :macro
     end
 
     def test(source, node : Crystal::Call)