Move example filters from === to their own types

src/spectator/example.cr

@@ -59,21 +59,5 @@ module Spectator
     def to_json(json : ::JSON::Builder)
       json.string(to_s)
     end
-
-    # Checks if this example matches some criteria.
-    # This is used to filter examples.
-    def ===(other)
-      other === to_s
-    end
-
-    # Checks if this example is at the specified source.
-    def ===(other : Source)
-      source == other
-    end
-
-    # Checks if this example is at the specified line number.
-    def ===(other : Int32)
-      source.line === other
-    end
   end
 end

src/spectator/example_filter.cr

@@ -1,24 +1,9 @@
 module Spectator
-  # Checks examples to determine which should be run.
-  class ExampleFilter
-    # The criteria for filtering examples can be multiple types.
-    # A `String` will exact-match an example's name.
-    # A `Regex` will perform a regular expression match on the example's name.
-    # A `Source` will check if the example is in the specified file on a given line.
-    # An `Int32` will check if an example is on a given line.
-    alias Type = String | Regex | Source | Int32
-
-    # Creates the example filter.
-    # The *criteria* should be a list of what to filter on.
-    def initialize(@criteria = [] of Type)
-    end
-
+  # Base class for all example filters.
+  # Checks whether an example should be run.
+  # Sub-classes must implement the `#includes?` method.
+  abstract class ExampleFilter
     # Checks if an example is in the filter, and should be run.
-    def includes?(example)
-      return true if @criteria.empty?
-      @criteria.any? do |criterion|
-        example === criterion
-      end
-    end
+    abstract def includes?(example : Example) : Bool
   end
 end

src/spectator/includes.cr

@@ -28,7 +28,11 @@ require "./config"
 require "./config_builder"
 require "./config_source"
 require "./command_line_arguments_config_source"
+
 require "./example_filter"
+require "./source_example_filter"
+require "./line_example_filter"
+require "./name_example_filter"
 
 require "./example_failed"
 require "./expectation_failed"

src/spectator/line_example_filter.cr

@@ -0,0 +1,13 @@
+module Spectator
+  # Filter that matches examples on a given line.
+  class LineExampleFilter < ExampleFilter
+    # Creates the example filter.
+    def initialize(@line : Int32)
+    end
+
+    # Checks whether the example satisfies the filter.
+    def includes?(example)
+      @line == example.source.line
+    end
+  end
+end

src/spectator/name_example_filter.cr

@@ -0,0 +1,13 @@
+module Spectator
+  # Filter that matches examples based on their name.
+  class NameExampleFilter < ExampleFilter
+    # Creates the example filter.
+    def initialize(@name : String)
+    end
+
+    # Checks whether the example satisfies the filter.
+    def includes?(example)
+      @name == example.to_s
+    end
+  end
+end

src/spectator/source_example_filter.cr

@@ -0,0 +1,14 @@
+module Spectator
+  # Filter that matches examples in a given file and line.
+  class SourceExampleFilter < ExampleFilter
+    # Creates the filter.
+    # The *source* indicates which file and line the example must be on.
+    def initialize(@source : Source)
+    end
+
+    # Checks whether the example satisfies the filter.
+    def includes?(example)
+      @source === example.source
+    end
+  end
+end