Update PredicateMatcher to use MatchData

src/spectator/matchers/predicate_matcher.cr

@@ -12,13 +12,10 @@ module Spectator::Matchers
     end
 
     # Determines whether the matcher is satisfied with the value given to it.
-    # True is returned if the match was successful, false otherwise.
-    def match?(partial)
-      actual = partial.actual
-
+    private def match?(values)
       # Test each predicate and immediately return false if one is false.
       {% for attribute in ExpectedType.keys %}
-      return false unless actual.{{attribute}}?
+      return false unless values[{{attribute.symbolize}}]
       {% end %}
 
       # All checks passed if this point is reached.
@@ -28,19 +25,44 @@ module Spectator::Matchers
     # Determines whether the matcher is satisfied with the partial given to it.
     # `MatchData` is returned that contains information about the match.
     def match(partial) : MatchData
-      raise NotImplementedError.new("#match")
+      values = snapshot_values(partial.actual)
+      MatchData.new(match?(values), values, partial.label)
     end
 
-    # Describes the condition that satisfies the matcher.
-    # This is informational and displayed to the end-user.
-    def message(partial)
-      "Expected #{partial.label} to be #{label}"
+    # Captures all of the actual values.
+    # A `NamedTuple` is returned,
+    # with each key being the attribute.
+    private def snapshot_values(actual)
+      {% begin %}
+      {
+        {% for attribute in ExpectedType.keys %}
+        {{attribute}}: actual.{{attribute}}?,
+        {% end %}
+      }
+      {% end %}
     end
 
-    # Describes the condition that won't satsify the matcher.
-    # This is informational and displayed to the end-user.
-    def negated_message(partial)
-      "Expected #{partial.label} to not be #{label}"
+    # Match data specific to this matcher.
+    private struct MatchData(ActualType) < MatchData
+      # Creates the match data.
+      def initialize(matched, @values : ActualType, @actual_label : String)
+        super(matched)
+      end
+
+      # Information about the match.
+      getter values
+
+      # Describes the condition that satisfies the matcher.
+      # This is informational and displayed to the end-user.
+      def message
+        "#{@actual_label} is " + {{ActualType.keys.splat.stringify}}
+      end
+
+      # Describes the condition that won't satsify the matcher.
+      # This is informational and displayed to the end-user.
+      def negated_message
+        "#{@actual_label} is not " + {{ActualType.keys.splat.stringify}}
+      end
     end
   end
 end