Rewrite ExpectationPartial and remove sub-types

The partial now contains the actual and source.
It also calls the correct match method on the matcher and constructs an 
expectation (which needs to be updated).

src/spectator/expectations/block_expectation_partial.cr

@@ -1,25 +0,0 @@
-require "./expectation_partial"
-
-module Spectator::Expectations
-  # Expectation partial variation that operates on a block.
-  struct BlockExpectationPartial(ReturnType) < ExpectationPartial
-    # Actual value produced by calling the block.
-    def actual
-      @block.call
-    end
-
-    # Creates the expectation partial.
-    # The label should be a string representation of the block.
-    # The block is stored for later use.
-    def initialize(@block : Proc(ReturnType), label, source_file, source_line)
-      super(label, source_file, source_line)
-    end
-
-    # Creates the expectation partial.
-    # The label is generated by calling to_s on the block.
-    # The block is stored for later use.
-    def initialize(@block : Proc(ReturnType), source_file, source_line)
-      super("<Proc>", source_file, source_line)
-    end
-  end
-end

src/spectator/expectations/expectation_partial.cr

@@ -1,39 +1,34 @@
+require "../matchers/match_data"
+require "../source"
+require "./actual"
+
 module Spectator::Expectations
-  # Base class for all expectation partials.
-  # An "expectation partial" stores part of an expectation (obviously).
-  # The part of the expectation this class covers is the actual value.
+  # Stores part of an expectation (obviously).
+  # The part of the expectation this type covers is the actual value and source.
   # This can also cover a block's behavior.
-  # Sub-types of this class are returned by the `DSL::ExampleDSL.expect` call.
-  abstract struct ExpectationPartial
-    # User-friendly string displayed for the actual expression being tested.
-    # For instance, in the expectation:
-    # ```
-    # expect(foo).to eq(bar)
-    # ```
-    # This property will be "foo".
-    # It will be the literal string "foo",
-    # and not the actual value of the foo.
-    getter label : String
+  struct ExpectationPartial
+    # The actual value being tested.
+    # This also contains its label.
+    getter actual : Actual
 
-    # Source file the expectation originated from.
-    getter source_file : String
+    # Location where this expectation was defined.
+    getter source : Source
 
-    # Line number in the source file the expectation originated from.
-    getter source_line : Int32
-
-    # Creates the base of the partial.
-    private def initialize(@label, @source_file, @source_line)
+    # Creates the partial.
+    def initialize(@actual, @source)
     end
 
     # Asserts that some criteria defined by the matcher is satisfied.
     def to(matcher) : Nil
-      report(eval(matcher))
+      match_data = matcher.match(@actual)
+      report(match_data)
     end
 
     # Asserts that some criteria defined by the matcher is not satisfied.
     # This is effectively the opposite of `#to`.
     def to_not(matcher) : Nil
-      report(eval(matcher, true))
+      match_data = matcher.negated_match(@actual)
+      report(match_data)
     end
 
     # ditto
@@ -42,14 +37,9 @@ module Spectator::Expectations
       to_not(matcher)
     end
 
-    # Evaluates the expectation and returns it.
-    private def eval(matcher, negated = false)
-      match_data = matcher.match(self)
-      Expectation.new(match_data, negated)
-    end
-
     # Reports an expectation to the current harness.
-    private def report(expectation : Expectation)
+    private def report(match_data : Matchers::MatchData)
+      expectation = Expectation.new(match_data, @source)
       Internals::Harness.current.report_expectation(expectation)
     end
   end

src/spectator/expectations/value_expectation_partial.cr

@@ -1,24 +0,0 @@
-require "./expectation_partial"
-
-module Spectator::Expectations
-  # Expectation partial variation that operates on a value.
-  struct ValueExpectationPartial(ActualType) < ExpectationPartial
-    # Actual value produced by the test.
-    # This is the value passed to the `Spectator::DSL::ExampleDSL#expect` macro.
-    getter actual
-
-    # Creates the expectation partial.
-    # The label should be a string representation of the actual value.
-    # The actual value is stored for later use.
-    def initialize(@actual : ActualType, label, source_file, source_line)
-      super(label, source_file, source_line)
-    end
-
-    # Creates the expectation partial.
-    # The label is generated by calling `to_s` on the actual value.
-    # The actual value is stored for later use.
-    def initialize(@actual : ActualType, source_file, source_line)
-      super(@actual.to_s, source_file, source_line)
-    end
-  end
-end

src/spectator/matchers/matcher.cr

@@ -5,13 +5,47 @@ module Spectator::Matchers
   # A matcher looks at something produced by the SUT
   # and evaluates whether it is correct or not.
   abstract struct Matcher
-    # Textual representation of what the matcher expects.
-    # This shouldn't be used in the conditional logic,
-    # but for verbose output to help the end-user.
-    abstract def label : String
+    # Short text about the matcher's purpose.
+    # This explains what condition satisfies the matcher.
+    # The description is used when the one-liner syntax is used.
+    # ```
+    # it { is_expected.to do_something }
+    # ```
+    # The phrasing should be such that it reads "it ___."
+    abstract def description : String
 
-    # Determines whether the matcher is satisfied with the value given to it.
-    # True is returned if the match was successful, false otherwise.
-    abstract def match(partial) : MatchData
+    # Message displayed when the matcher isn't satisifed.
+    # This is only called when `#matches?` returns false.
+    abstract def failure_message : String
+
+    # Message displayed when the matcher isn't satisifed and is negated.
+    # This is only called when `#does_not_match?` returns false.
+    #
+    # A default implementation of this method is provided,
+    # which causes compilation to fail.
+    # If the matcher supports negation, it must override this method.
+    def failure_message_when_negated : String
+      {% raise "Negation with #{@type.name} is not supported."}
+    end
+
+    # Checks whether the matcher is satisifed.
+    private abstract def match?(actual) : Bool
+
+    # If the expectation is negated, then this method is called instead of `#match?`.
+    # The default implementation of this method is to invert the result of `#match?`.
+    # If the matcher requires custom handling of negated matches,
+    # then this method should be overriden.
+    # Remember to override `#failure_message_when_negated` as well.
+    private def does_not_match?(actual) : Bool
+      !matches?(actual)
+    end
+
+    def match(actual)
+      matched = match?(actual)
+    end
+
+    def negated_match(actual)
+      matched = does_not_match?(actual)
+    end
   end
 end