Add docs to DSL and builder

src/spectator/dsl.cr

@@ -1,6 +1,8 @@
 require "./dsl/*"
 
 module Spectator
+  # Namespace containing methods representing the spec domain specific language.
+  # Also contains builders to generate classes and instances to later run the spec.
   module DSL
   end
 end

src/spectator/dsl/builder.cr

@@ -1,59 +1,98 @@
 module Spectator::DSL
+  # Global builder used to create the runtime instance of the spec.
+  # The DSL methods call into this module to generate parts of the spec.
+  # Once the DSL is done, the `#build` method can be invoked
+  # to create the entire spec as a runtime instance.
   module Builder
     extend self
 
-    @@group_stack = Array(ExampleGroupBuilder).new(1, root_group)
-
+    # Root group that contains all examples and groups in the spec.
     private class_getter root_group = RootExampleGroupBuilder.new
 
+    # Stack for tracking the current group the spec is working in.
+    # The last item (top of the stack) is the current group.
+    # The first item (bottom of the stack) is the root group (`#root_group`).
+    # The root group should never be popped.
+    @@group_stack = Array(ExampleGroupBuilder).new(1, root_group)
+
+    # Retrieves the current group the spec is working in.
     private def current_group
       @@group_stack.last
     end
 
+    # Adds a new group to the stack.
+    # Calling this method indicates the spec has entered a nested group.
     private def push_group(group : NestedExampleGroupBuilder)
       current_group.add_child(group)
       @@group_stack.push(group)
     end
 
+    # Begins a new nested group in the spec.
+    # A corresponding `#end_group` call must be made
+    # when the group being started is finished.
+    # See `NestedExampleGroupBuilder#initialize` for the arguments
+    # as arguments to this method are passed directly to it.
     def start_group(*args) : Nil
       group = NestedExampleGroupBuilder.new(*args)
       push_group(group)
     end
 
+    # Begins a new given group in the spec -
+    # that is, a group defined by the `given` keyword in the DSL.
+    # A corresponding `#end_group` call must be made
+    # when the group being started is finished.
+    # See `GivenExampleGroupBuilder#initialize` for the arguments
+    # as arguments to this method are passed directly to it.
     def start_given_group(*args) : Nil
       group = GivenExampleGroupBuilder.new(*args)
       push_group(group)
     end
 
+    # Marks the end of a group in the spec.
+    # This must be called for every `#start_group` and `#start_given_group` call.
+    # It is also important to line up the start and end calls.
+    # Otherwise examples might get placed into wrong groups.
     def end_group : Nil
       @@group_stack.pop
     end
 
+    # Adds an example type to the current group.
+    # The class name of the example should be passed as an argument.
+    # The example will be instantiated later.
     def add_example(example_type : Example.class) : Nil
       factory = ExampleFactory.new(example_type)
       current_group.add_child(factory)
     end
 
+    # Adds a block of code to run before all examples in the current group.
     def add_before_all_hook(&block : ->) : Nil
       current_group.add_before_all_hook(block)
     end
 
+    # Adds a block of code to run before each example in the current group.
     def add_before_each_hook(&block : ->) : Nil
       current_group.add_before_each_hook(block)
     end
 
+    # Adds a block of code to run after all examples in the current group.
     def add_after_all_hook(&block : ->) : Nil
       current_group.add_after_all_hook(block)
     end
 
+    # Adds a block of code to run after each example in the current group.
     def add_after_each_hook(&block : ->) : Nil
       current_group.add_after_each_hook(block)
     end
 
+    # Adds a block of code to run before and after each example in the current group.
+    # The block of code will be given another proc as an argument.
+    # It is expected that the block will call the proc.
     def add_around_each_hook(&block : Proc(Nil) ->) : Nil
       current_group.add_around_each_hook(block)
     end
 
+    # Builds the entire spec and returns it as a group.
+    # This should be called only once after the entire spec has been defined.
     protected def build : ExampleGroup
       root_group.build(Internals::SampleValues.empty)
     end