added more documentation to get to 100% YARD coverage; fix YARD warnings

lib/rscons/builder.rb

@@ -7,14 +7,17 @@ module Rscons
   # Class to hold an object that knows how to build a certain type of file.
   class Builder
     # Return the name of the builder.
+    #
     # If not overridden this defaults to the last component of the class name.
     def name
       self.class.name.split(":").last
     end
 
-    # Return a set of default variable values for the Environment to use
-    # unless the user overrides any.
+    # Return a set of default construction variables for the builder.
+    #
     # @param env [Environment] The Environment.
+    #
+    # @return [Hash] Default construction variables.
     def default_variables(env)
       {}
     end
@@ -39,16 +42,33 @@ module Rscons
 
     # Return whether this builder object is capable of producing a given target
     # file name from a given source file name.
+    #
     # @param target [String] The target file name.
     # @param source [String, Array] The source file name(s).
     # @param env [Environment] The Environment.
+    #
+    # @return [Boolean]
+    #   Whether this builder object is capable of producing a given target
+    #   file name from a given source file name.
     def produces?(target, source, env)
       false
     end
 
     # Check if the cache is up to date for the target and if not execute the
     # build command.
-    # Return the name of the target or false on failure.
+    #
+    # @param short_cmd_string [String]
+    #   Short description of build action to be printed when env.echo ==
+    #   :short.
+    # @param target [String] Name of the target file.
+    # @param command [Array<String>]
+    #   The command to execute to build the target.
+    # @param sources [Array<String>] Source file name(s).
+    # @param env [Environment] The Environment executing the builder.
+    # @param cache [Cache] The Cache object.
+    #
+    # @return [String,false]
+    #   The name of the target on success or false on failure.
     def standard_build(short_cmd_string, target, command, sources, env, cache)
       unless cache.up_to_date?(target, command, sources, env)
         cache.mkdir_p(File.dirname(target))