Implemented SimpleBuilder and updated Environment#add_builder method to support it

lib/rscons/builders/simple_builder.rb

@@ -0,0 +1,37 @@
+module Rscons
+  module Builders
+    # A Generic builder class whose name and operation is defined at
+    # instantiation.
+    class SimpleBuilder < Builder
+      # The name of this builder when registered in an environment
+      attr_reader :name
+
+      # Create a new builder with the given name and action.
+      #
+      # @param name  [String,Symbol] The name of the builder when registered.
+      # @param block [Block]
+      #   The action to perform when the builder is processed. The provided
+      #   block must return the target file on success or false on failure.
+      #   The provided block should have the same signature as {Builder#run}.
+      def initialize(name, &block)
+        @name  = name.to_s
+        @block = block
+      end
+
+      # Run the builder to produce a build target.
+      #
+      # @param target [String] Target file name.
+      # @param sources [Array<String>] Source file name(s).
+      # @param cache [Cache] The Cache object.
+      # @param env [Environment] The Environment executing the builder.
+      # @param vars [Hash,VarSet] Extra construction variables.
+      #
+      # @return [String,false]
+      #   Name of the target file on success or false on failure.
+      def run(target, sources, cache, env, vars)
+        @block.call(target, sources, cache, env, vars)
+      end
+    end
+  end
+end
+

lib/rscons/environment.rb

@@ -120,10 +120,26 @@ module Rscons
 
     # Add a {Builder} object to the Environment.
     #
-    # @param builder [Builder] The {Builder} object to add.
+    # @overload add_builder(builder)
+    #   Registers a builder with the environment
+    #   @param builder [Builder] An instance of the builder to register.
+    #
+    # @overload add_builder(builder,&action)
+    #   Register a new {Builders::SimpleBuilder} with the environment.
+    #
+    #   @param builder [String,Symbol]
+    #     The name of the builder to add.
+    #
+    #   @param action [Block]
+    #     A block that will be called when the builder is executed to generate
+    #     a target file. The provided block should have the same prototype as
+    #     {Rscons::Builder#run}
     #
     # @return [void]
-    def add_builder(builder)
+    def add_builder(builder, &action)
+      if not builder.is_a? Rscons::Builder
+        builder = Rscons::Builders::SimpleBuilder.new(builder, &action)
+      end
       @builders[builder.name] = builder
       var_defs = builder.default_variables(self)
       if var_defs