path.rb in build-files-1.0.4

- old
+ new

@@ -34,11 +34,11 @@
 				else
 					path.split(File::SEPARATOR)
 				end
 			end
 			
-			# Return the shortest relative path to get to path from root:
+			# Return the shortest relative path to get to path from root. Root should be a directory with which you are computing the relative path.
 			def self.shortest_path(path, root)
 				path_components = Path.components(path)
 				root_components = Path.components(root)
 				
 				# Find the common prefix:
@@ -93,14 +93,18 @@
 			
 			def basename
 				self.parts.last
 			end
 			
+			def start_with?(*args)
+				@full_path.start_with?(*args)
+			end
+			
 			alias parts components
 			
 			def relative_path
-				@relative_path ||= Path.relative_path(@root.to_s, @full_path)
+				@relative_path ||= Path.relative_path(@root.to_s, @full_path).freeze
 			end
 			
 			def relative_parts
 				dirname, _, basename = self.relative_path.rpartition(File::SEPARATOR)
 				
@@ -131,9 +135,18 @@
 				self.class.new(File.join(root, relative_path), root, relative_path)
 			end
 			
 			def self.join(root, relative_path)
 				self.new(File.join(root, relative_path), root)
+			end
+			
+			# Expand a subpath within a given root, similar to `File.expand_path`
+			def self.expand(subpath, root = Dir.getwd)
+				if subpath.start_with? File::SEPARATOR
+					self.new(subpath)
+				else
+					self.join(root, subpath)
+				end
 			end
 			
 			def shortest_path(root)
 				self.class.shortest_path(self, root)
 			end