I hate XML, a long time ago, I also hated XML, but I also had some free time, and I played with building a build system in Boo. To match NAnt, I called it NUncle.

It never really gotten anywhere, but Georges Benatti has taken the code and created the Boo Build System. I am just taking a look, and it is fairly impressive. It has the concept of tasks and dependencies between them, as well as action that it can perform.

Here is a part of Boobs' own build script:

Task "build boobs", ["build engine", "build extensions"]:
	bc = Booc(
		SourcesSet   : FileSet("tools/boobs/**/*.boo"),
		OutputFile   : "build/boobs.exe"
		)
	bc.ReferencesSet.Include("build/boobs.engine.dll")
	bc.ReferencesSet.Include("build/boo.lang.useful.dll")
	bc.Execute()

Task "build engine":
	Booc(
		SourcesSet  : FileSet("src/boobs.engine/**/*.boo"),
		OutputFile  : "build/boobs.engine.dll",
		OutputTarget: TargetType.Library 
		).Execute()

Task "build extensions", ["build io.extensions", "build compiler.extensions"]

Task "build io.extensions":
	Booc(
		SourcesSet  : FileSet("src/extensions/boobs.io.extensions/**/*.boo"),
		OutputFile  : "build/boobs.io.extensions.dll",
		OutputTarget: TargetType.Library 
		).Execute()

Task "build compiler.extensions":
	bc = Booc(
		SourcesSet   : FileSet("src/extensions/boobs.compiler.extensions/**/*.boo"),
		OutputFile   : "build/boobs.compiler.extensions.dll",
		OutputTarget : TargetType.Library 
		)
	bc.ReferencesSet.Include("build/boobs.io.extensions.dll")
	bc.Execute()

I don't know about you, but this makes me feel very nice.

The concept is pretty obvious, I feel, and the really nice thing is that extending it is a piece of cake. Here is how you validate dates of two files:

def IsUpToDate(target as string, source as string):
	return true unless File.Exists(source)
	return false unless File.Exists(target)

	targetInfo = FileInfo(target)
	sourceInfo = FileInfo(source)
		
	return targetInfo.LastAccessTimeUtc >= sourceInfo.LastAccessTimeUtc

And its usage:

Cp("source.big", "dest.big") if not IsUpToDate("source.big", "dest.big")

Or, you know what, this is fairly routine, and it comes as part of the standard library for Boobs. Let us create something new, ConditionalCopy:

def ConditionalCp(src as string, dest as string):
	Cp(src, dest) if not IsUpToDate(src, dest)

Usage should be clear by now, I hope.