Re: The onion truck strikes again ... Announcing rake

A couple of comments.

1.  I hate having to type Makefile instead of makefile.  make will accept 
either, so any make replacement should allow the initial lower case letter.  
Why anyone uses Makefile instead of makefile I've never understood...

2.  Automatic dependency checking (not just timestamps, but automatically 
discovering dependencies like "make depend") is important.

3.  How about implementing something like the clearcase concept of derived 
objects?

On Friday 14 March 2003 08:56 pm, Jim Weirich wrote:
> Ok, let me state from the beginning that I never intended to write this
> code.  I'm not convinced it is useful, and I'm not convinced anyone
> would even be interested in it.  All I can say is that Why's onion truck
> must by been passing through the Ohio valley.
>
> What am I talking about? ... A Ruby version of Make.
>
> See, I can sense you cringing already, and I agree.  The world certainly
> doesn't need yet another reworking of the "make" program.  I mean, we
> already have "ant".  Isn't that enough?
>
> It started yesterday.  I was helping a coworker fix a problem in one of
> the Makefiles we use in our project.  Not a particularly tough problem,
> but during the course of the conversation I began lamenting some of the
> shortcomings of make.  In particular, in one of my makefiles I wanted to
> determine the name of a file dynamically and had to resort to some
> simple scripting (in Ruby) to make it work.  "Wouldn't it be nice if you
> could just use Ruby inside a Makefile" I said.
>
> My coworker (a recent convert to Ruby) agreed, but wondered what it
> would look like.  So I sketched the following on the whiteboard...
>
>     "What if you could specify the make tasks in Ruby, like this ..."
>
>       task "build" do
>         java_compile(...args, etc ...)
>       end
>
>     "The task function would register "build" as a target to be made,
>     and the block would be the action executed whenever the build
>     system determined that it was time to do the build target."
>
> We agreed that would be cool, but writing make from scratch would be WAY
> too much work.  And that was the end of that!
>
> ... Except I couldn't get the thought out of my head.  What exactly
> would be needed to make the about syntax work as a make file?  Hmmm, you
> would need to register the tasks, you need some way of specifying
> dependencies between tasks, and some way of kicking off the process.
> Hey!  What if we did ... and fifteen minutes later I had a working
> prototype of Ruby make, complete with dependencies and actions.
>
> I showed the code to my coworker and we had a good laugh.  It was just
> about a page worth of code that reproduced an amazing amount of the
> functionality of make.  We were both truely stunned with the power of
> Ruby.
>
> But it didn't do everything make did.  In particular, it didn't have
> timestamp based file dependencies (where a file is rebuilt if any of its
> prerequisite files have a later timestamp).  Obviously THAT would be a
> pain to add and so Ruby Make would remain an interesting experiment.
>
> ... Except as I walked back to my desk, I started thinking about what
> file based dependecies would really need.  Rats!  I was hooked again,
> and by adding a new class and two new methods, file/timestamp
> dependencies were implemented.
>
> Ok, now I was really hooked.  Last night (during CSI!) I massaged the
> code and cleaned it up a bit.  The result is a bare-bones replacement
> for make in exactly 100 lines of code.
>
> For the curious, you can see it at ...
>   o http://w3.one.net/~jweirich/tools/rake/rake.rb (the code)
>   o http://w3.one.net/~jweirich/tools/rake/Rakefile (example Rakefile)
>   o ftp://ftp.one.net/pub/users/jweirich/tools/rake/rake-0.1.0.tgz
>       (the complete package).
>
>   (NOTE: The FTP server is flakey.  If it says it is busy, keep trying.
>          I'm looking into a different web/ftp hosting, but in the mean
>          time, good luck.)
>
> Oh, about the name.  When I wrote the example Ruby Make task on my
> whiteboard, my coworker exclaimed "Oh! I have the perfect name: Rake ...
> Get it?  Ruby-Make. Rake!"  He said he envisioned the tasks as leaves
> and Rake would clean them up  ... or something like that.  Anyways, the
> name stuck.
>
> Some quick examples ...
>
> A simple task to delete backup files ...
>
>    task :clean do
>      Dir['*~'].each {|fn| File.delete(fn) rescue nil }
>    end
>
> Note that task names are symbols (they are slightly easier to type than
> quoted strings ... but you may use quoted string if you would rather).
> Note also the use of "rescue nil" to trap and ignore errors in the
> File.delete command.
>
> To run it, just type "rake clean".  Rake will automatically find a
> Rakefile in the current directory (or above!) and will invoke the
> targets named on the command line.  If there are no targets explicitly
> named, rake will invoke the task "default".
>
> Here's another task with dependencies ...
>
>    task :clobber => [:clean] do
>      sys %{rm -r tempdir}
>    end
>
> Task :clobber depends upon task :clean, so :clean will be run before
>
> :clobber is executed.  "sys" is short for the "system" command (with an
>
> echo to standard out).
>
> Files are specified by using the "file" command.  It is similar to the
> task command, except that the task name represents a file, and the task
> will be run only if the file doesn't exist, or if its modification time
> is earlier than any of its prerequisites.
>
> Here is a file based dependency that will compile "hello.cc" to
> "hello.o".
>
>    file "hello.cc"
>    file "hello.o" => ["hello.cc"] do |t|
>      srcfile = t.name.sub(/\.o$/, ".cc")
>      sys %{g++ #{srcfile} -c -o #{t.name}}
>    end
>
> I normally specify file tasks with string (rather than symbols).  Some
> file names can't be represented by symbols.  Plus it makes the
> distinction between them more clear to the casual reader.  And yes,
> currently the "hello.cc" task with no prerequisites and no actions is
> required.
>
> Currently writing a task for each and every file in the project would be
> tedious at best.  I envision a set of libraries to make this job
> easier.  For instance, perhaps something like this ...
>
>    require 'rake/ctools'
>    Dir['*.c'].each do |fn|
>      c_source_file(fn)
>    end
>
> where "c_source_file" will create all the tasks need to compile all the
> C source files in a directory.  Any number of useful libraries could be
> created for rake.
>
> That's it.  There's no documentation (other than whats in this
> message).  Does this sound interesting to anyone?  If so, I'll continue
> to clean it up and write it up and publish it on RAA.  Otherwise, I'll
> leave it as an interesting excerise and a tribute to the power of Ruby.
>
> Why /might/ rake be intersting to Ruby programmers.  I don't know,
> perhaps ...
>
>    o No weird make syntax (only weird Ruby syntax :-)
>    o No need to edit or read XML (a la ant)
>    o Platform independent build scripts.
>    o Will run anywhere Ruby exists, so no need to have "make" installed.
>      If you stay away from the "sys" command and use things like
>      'ftools', you can have a perfectly platform independent
>       build script.  Also rake is only 100 lines of code, so it can
>       easily be packaged along with the rest of your code.
>
> So ... Sorry for the long rambling message.  Like I said, I never
> intended to write this code at all.

-- 
Seth Kurtzberg
M. I. S. Corp.
480-661-1849
[e-mail]