From: Hugh Sasse Staff Elec Eng <hgs@...>
Date: 2002-02-08T03:06:16+09:00
Subject: Re: mkmf, extconf.rb

On Fri, 8 Feb 2002 nobu.nokada@softhome.net wrote:

> Hi,
>
> At Thu, 7 Feb 2002 19:22:28 +0900,
> Hugh Sasse Staff Elec Eng <hgs@dmu.ac.uk> wrote:
> > > > Further to my suggestions in Ruby-Talk:31391, about adding methods to
> > > > mkmf so that rules can be added to makefiles, I have "lashed together"
	[...]
> > > I guess you can do it with `depend' file.
> >
> > I have found that bit of code in mkmf:
> (snip)
> > I don't think you can use this for adding more make rules, because it is
> > not completely transparent.  Suppose your action includes  ruby code
> > which does 'gsub(/\.o\b/, ".#{$OBJEXT}")'.  This will get rendered as
> > "gsub(/\.#{$OBJEXT}\b/" etc.
>
> It's sure not to be designed for general purpose.
>
> > Maybe this could be extracted to a method, and have the substitution
> > optional?
>
> def add_rules(rules)
>   open("Makefile", "a") do |f|
>     if defined? yield
>       rules.each {|l| f << yield l}
>     else
>       f << rules
>     end
>   end
> end

Yes, I like the idea of using a block

>
> # or as you wrote in [ruby-talk:33238], append to $makerules.
> $makerules = ""
> def add_rules(rules)
>   f = $makerules
>   if defined? yield
>     rules.each {|l| f << yield l}
>   else
>     f << rules
>   end
> end
>
Whichever you are happiest with.  "Global variables are maybe best
avoided."  seems to be a rule of thumb which may be relevant.
I couldn't think of a good way round that at the time.

> # And then
> add_rules("depend") {|l| l.gsub(/\.o\b/, ".#{$OBJEXT}")}
>
Yes,

> add_rules << EOM
> # rules
> EOM

but I don't think you'd need that, you just to the call from extconf.rb
(see below) rather than modifying the module mkmf itself.
>
>
> # or maybe,
> Makerules = []
> def Makerules.add(rules, &block)
>   self << [rules, block]
> end
> def Makerules.write(to)
>   each {|r, b| b ? r.each {|l| to << b.call(l)} : to << l}
> end
>

I would be happy with these.

As far as I can see from my reading of `man make` appending the rules
at the end of the makefile would be fine, so people could call this from
extconf.rb and have it work:
    require mkmf
    create_makefile('thingy')
    add_rules <<EORULES
    tarfile: this.c that.c thingy.h extconf.rb
    	 tar cvf thingy.tar this.c that.c thingy.h extconf.rb

    EORULES

I don't think I have access to enough versions of make to really test
this.  (I'm thinking of "Are normal 'target: dependency; action' rules
allowed after suffix rules?".)

>
> --
> Nobu Nakada
>
	Hugh