Rake: How do I Override Var's Used by a Rule?


#1

All:

For our rakefile system, we would like to have the ability to build
either a “debug” version of our code, or a “release” version. My plan is
to have 2 separate high-level tasks, where one of them invokes the other

  • except with overridden variables. I wish I knew how to do this. :wink:
    Please help.

Here are my tasks (edited for brevity):

=============================
task :debug_build => [:build_depend, :build_obj] do
# handle the linking
end

task :release_build do
# Invoke the debug_build task, but override the following var’s:
# C_OPTIMIZE_LVL="-o2"
# C_DEBUG=""
end

My .c -> .obj rule looks like this:

=============================
rule “.#{OBJ_EXT}” => lambda{|objfile| find_source(objfile)} do |t|
sh “#{COMPILER} #{C_OPTS} #{C_DEBUG} #{C_OPTIMIZE_LVL} #{C_OBJ_DIR}
#{C_INC_PATHS} #{C_FLAGS} #{C_TARGET} #{t.source}”
end

So the only difference between the debug_build and release_build tasks
is the compile line. NOTE: I currently read those variables (COMPILER,
C_OPTS, etc.) from another rakefile.

Any suggestions? Am I going about this the wrong way?

Thanks,
Brock


#2

As usual, right after I finally decide to post something to a forum, I
trip over an answer myself. I found that this seems to do the trick.

task :release_build do
C_OPTIMIZE_LVL="-o2"
C_DEBUG=""
Rake::Task[:debug_build].invoke
end

Is this a good way to do this? Is there a better one? Should I just stop
asking questions and move on?

Thanks,
B

Brock Rycenga wrote:

All:

For our rakefile system, we would like to have the ability to build
either a “debug” version of our code, or a “release” version. My plan is
to have 2 separate high-level tasks, where one of them invokes the other

  • except with overridden variables. I wish I knew how to do this. :wink:
    Please help.

Here are my tasks (edited for brevity):

=============================
task :debug_build => [:build_depend, :build_obj] do
# handle the linking
end

task :release_build do
# Invoke the debug_build task, but override the following var’s:
# C_OPTIMIZE_LVL="-o2"
# C_DEBUG=""
end

My .c -> .obj rule looks like this:

=============================
rule “.#{OBJ_EXT}” => lambda{|objfile| find_source(objfile)} do |t|
sh “#{COMPILER} #{C_OPTS} #{C_DEBUG} #{C_OPTIMIZE_LVL} #{C_OBJ_DIR}
#{C_INC_PATHS} #{C_FLAGS} #{C_TARGET} #{t.source}”
end

So the only difference between the debug_build and release_build tasks
is the compile line. NOTE: I currently read those variables (COMPILER,
C_OPTS, etc.) from another rakefile.

Any suggestions? Am I going about this the wrong way?

Thanks,
Brock


#3

This is really starting to feel like I am having a conversation with
myself…

Even if this is the correct way to do this, it would be really nice to
know how to override var’s from the command line. For example, with
make, I could do the following:

make -f mymakefile OPT1=“new_val” OPT2=“over_new_val” mytarget

This would override value for OPT1 and OPT2 in the makefile. Is there
something equivalent in rake?

Thanks,
B

Brock Rycenga wrote:

As usual, right after I finally decide to post something to a forum, I
trip over an answer myself. I found that this seems to do the trick.

task :release_build do
C_OPTIMIZE_LVL="-o2"
C_DEBUG=""
Rake::Task[:debug_build].invoke
end

Is this a good way to do this? Is there a better one? Should I just stop
asking questions and move on?

Thanks,
B


#4

On Wed, Oct 22, 2008 at 11:55 AM, Brock Rycenga
removed_email_address@domain.invalid wrote:

This would override value for OPT1 and OPT2 in the makefile. Is there
something equivalent in rake?

OPT1 = ENV[‘OPT1’] || ‘default value’

On another note, top posting is discouraged on this list.

HTH,
Michael G.


#5

Michael G. wrote:

On Wed, Oct 22, 2008 at 11:55 AM, Brock Rycenga
removed_email_address@domain.invalid wrote:

This would override value for OPT1 and OPT2 in the makefile. Is there
something equivalent in rake?

OPT1 = ENV[‘OPT1’] || ‘default value’

On another note, top posting is discouraged on this list.

HTH,
Michael G.

Thanks Michael. That does help, and that’s what I was looking for.

Brock


#6

On Thu, 23 Oct 2008, Brock Rycenga wrote:

Is this a good way to do this? Is there a better one? Should I just stop
asking questions and move on?

I’d make them global variables, just to make them stand out, show they
are shared between tasks, but I don’t use rake that much at the moment

As to the next question about command line options, then my reading of
rake --help suggests you can’t set them from the command line, but you
could set environment vars and read those inside the rakefile. Or read
a config file with values in it.

Thanks,
B

    Hugh