Re: [Scons-dev] How to get variables passed to Env(variables = whatever)?
On Sat, Oct 6, 2012 at 2:53 PM, Left Right wrote:
> > With Variables you can control logic for example on how to deal with
> unknown values
> > Jason
>
> OK... well, my question was how to control it? Right now it does the
> opposite of what I need. How to make it do what I need?
> I.e. I want to allow FLEX_HOME to be set in this way (this is a
> directory name, so the way variables have special function for
> directories looks appealing)
>
I think you have a basic (and common) confusion between the construction
environment (what Environment() makes) and the shell environment which is
passed to commands that are executed by SCons. That environment is stored
in one sub-key of the construction environment. So:
env = Environment()
env['FOO'] = 'Foo in construction environment'
env['ENV']['FOO'] = 'Foo passed to subshells'
env.Command('tgt', 'src', 'make-target $TARGET $SOURCE FOO=$FOO')
In a SConstruct like the above, the actual command executed will be:
make-target tgt src "Foo in construction environment"
However if make-target itself is a shell script, and that shell script
contains a $FOO, that one will expand to "Foo passed to subshells".
Basically, SCons is not like Make; construction variables are distinct from
the shell environment and each can be manipulated completely independently.
I think what you care about is setting FLEX_HOME in the shell environment
passed to commands executed by SCons, right? In that case you want to set
(in any way you like) env['ENV']['FLEX_HOME']. Note that simply applying a
Variables object to an Environment sets construction variables, not shell
environment variables. That's probably what was tripping you up.
--
Gary
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Re: [Scons-dev] How to get variables passed to Env(variables = whatever)?
> With Variables you can control logic for example on how to deal with unknown > values > Jason OK... well, my question was how to control it? Right now it does the opposite of what I need. How to make it do what I need? I.e. I want to allow FLEX_HOME to be set in this way (this is a directory name, so the way variables have special function for directories looks appealing) > If all you're looking to do is have foo in the shell environment of the > commands you run > -Bill No. This variable is most likely not set in the shell environment, when the build script is called. It is very likely that users will have to set it. > then you don't need to use Variables at all Fair enough... but I thought it's a suggested way of doing it. > If you want to pass foo on the scons command line and have Not sure. I want to pass it to my function, that will do something based on that variable (in this particular case, it will try to find a bunch of programs, configuration files etc.) Best. Oleg ___ Scons-dev mailing list Scons-dev@scons.org http://two.pairlist.net/mailman/listinfo/scons-dev
Re: [Scons-dev] How to get variables passed to Env(variables = whatever)?
Oleg,
If all you're looking to do is have foo in the shell environment of the
commands you run, then you don't need to use Variables at all.
If you want to pass foo on the scons command line and have that affect the
Environment(), though not the shell environment unless you explicitly copy the
value:
env=Environment()
env['ENV']['foo']=env['foo']
Then Variables is useful.
Sounds like you really need to do a thorough read of the users guide and the
man page.
-Bill
On Oct 5, 2012, at 9:42 AM, "Kenny, Jason L" wrote:
> Variable objects are a defined type that allow for some basic validation, and
> conversion. With Variables you can control logic for example on how to deal
> with unknown values. This was meant to be an improvement over just taking the
> arguments and passing them in to the Environment.
>
> Jason
>
> -Original Message-
> From: scons-dev-boun...@scons.org [mailto:scons-dev-boun...@scons.org] On
> Behalf Of Left Right
> Sent: Friday, October 05, 2012 11:14 AM
> To: scons-dev@scons.org
> Subject: Re: [Scons-dev] How to get variables passed to Env(variables =
> whatever)?
>
> Nope, it doesn't. It was a typo, in the original code it was Environment, not
> Env.
> I can, however, do it like so:
>
> env = Environment(ENV = { 'foo' : 42 })
> env['ENV']['foo'] <--- this works then
>
> But was curious of the reason why not allow to do it via Variables?
>
> Thanks.
>
> Oleg
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Re: [Scons-dev] How to get variables passed to Env(variables = whatever)?
Variable objects are a defined type that allow for some basic validation, and
conversion. With Variables you can control logic for example on how to deal
with unknown values. This was meant to be an improvement over just taking the
arguments and passing them in to the Environment.
Jason
-Original Message-
From: scons-dev-boun...@scons.org [mailto:scons-dev-boun...@scons.org] On
Behalf Of Left Right
Sent: Friday, October 05, 2012 11:14 AM
To: scons-dev@scons.org
Subject: Re: [Scons-dev] How to get variables passed to Env(variables =
whatever)?
Nope, it doesn't. It was a typo, in the original code it was Environment, not
Env.
I can, however, do it like so:
env = Environment(ENV = { 'foo' : 42 })
env['ENV']['foo'] <--- this works then
But was curious of the reason why not allow to do it via Variables?
Thanks.
Oleg
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Re: [Scons-dev] How to get variables passed to Env(variables = whatever)?
Nope, it doesn't. It was a typo, in the original code it was
Environment, not Env.
I can, however, do it like so:
env = Environment(ENV = { 'foo' : 42 })
env['ENV']['foo'] <--- this works then
But was curious of the reason why not allow to do it via Variables?
Thanks.
Oleg
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Re: [Scons-dev] How to get variables passed to Env(variables = whatever)?
Some more info: for k in keys: print 'will try to set: %s' % k try: save[k] = self._dict[k] except KeyError: print 'and fail...: %s' % k # No value may have been set if they tried to pass in a # reserved variable name like TARGETS. pass This is where it fails... why?.. I'm giving it a totally rouge name, it can't be a reserved name or anything. In particular, I need to allow specify $FLEX_HOME, if it's not set in current shell, or to override it. Unfortunately, none of *my* code runs before this point, so I cannot affect this *decision*. Thanks. ___ Scons-dev mailing list Scons-dev@scons.org http://two.pairlist.net/mailman/listinfo/scons-dev
Re: [Scons-dev] How to get variables passed to Env(variables = whatever)?
On Oct 5, 2012 9:36 AM, "Left Right" wrote:
>
> Hi,
> I've found this page:
http://www.scons.org/doc/1.1.0/HTML/scons-user/x2361.html
> And it shows that the user could, in theory do something like:
>
> v = Variables()
> v.Add('foo', 42)
> env = Env(variables = v)
This should work, except the name of the environment constructor is
Environment(), not Env().
Then env['foo'] should be 42.
> I was struggling to find where did this variable go, but no traces...
> I would expect them to appear in
>
> def generate(env):
> env.get('foo') <--- but it doesn't exist here
> env._dict.keys() <--- foo doesn't exist here either...
>
> Why? How else should I look for it?
>
> Thanks.
>
> Oleg
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[Scons-dev] How to get variables passed to Env(variables = whatever)?
Hi,
I've found this page: http://www.scons.org/doc/1.1.0/HTML/scons-user/x2361.html
And it shows that the user could, in theory do something like:
v = Variables()
v.Add('foo', 42)
env = Env(variables = v)
I was struggling to find where did this variable go, but no traces...
I would expect them to appear in
def generate(env):
env.get('foo') <--- but it doesn't exist here
env._dict.keys() <--- foo doesn't exist here either...
Why? How else should I look for it?
Thanks.
Oleg
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