It is much easier to not try to parse options into complicated
structures until we actually collected all options: machine files,
command line, project()'s default_options, environment.
This creates a full set of option in environment that mirror those in
coredata, this mirroring of the coredata structure is convenient because
lookups int env (such as when initializing compilers) becomes a straight
dict lookup, with no list iteration. It also means that all of the
command line and machine files are read and stored in the correct order
before they're ever accessed, simplifying the logic of using them.
In most cases instead pass `for_machine`, the name of the relevant
machines (what compilers target, what targets run on, etc). This allows
us to use the cross code path in the native case, deduplicating the
code.
As one can see, environment got bigger as more information is kept
structured there, while ninjabackend got a smaller. Overall a few amount
of lines were added, but the hope is what's added is a lot simpler than
what's removed.
This isn't safe given the way python implements default arguments.
Basically python store a reference to the instance it was passed, and
then if that argument is not provided it uses the default. That means
that two calls to the same function get the same instance, if one of
them mutates that instance every subsequent call that gets the default
will receive the mutated instance. The idiom to this in python is to use
None and replace the None,
def in(value: str, container: Optional[List[str]]) -> boolean:
return src in (container or [])
if there is no chance of mutation it's less code to use or and take
advantage of None being falsy. If you may want to mutate the value
passed in you need a ternary (this example is stupid):
def add(value: str, container: Optional[List[str]]) -> None:
container = container if container is not None else []
container.append(value)
I've used or everywhere I'm sure that the value will not be mutated by
the function and erred toward caution by using ternaries for the rest.
This allows the person running configure (either a developer, user, or
distro maintainer) to keep a configuration of where various kinds of
files should end up.
Xavier Claessens