Question

How would you parse the ['i386', 'x86_64'] out of a string like '-foo 23 -bar -arch ppc -arch i386 -isysroot / -fno-strict-aliasing -fPIC'?

>>> my_arch_parse_function('-foo 23 -bar -arch i386 -arch x86_64 -isysroot /  -fno-strict-aliasing -fPIC')
>>> ['i386', 'x86_64']

Can this be done using regex, or only using modules like PyParsing, or manually splitting and iterating over the splits?

Assumption: -arch VAL are grouped together.

Answer 1

Regex: (?<=-arch )[^ ]+

>>> re.findall( r"(?<=-arch )([^ ]+)", r"'-foo 23 -bar -arch ppc -arch i386 -isysroot -fno-strict-aliasing -fPIC'" )
['ppc', 'i386']

Arbitrary whitespace

>>> foo = re.compile( r"(?<=-arch)\s+[^\s]+" )
>>> [ str.strip() for str in re.findall( foo, r"'-foo 23 -bar -arch ppc -arch i386 -isysroot -fno-strict-aliasing -fPIC'" ) ]
['ppc', 'i386']

P.S. There’s no x86_64 in that string, and are you trying to differentiate between -arch ppc and -arch i386?