Question

Can python generate path with multi-sub-paths by short form syntax like this ?

vars=project/{DEBIAN,usr/{bin,usr/{applications,icons,share}},computer}

Answer 1

Normally I would have suggested to use something like

def extend(base, *others):
    [base + o for o in others] if others else [base]

and then do

 extend("project", "/debian", *extend("/usr", *(extend("/bin") + extend("/usr", "/applications", "/icons", "/share"))))

. But as you prefer parsing a string, I try to provide an alternative:

def commasplit(s):
    start = 0
    level = 0
    for i, c in enumerate(s):
        if c == '{':
            level += 1
        elif c == '}':
            level -= 1
        elif c == ',' and level == 0:
            yield s[start:i]
            start = i+1
    yield s[start:]

def split(s):
    import re
    found = False
    for m in re.finditer("(\{.*\})",s):
        found = True
        for p in commasplit(s[m.start() + 1:m.end() - 1]):
            for i in split(p):
                yield s[:m.start()] + i + s[m.end():]
    if not found:
        yield s

cs = "a,b,c,{d,e,f},g"
print list(commasplit(cs)) # -> seems to work

s = "project/{DEBIAN,usr/{bin,usr/{applications,icons,share}},computer}"
print s
for n, i in enumerate(split(s)): print n, i # ->  as well.