How to do multiline search and replace with a script?

Question

I'm trying to replace every multiline import inside a Python source file.. So, the source goes like

from XXX import (
   AAA,
   BBB,
)
from YYY import (
   CCC,
   DDD,
   EEE,
   ...
)
...other instructions...

and I'd like to get something like

from XXX import AAA, BBB
from YYY import CCC, DDD, EEE, ...
...other instructions...

I tried to use sed but it looks like it doesn't support non-greedy matching of the closing parenthesis, so it "eats" the second import.. :(
Any hint? Is this impossible with sed? Should I try with another tool?

Answer 1

Ummm... what's wrong with Python?

lineIter= iter(aFile)
for aLine in lineIter:
    if aLine.startswith("import"):
        if aLine.endswith("("):
            for aModule in lineIter:
                if aModule.endwith(")"):
                    break
                print "import", aModule.strip()
        else:
            print aLine.stri()
    else:
        print aLine.strip()

Answer 2

This might work for you:

sed '/^from/,/^)/{H;//{x;/)/{s/[\n()]//g;s/  */ /g;s/,$//;p;x}};d}' source
from XXX import AAA, BBB
from YYY import CCC, DDD, EEE, ...
...other instructions...

Answer 3

For posterity, here is a somewhat polished version of S.Lott's script (I'd have posted it as a comment, but it's too long ^^; ).. This version preserves indentation and produces a result closer to my example.

lineIter=iter(aFile)
for aLine in lineIter:
    s = aLine.strip()
    if s.startswith("from ") and s.endswith("("):
        complete = s[:-1]
        for aModule in lineIter:
            m = aModule.strip()
            if m.endswith(")"):
                break
            complete += m.strip()
        print complete
    else:
        print aLine,