Help needed with nested parsing of file into objects

[Alain Ketterlin]

richard <pullenjenna10 at gmail.com> writes:


[I'm leaving the data in the message in case anybody has troubles going
up-thread.]

> Hi guys still struggling to get the code that was posted to me on this
> forum to work in my favour and get the output in the format shown
> above. This is what I have so far. Any help will be greatly
> apprectiated.
>
> output trying to achieve
> parsed = [
>     {
>       "a":"a",
>       "b":"b",
>       "c":"c",
>       "A_elements":[
>           {
>             "a":1,
>             "b":2,
>             "c":3
>           },
>           {
>              "a":1,
>              "b":2,
>              "c":3
>           }
>        ],
>       "B_elements":[
>           {
>             "a":1,
>             "b":2,
>             "c":3,
>             "C_elements":[
>                  {
>                      "a":1,
>                      "b":2,
>                      "c":3
>                   },
>                   {
>                       "a":1,
>                       "b":2,
>                       "c":3
>                   }
>              ]
>           }
>        ]
>     },
>
>     {
>       "a":"1",
>       "b":"2",
>       "c":"3",
>     }
>
> ]
>
> file format unchangeable
>
> An instance of TestArray
>  a=a
>  b=b
>  c=c
>  List of 2 A elements:
>   Instance of A element
>    a=1
>    b=2
>    c=3
>   Instance of A element
>    d=1
>    e=2
>    f=3
>  List of 1 B elements
>   Instance of B element
>    a=1
>    b=2
>    c=3
>    List of 2 C elements
>     Instance of C element
>      a=1
>      b=2
>      c=3
>     Instance of C element
>      a=1
>      b=2
>      c=3
>
> An instance of TestArray
>  a=1
>  b=2
>  c=3
>
> def test_parser(filename):
>     class Stanza:
>         def __init__(self, values):
>             for attr, val in values:
>                 setattr(self, attr, val)
>
>     def build(couple):
>         if "=" in couple[0]:
>             attr, val = couple[0].split("=")
>             return attr,val
>         elif "Instance of" in couple[0]:
>             match = re.search("Instance of (.+) element", couple[0])
>             return ("attr_%s" % match.group(1),Stanza(couple[1]))
>         elif "List of" in couple[0]:
>             match = re.search("List of \d (.+) elements", couple[0])
>             return ("%s_elements" % match.group(1),couple[1])

You forgot one case:

    def build(couple):
        if "=" in couple[0]:
            attr, val = couple[0].split("=")
            return attr,val
        elif "Instance of" in couple[0]:
            #match = re.search("Instance of (.+) element", couple[0])
            #return ("attr_%s" % match.group(1),Stanza(couple[1]))
            return dict(couple[1])
        elif "An instance of" in couple[0]: # you forgot that case
            return dict(couple[1])
        elif "List of" in couple[0]:
            match = re.search("List of \d (.+) elements", couple[0])
            return ("%s_elements" % match.group(1),couple[1])
        else:
            pass # put a test here

>     fo = open(filename, "r")
>     RE = re.compile("( *)(.*)")
>     stack = [("-",[])]
>     for line in fo:
>         matches = RE.match(line)
>         if len(matches.group(2)) > 0:
>             depth = 1 + len(matches.group(1))
>             while len(stack) > depth:
>                 stack[-2][1].append(build(stack[-1]))
>                 del stack[-1]
>             stack.append( (matches.group(2),[]) )
>     while len(stack) > 1:
>         stack[-2][1].append(stack[-1])

Change this to:

          stack[-2][1].append(build(stack[-1])) # call build() here also

>         del stack[-1]
>     return stack

Actually the first and only element of stack is a container: all you
need is the second element of the only tuple in stack, so:

      return stack[0][1]

and this is your list. If you need it pretty printed, you'll have to
work the hierarchy.

-- Alain.