Add/modify text between parentheses - shell

Question

I'm trying to make a classified text, and I'm having problem turning
(class1 (subclass1) (subclass2 item1 item2))
To
(class1 (subclass1 item1) (subclass2 item1 item2))
I have no idea to turn text above to below one, without caching subclass1 in memory. I'm using Perl on Linux, so any solution using shell script or Perl is welcome.
Edit: I've tried using grep, saving whole subclass1 in a variable, then modify and exporting it to the list; but the list may get larger and that way will use a lot of memory.

Answer 1

I have no idea to turn text above to below one
The general approach:
Parse the text.
You appear to have lists of space-separated lists and atoms. If so, the result could look like the following:
{
type => 'list',
value => [
{
type => 'atom',
value => 'class1',
},
{
type => 'list',
value => [
{
type => 'atom',
value => 'subclass1',
},
]
},
{
type => 'list',
value => [
{
type => 'atom',
value => 'subclass2',
},
{
type => 'atom',
value => 'item1',
},
{
type => 'atom',
value => 'item2',
},
],
}
],
}
It's possible that something far simpler could be generated, but you were light on details about the format.
Extract the necessary information from the tree.
You were light on details about the data format, but it could be as simple as the following if the above data structure was created by the parser:
my $item = $tree->{value}[2]{value}[1]{value};
Perform the required modifications.
You were light on details about the data format, but it could be as simple as the following if the above data structure was created by the parser:
my $new_atom = { type => 'atom', value => $item };
push #{ $tree->{value}[1]{value} }, $new_atom;
Serialize the data structure.
For the above data structure, you could use the following:
sub serialize {
my ($node) = #_;
return $node->{type} eq 'list'
? "(".join(" ", map { serialize($_) } #{ $node->{value} }).")"
: $node->{value};
}
Other approaches could be available depending on the specifics.