The text file has hundreds of these entries (format is MT940 bank statement)

{1:F01AHHBCH110XXX0000000000}{2:I940X           N2}{3:{108:XBS/091502}}{4:
:20:XBS/091202/0001
:25:5887/507004-50
:28C:140/1
:60F:C0914CHF7789,
:61:0912021202D36,80NTRFNONREF//0887-1202-29-941
04392579-0 LUTHY + xxx, ZUR
:86:6034?60LUTHY + xxxx, ZUR vom 01.12.09 um 16:28 Karten-Nr. 2232
2579-0
:62F:C091202CHF52,2
:64:C091302CHF52,2
-}

This should go into an Array of Hashes like

[{"1"=>"F01AHHBCH110XXX0000000000"},
  "2"=>"I940X           N2", 
   3 => {108=>"XBS/091502"}
etc.
} ]

I tried it with tree top, but it seemed not to be the right way, because it's more for something you want to do calculations on, and I just want the information.

grammar Mt940

  rule document
    part1:string spaces [:|/] spaces part2:document 
    {
      def eval(env={})
        return part1.eval, part2.eval
      end
    }
    / string
    /  '{' spaces document spaces '}' spaces
    {
      def eval(env={})
        return [document.eval]
      end
    }
  end
end

I also tried with a regular expression

matches = str.scan(/\A[{]?([0-9]+)[:]?([^}]*)[}]?\Z/i)

but it's difficult with recursion ...

How can I solve this problem?