Conversion of PLC Logic from One platform to another

Hi All,
Is there any tool which can convert ladder logic from any platform to any platform e.g. Rockwell to mitsubishi logic.
if No then how can we develop the tool/converter to do the same.
please share your ideas/suggestions.

Thanks in advance.

you write a parser...I have written a parser/compiler( the back end ) that converts ladder to c and then used third-party software to convert c to machine code.
Unfortunately, I broke the code, I still have it somewhere. I used an LL1 parser ...Writing compilers/parsers is defiantly not for the faint-hearted...if you haven't done it before ....there is a learning curve that makes Everest look like a stroll around the park.
If you need some guidance I can help.,,,,but maybe you have some luck with a third-party package....who knows ?
The A-B PLC5 was so ubiquitous that several controls companies offered software 'migration' routines that converted logic to their platforms, with all sorts of caveats, warnings and exemptions about conversion efficiencies'. The meaning was clear, the straightforward stuff gets 'translated', the remainder needs human brain power to work it out.

But that was for a very popular brand/model past the end of its life span when enough market opportunity existed that it warranted the investment in migration utility.