replacing characters within a delimited string (i.e. " quotes)

hello experts

Her eis my problem, that I have been struggling with. I am writing a library (SO) on soalris to be used by some 3rd party application. It accepts calls to internal procedures using its own language given you pass it through their c function, which is run_code(arg);

So I have to pass in the internal call to this function run_code(arg). Thus I have a line that looks like

run_code(internalFunction/SubRoutine("arg1", "arg2", ..., "arg n"))

The problem is if any of the args to the internal function call have any of the following characters in its string (i.e " quote, ' single quote, \ backslash, or ) right parenthesis) then it has a problem. The run_code function, which is vendor propietary can not handle these characters, thus I need to replace any of these special characters with "entity refernece" and then replace it once we get through this wall (run_code)... Thus I want to do the following....

Given this call...

run_code(Class/Method("my argument with special chars is: )'"\", "next arg", "last arg"))

needs to be turned into this

run_code(Class/Method("my argument with special chars is: #rpar;#apos;#quot;#bksl;", "next arg", "last arg"))

were
) -> #rpar;
\ -> #bksl;
' -> #apos;
" -> #quot;

I have a wonderful substring replacement function that I wrote, that would work great if I could break this into tokens successfully... replacing the single quot and backslash really aren't a problem because they are not special within the function call itself... I can just do a substring replacement for single quot and backslash for the whole string... the problem is the " double quote and ) right parenthesis...

What I need is something that will read this string... and give me a substring that I can do replacements on, were the substring is delimited by "...", or "..."))
that is give me a sub string if it begins with " has some stuff and is followed by ", " (i include comma b/c there may be " in the argument) or " ... ")) and 2 parenthesis followed by no more characters or white space... (signaling end of call.. i.e. last argument)

Sorry if that is confusing.. it is confusing me too.. that is why I need help. In simple words I need a way to replace the following character " ' ) and \ when they are used as characters in the argument portion of the call below.

run_code(Class/Method("my argument with special chars is: )'"\", "next arg", "last arg"))

Any help, thoughts, or ideas...?? pseudo code, examples greatly welcomed... This should be highly flexible in case the user

Thanks in advance

rechard