Finding matched parentheses

[dfepstein at comcast.net]

On second thought : 


function offsetPair a,b,str -- str cannot be more than one line 
   -- returns first instance of char a && "matching" instance of char b in str, or 0 if no a or empty if no match 
   put offset(a,str) into ca 
   if ca = 0 then return 0 
   put numToChar(7) into char 1 to ca of str 
   set lineDelimiter to a 
   set itemDelimiter to b 
   repeat with i = 1 to the number of items in str 
      if i = the number of lines in item 1 to i of str then return ca && ca+length(item 1 to i of str) 
   end repeat 
   return empty 
end offsetPair