I think the problem is that you can't parse this with regular expressions. You need a more advanced parser. This is because regular expressions cannot solve the matching parentheses problem (given a string of left and right parentheses, determine if the parentheses match). In this case, the regular expression replaces one implied multiplication (the first one it sees), and so it fails when there is another one. You could modify it to replace n implied multiplications, but it would break for n + 1.
The solution is to write an actual parser. I don't know the best way to do this. Perhaps the one that we use for sympify can be adapted. This is actually the same problem as with the LaTeX parser. What's the best way to write an extensible parser? Can the AST module perhaps be used (or does that only work for Python syntax)? Aaron Meurer On Wed, Nov 23, 2011 at 10:20 AM, gsagrawal <[email protected]> wrote: > There are some issues in regex expressions of mathematica. > See below cases > > k="(h+g)(l+m)r" > print mathematica(k) > output -> (g + h)*(l + m) > k="r(h+g)(l+m)" > print mathematica(k) > output ->Exception > > i am new to regex so can anyone provide the correct regex expressions  ? > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
