ToExpression[] support

[darvin]

In[194]:= ToExpression["3 + x^2 - 4"]                                                            

                   2         2           2         2
Out[194]= {{-1 + a1 , -1 + b1 }, {-1 + a2 , -1 + b3 }}

In[195]:= ToHeldExpression["3 + x^2 - 4"]                                                        

                    2
Out[195]= Hold[3 + x  - 4]

In[196]:= ?ToExpression                                                                          
ToExpression[input] gives the expression obtained by interpreting strings or boxes as 
    Wolfram Language input. 
ToExpression[input, form] uses interpretation rules corresponding to the specified form. 
ToExpression[input, form, h] wraps the head h
     around the expression produced before evaluating it. 

[mmatera]

It would be useful also for the new version of iwolfram.