Logical vs arithmetic expressions

I need an expression parser as you have developed.  I also need to handle logical expressions.

so I must handle  A=1.25 + B*(q+4.5). This is an arithmetic assignment.
 I must also handle IF xxy = A=1.25 + B*(q+4.5) then
I have some questions. Can we take this offline and you email me at  prf51 atsign videotron.ca

Regards, Pierre.