Is there any Function or Functional Block available to evaluvate a string as shown below

Result:BOOL;

Input_Expression:STRING;

Input_Expression := '1 OR 0 AND 1 OR 0';

Result := ( Should give the result of the Input_expression )

Thanks in advance.

Rajesh G

What you are talking about is an interpreter.

This is a good project for students in first year computer science curriculum.

I don't believe there is an interpreter built into CoDeSys but that doesn't mean you couldn't write one. Although, I can't see the reason for it.

I created a function which will do the process, but the problem is i need to reduce the process time, If the Expression length is big,

Find the attached code for reference.

Equation_Processing_4.pro [283.73 KiB]

in the open source library oscat you can find code for a similar expression engine 'exec' this could be modified quickly to evaluate your statements.

pls get the library at w www.oscat.de w

I tried the Exec function which can handle only one operator, But in our case user can enter an lenghty expression with more than one operator( AND & or OR |). I hope the exec function will not help us.

If possible let me know any algoritum to do Expression Evaluvation.

Thanks and Regards

Rajesh G