Evaluation functions are ubiquitous in scripts but rare in compiled languages because it's far easier to carry out the evaluation of a string with an interpreter. This creates problems if you're writting an interactive application, particularly a mathematical one, as you're liable to want the user to enter equations, etc.

This class overcomes that problem by providing a method for a VB application to evaluate a string.

It's based on the published Microsoft code with additions to allow the recognition of more variables and functions.

The class is called **eval** which has a single method of the same name, **eval**.

The class recognises the variables **a, b, c, d, l, m, x** and **y**, (although only **x** is available in the demonstration), and the constants **pi** and **e** as well as the usual operators, trig. and inverse trig. functions, the hyperbolic functions, log_{2}, (**log2**), and log_{10}, (**log10**).

[Last update: 10/11/2018]