README.md

Description

This module can be used to parse a mathematical expression given as a string. The result is just a double value, which can be used for anything you'd like to.

More Info

A string containing an expression. Spaces between operators and operands are ignored. The following operators are supported:

• exponentiations (^)

• multiplications (*)

• divisions (/)

• modulus (%)

• additions (+)

• substractions (-)

Besides it's possible to use some built-in functions, putting parameters between braces:

• sin, asin, cos, acos, tan, atan

• int (returns integer part)

• frac (returns decimal part)

• log (logarithm with base 10)

• ln (natural logarithm with base e)

• abs (absolute value)

• sign (returns -1, 0 or 1)

• rnd (random number between 0 and param)

• sqrt (square root)

You can define your own functions. These functions are implemented in BasicFunctions.

I haven't implemented variable support, because the best way to do so depends on how you're going to use this code. The ReadVariable-function is called when the value of a variable is needed. It's your own job to implement it.

Last but not least sub-expressions are supported by encapsulating them with braces.

Example (showing some features):

12 * (14-36 ^ (-sin(-4*sqrt(18)))) / (15 * rnd(4) +1)

Just call ParseExpression("1+1") to see what happens.

Variable support isn't implemented.

A double value containing the result.

Operator precedence:

1. Functions and variables

2. Sub-expressions

3. Exponentiations (^)

4. Multiplications (*) and divisions (/)

5. Modulus (%)

6. Additions (+) and substractions (-)

Submitted On	2002-09-09 13:19:04
By	Mark van Cuijk
Level	Intermediate
User Rating	5.0 (25 globes from 5 users)
Compatibility	VB 4.0 (32-bit), VB 5.0, VB 6.0
Category	Math/ Dates
World	Visual Basic
Archive File	Expression128807992002.zip