Functions
Built-in Functions
The framework includes a set of already implemented functions.
| Name | Description | Usage | Result |
|---|---|---|---|
| Abs | Returns the absolute value of a specified number. | Abs(-1) | 1d |
| Acos | Returns the angle whose cosine is the specified number. | Acos(1) | 0d |
| Asin | Returns the angle whose sine is the specified number. | Asin(0) | 0d |
| Atan | Returns the angle whose tangent is the specified number. | Atan(0) | 0d |
| Ceiling | Returns the smallest integer greater than or equal to the specified number. | Ceiling(1.5) | 2d |
| Cos | Returns the cosine of the specified angle. | Cos(0) | 1d |
| Exp | Returns e raised to the specified power. | Exp(0) | 1d |
| Floor | Returns the largest integer less than or equal to the specified number. | Floor(1.5) | 1d |
| IEEERemainder | Returns the remainder resulting from the division of a specified number by another specified number. | IEEERemainder(3, 2) | -1d |
| Ln | Returns the natural logarithm of a specified number. | Ln(1) | 0d |
| Log | Returns the logarithm of a specified number. | Log(1, 10) | 0d |
| Log10 | Returns the base 10 logarithm of a specified number. | Log10(1) | 0d |
| Max | Returns the larger of two specified numbers. | Max(1, 2) | 2 |
| Min | Returns the smaller of two numbers. | Min(1, 2) | 1 |
| Pow | Returns a specified number raised to the specified power. | Pow(3, 2) | 9d |
| Round | Rounds a value to the nearest integer or specified number of decimal places. The mid number behaviour can be changed by using ExpressionOptions.RoundAwayFromZero during construction of the Expression object. | Round(3.222, 2) | 3.22d |
| Sign | Returns a value indicating the sign of a number. | Sign(-10) | -1 |
| Sin | Returns the sine of the specified angle. | Sin(0) | 0d |
| Sqrt | Returns the square root of a specified number. | Sqrt(4) | 2d |
| Tan | Returns the tangent of the specified angle. | Tan(0) | 0d |
| Truncate | Calculates the integral part of a number. | Truncate(1.7) | 1 |
It also includes other general purpose ones.
| Name | Description | Usage | Result |
|---|---|---|---|
| in | Returns whether an element is in a set of values. | in(1 + 1, 1, 2, 3) | true |
| if | Returns a value based on a condition. | if(3 % 2 = 1, 'value is true', 'value is false') | 'value is true' |
| ifs | Returns a value based on evaluating a number of conditions, returning a default if none are true. | ifs(foo > 50, "bar", foo > 75, "baz", "quux") | if foo is between 50 and 75 "bar", foo greater than 75 "baz", otherwise "quux" |
You can use comma (,) or semicolon (;) as argument separator.
If DecimalAsDefault is used all functions will cast the arguments to decimal.
Custom Functions
Custom functions are created using the ExpressionFunction delegate. The parameters are Expression instances that can be lazy evaluated.
expression.Functions["SecretOperation"] = (args) => {
return (int)args[0].Evaluate() + (int)args[1].Evaluate();
};
Using Event Handlers
You can also use event handlers to handle functions.
expression.EvaluateFunction += delegate(string name, FunctionArgs args)
{
if (name == "SecretOperation")
args.Result = (int)args.Parameters[0].Evaluate() + (int)args.Parameters[1].Evaluate();
};
Case Sensitivity
See case_sensitivity for more info.