Operators
Template:SideTOC Operators are the base commands each programming language is built on. They provide ability to perform basic mathematical and logical operations.
Requirements
To understand this article, you should read the following articles:
Terms
- Operand
- An operand is any value given to an operator.
- Expression
- An expression is basically any code that returns a value. Read Expression for more information.
- Unary Operator
- An unary operator is an operator that requires only one operand.
- Unary operation:
operator expression
- Binary Operator
- A binary operator is an operator that requires two operands.
- Binary operation:
expression operator expression
Operators
Assignment Operators
Assignment operators are used to assign values to a variable. OFP's scripting language provides only one assignment operator.
Assignment:
identifier = expression
Example 1:
a = b
You might think that this operator compares a and b, but that is not the case. = simply sets the left value to be the right one. There don't exist any other assignment operators like +=, -= etc., that can be found in other programming languages.
Example 2:
a = b*c
Arithmetic Operators
Remember arithmetic operations from school? These work just the same way.
All operands of arithmetic operations must be Numbers. Arithmetic operations always return a Number.
| Operator | Name | Example |
|---|---|---|
| - | Negation | -a, +-a, -+a |
| + | Posation | +a |
| ( | Bracket | (expression) |
| Operator | Name | Example |
|---|---|---|
| + | Addition | a + b |
| - | Subtraction | a - b |
| * | Multiplication | a * b |
| / | Division | a / b |
| % | Modulo | a % b |
| mod | Modulo | a mod b |
| ^ | Raise to the power of | a ^ b |
Modulo returns the remainder of the division a / b.
See also: Math Commands
Logical Operators
Logical operators evaluate Boolean values. All operands of logical operations are Booleans.
A logical operation always returns a Boolean.
| Operator | Name | Example |
|---|---|---|
| ! | Not | !a |
| not | Not | not a |
The Not-operator always returns the inverse Boolean value. If a Boolean a is true, !a returns false and vice versa.
| Operator | Name | Example |
|---|---|---|
| && | And | a && b |
| and | And | a and b |
| || | Or | a || b |
| or | Or | a or b |
- And only returns true if both operands are true
- Or returns true if one or both operands are true
There is no Xor, Nor and Nand operator. Those can be simulated using the basic operators though:
| Name | Combination |
|---|---|
| Xor | ((a || b) && !(a && b)) |
| Nor | !(a || b) |
| Nand | !(a && b) |
- Xor returns true if exactly one of both values is true
- Nor returns true if none of both values is true
- Nand returns true if not both values are true at the same time
Comparison Operators
Comparison operators compare two values. Operands of comparisons may be of type Number, Side, String, Object, Group, Structured Text, Config, Display or Control for == and != , and Number for < > >= <=
Comparisons always return a Boolean: true if the comparison matches, false if not.
| Operator | Name | Example |
|---|---|---|
| == | Equal | a == b |
| != | Not equal | a != b |
| < | Less than | a < b |
| > | Greater than | a > b |
| <= | Less or equal | a <= b |
| >= | Greater or equal | a >= b |
Array Operators
The scripting language offers own operators to deal with arrays. All operands, of course, have to be of type Array.
The return value of an array operation is an Array.
| Operator | Name | Example |
|---|---|---|
| + | Copy | +myArray |
Normally arrays are assigned by reference. That means, if you assign array a to array b and change a afterwards, also b is changed. Use the copy operator to avoid this otherwise useful feature.
Example 1:
_arrayA = [1,2]; _arrayB = _arrayA; _arrayA set [0,5]; _arrayA => [5,2] _arrayB => [5,2]
Example 2:
_arrayA = [1,2]; _arrayB = +_arrayA; _arrayA set [0,5]; _arrayA => [5,2] _arrayB => [1,2]
| Operator | Name | Example |
|---|---|---|
| + | Concatenation | myArray1 + myArray2 |
| - | Removal | myArray1 - myArray2 |
- + adds the second operand on the end of the first operand
- - removes all elements of the second operand from the first operand
Example 1:
_arrayA = [1,2]; _arrayB = [3,2,4]; _arrayC = _arrayA + _arrayB; _arrayC => [1,2,3,2,4]
Example 2:
_arrayA = [1,2,3,2,4]; _arrayB = [2,3]; _arrayC = _arrayA - _arrayB; _arrayC => [1,4]
String Operators
The scripting language offers one single string operator to concatenate strings. Both operands must be Strings.
The return value of a string operation is a String.
| Operator | Name | Example |
|---|---|---|
| + | Concatenation | myString1 + myString2 |
- + adds the second operand on the end of the first operand
Example:
_stringA = "Hello "; _stringB = "World!"; _stringC = _stringA + _stringB; _stringC => "Hello World!"
Rules of Precedence
| Prece- dence |
Type of Operator | Associativity |
|---|---|---|
| 11 |
Nular operators (commands with no arguments):
Other:
|
Left-to-right |
| 10 |
Unary operators (commands with 1 argument):
Unary plus and minus: Array copy operator: Logical NOT operator: |
Left-to-right |
| 9 |
The new select operator: |
Left-to-right |
| 8 |
Power operator: |
Left-to-right |
| 7 |
Number multiplication, division and remainder: Config access: atan2 command: |
Left-to-right |
| 6 |
Number addition and subtraction: Array addition and subtraction: String addition: min and max commands: |
Left-to-right |
| 5 |
else operator: |
Left-to-right |
| 4 |
Binary operators (commands with 2 arguments):
switch colon operator: |
Left-to-right |
| 3 |
Number comparison: String comparison: Group, Side, Object, Structured Text, Config, Display, Control or Location comparison: Config access: |
Left-to-right |
| 2 |
Logical AND operator: |
Left-to-right |
| 1 |
Logical OR operator: |
Left-to-right |