Expression Evaluator¶

Function

Calculates the result of an expression with integers, decimals, numeric variables, string variables (only for string comparisons), arithmetic and Boolean operators and a set of functions.

Properties

Properties	Description
Expression	Expression to be calculated. Note if the expression does not follow the correct syntax, the converter will not perform the calculation.
Mode	Read: read (link from source to parent) Write: write (link from parent to source) Read/write: read and write (link from parent to source and vice versa)

Source

One or more variables, identified by a placeholder with an index number, with the following format {index}. The index number is progressive, must be an integer greater than zero ({0}).

The placeholders can appear in any order in the expression.

Valid literal values

Boolean: true and false.
Integers
Decimals. The decimal separator must be a point.
Hexadecimal numbers with prefix “0x” (e.g. 0xff)
Text, delimited by double quotation marks (e.g. string)

Note

double quotation marks repeated twice ("") are interpreted as an escape sequence.

Valid Operators

Arithmetical: +, `` -`` , *, `` /`` , % and unary operator -
Bitwise: &, | , ^,``~``
Shift: <<, >>
Logics: &&, ||, !
Unary casting of (<data_type>) type
Comparison <, <=, >, >=, ==, !=

Note

all the comparison operators are applicable both to numeric data, and to DateTime and Duration data.

Note

the operators: == and != are also applicable to String and LocalizedText data types.

Datatype Conventions

Literal integers are Int32.
Decimal literals are Double.
Numerical values are considered to be Int32.
The following literals: true and false are interpreted as Boolean.
The / operator always returns a Double value.
The % operator generates an exception when there is division by modulo zero.
The % operator accepts Float and Double operands.
All the functions return a Double value except for the sign function, which returns an Int32 value.
The unary casting operator accepts the following datatypes:
- bool, Boolean
- sbyte, SByte
- short, Int16
- int, Int32
- long, Int64
- byte, Byte
- ushort, UInt16
- uint, UInt32
- ulong, UInt64
- float, Single
- double, Double

Parentheses

The expression can contain an unlimited number of parentheses, correctly opened and closed.

Available Functions

These mathematical functions are available:

Function	Calculated value	Example
`max`	Maximum of two values	`max ({0}, {1})`
`min`	Minimum of two values	`min ({0}, {1})`
`avg`	Average of given values	`avg ({0}, {1})`
`abs`	Absolute value	`abs ({0})`
`trunc`	Integer part of a decimal number	`trunc ({0})`
`ceil`	Approximated value by excess	`ceil (({0} + {1})/2)`
`floor`	Approximated value by defect	`floor (({0} + {1})/2)`
`round`	Approximation to the nearest integer	`round (({0} + {1})/2)`
`sqrt`	Square root	`sqrt ({1})`
`sign`	0 if the argument value is greater than zero 1 if the argument value is less than zero	`sign ({1})`

Output

The resulting value of the expression.

Logical representation

The following image illustrates an example of a logical conversion in the advanced dynamic link editor.