Expression Evaluator#

The system comes with a flexible expression evaluator engine which is used to dynamically calculate values. The expression evaluator is used in different parts of the application, specifically in the following objects:

Maintenance Management, for defining counter expressions in Usage or UsageAndTimeBased activities.
Printable Document, for defining Printable Document Contexts of type Expression.
Recipe, for defining Sub Recipe parameter maps.

Warning

This engine is not used in the Expression Evaluator Automation Controller Core Task, which uses a separate but equally powerful engine. Please consult the documentation for that particular engine in Task - Expression Evaluator.

This section describes the syntax of the expression evaluator.

Info

The expression evaluator is not case sensitive.

Operators#

Operator	Description	Usage	Result Type
`&&`	AND logical operator	expression && expression	Boolean
`and`	AND logical operator	expression and expression	Boolean
`or`	OR logical operator	expression or expression	Boolean
\|\|	OR logical operator	expression \|\| expression	Boolean
`not`	NOT logical operator	not expression	Boolean
`!`	NOT logical operator	!expression	Boolean
`+`	Adds the value of two expressions. If the result of one of the expressions is a string, the result will be a concatenation of the two strings.	expression + expression	Numeric / String
`*`	Multiplies the value of two expressions	expression * expression	Numeric
`-`	Subtracts the value of two expressions	expression - expression	Numeric
`/`	Divides the value of two expressions	expression / expression	Numeric
`==`	Tests if the values of two expressions are equal	expression == expression	Boolean
`=`	Tests if the values of two expressions are equal	expression = expression	Boolean
`<`	Tests if one expression is less than another expression	expression < expression	Boolean
`>`	Tests if one expression is greater than another expression	expression > expression	Boolean
`<=`	Tests if one expression is less than or equal to another expression	expression <= expression	Boolean
`>=`	Tests if one expression is greater than or equal to another expression	expression >= expression	Boolean
`!=`	Tests if one expression is different from another expression	expression != expression	Boolean
`<>`	Tests if one expression is different from another expression	expression <> expression	Boolean
`%`	Module function that returns the remainder after division	expression % expression	Numeric
`^`	Raises one expression to the power of another (power function)	expression ^ expression	Numeric

Table: Expression evaluator - operators

Functions#

Mathematical#

Function	Description	Usage	Result Type	Example
`abs`	Absolute value	abs(expression)	Numeric	abs(-3)=3
`log`	Returns the natural (base e) logarithm of a given number	log(expression)	Numeric	log(e) = 1
`log(x,y)`	Returns the logarithm of a specified number on a given base number	log(expression number,expression base)	Numeric	log(1000,10) = 3
`log10`	Returns the base 10 logarithm of a given number	log10(expression)	Numeric	log10(100) = 2
`exp`	Return e raised to the power of a given number	exp(expression)	Numeric	exp(1) = e
`cos`	Returns the cosine of a given number	cos(expression)	Numeric
`sin`	Returns the sine of a given number	sin(expression)	Numeric
`tan`	Returns the tangent of a given number	tan(expression)	Numeric
`random`	Returns a random number between a minimum and maximum value	random(minValue,maxValue)	Numeric

Table: Expression evaluator - mathematical functions

String#

Function	Description	Usage	Result Type	Example
`&`	Concatenates two strings	expression str1 & expression str2	String
`substring`	Returns a new string that is a substring of another string. The substring begins at the specified given index and extends up to the given length	substring(exp string, exp startIndex) or substring(exp string, exp startIndex, exp length)	String	substring("alfa",1,2) = "lf "
`length`	Returns the length of a String	Length(expression) or expression.Length	String
`lower`	Converts a String to lower case	Lower(expression)	String
`upper`	Converts a String to upper case	Upper(expression)	String
`replace`	Replaces a string within a string	Replace(exp string, exp find, exp replace)	String
`contains`	Checks if a String contains a substring	Contains(exp string, exp substring)	String
`token`	Gets a specific token within a string	token(exp string, exp separator, exp tokenNumber)	String
`trim`	Trims a given string	Trim(exp string)	String

Table: Expression evaluator - string functions

Flow Control#

Function	Description	Usage	Result Type	Example
`if`	Tests a condition, and returns one expression if the condition is true and another one if the condition is false	if expression then expression else expression	Object
`if`	Tests a condition, and returns one expression if the condition is true and another one if the condition is false	if(condition,thenclause,elseclause)	Object	if(10 * 30; 100; 20) = 20
`in`	Verifies if a value is contained in a list	exp value in exp list	Boolean	10 in array(1,6,7,10) = true
`decode`	Resolves a value for a list of possibilities	decode(exp value, exp test1, exp result1, ..., exp testN, exp resultN, exp default)	Object	decode("a", "b", 10, "a", 20, 30) = 20

Table: Expression evaluator - flow control functions

Variables and Objects#

Function	Description	Usage	Result Type	Example
`array`	Creates an array	array(expression 1, ... , expression N)	Object[]
`arraysize`	Returns the length of an array or of a string	arraysize(expression)	Numeric
`new`	Creates a new instance of a business object	new Object Name()	Object	New Material()
$	Gets the value of a variable supplied as an input for the runtime	$variableName	Object	$ xml $1Param * 3
$	Gets the value of a variable supplied as an input for the runtime	$[expression]	Object	$ [$vName] $ ["Material Type"]
`.`	Path navigator	expression.(expression)	Object	$ Material.("Name")
`.`	Path navigator	expression.expression	Object	$ Material.Step.Name

Table: Expression evaluator - variables and objects functions

Warning

When the variable name contains a number or a special character and you want to use an expression, you must reference it like this: $["1Param"] * 3. See the following example:

The variables used in these examples must be supplied as an input to the expression evaluator engine. In this case, no specific Material is being accessed, only the variable passed on to the engine as an input.

Environment#

Function	Description	Usage	Result Type
`host`	Gets the current host name	host	String
`domain`	Gets current user domain name	domain	String
`env`	Gets the value of a given environment variable	env(exp variable name)	String
`now`	Gets the current date and time (c# -> DateTime.Now)	now	DateTime
`pid`	Gets the application Process ID	pid	Numeric
`user`	Gets the current user name	user	String

Table: Expression evaluator - environment functions

Constants#

Constant	Description	Usage	Result Type	Example
`false`	Returns false	false	Boolean	false
`true`	Returns true	true	Boolean	true
`pi`	Returns the value of the PI constant	pi	Numeric	pi
`null`	Keyword that represents the null value	null	Null	null
`e`	Represents the natural logarithmic base	e	Float	e

Table: Expression evaluator - constants