Automation Engine Script Guide > Ordered by Function > Script Structure and Processing > :IF... :ELSE... :ENDIF

:IF... :ELSE... :ENDIF

Script Statements: They analyze an expression and depending on the result, they run statements.

Syntax

:IF Condition
[Statements]
[:ELSE]
[Other Statements]
:ENDIF

Syntax	Description/Format
Condition	A mathematical expression that consists of script literals, script variables, script functions or numbers with the possible results "True" or "False"
Statements	One or more statements that will be executed when the condition is "True" Format: script statement
Other Statements	One or more statements that will be executed when the condition is "False" Format: script statement

Comments

An IF statement is a control structure that you can use to process scripts depending on the result that a condition supplies. A condition is a logical expression.

When the condition applies (it is true), the statements are executed.

When the condition does not apply (it is false), the :ELSE statements are processed. When the IF block does not contain an :ELSE branch, it continues with the next line that follows the :ENDIF statement.

IF blocks can also be nested. The nesting depth is not limited.

IF blocks do not necessarily include ELSE branches.

When strings exceed 1024 characters, a difference in characters beyond the 1024th character will not be recognized by an :IF statement in the script. The comparing algorithm only checks the first 1024 characters of a string.

Using an OR keyword

To link a condition to several values or to link several individual conditions, you use OR as the keyword.

Conditions show the following structure:

ValueComparison operatorComparison Value[OR Comparison Value...]

For example:
:IF &DEP# = "EDP" OR "AE"

You can use up to 13 ORs in a condition.

Comparison operators

A condition contains one of the following comparison operators:

Operator	Short form	Rule
=	EQ	This expression is "True" if at least one of the comparison values equals the Value.
<>	NE	This expression is "True" when none of the comparison values equals the Value.
<	LT	This expression is "True" if one comparison value corresponds to the defined condition.
>	GT
<=	LE
>=	GE

A numerical comparison takes place when both comparison values of a condition have a numerical value (data types signed, unsigned or float). A string comparison takes place in all other cases. Note that leading zeros are only ignored in numerical comparisons.

The following condition supplies "True":

:IF "0" = "0"

An alpha-numeric comparison takes place when there are no numerical values.

The following condition supplies "False":

:IF "0" = "abc"

Script lengths are not checked during the comparison process. The following condition supplies "True" because "S" comes before the "U" in the alphabet.

:IF "Smith" < "AE"

Note that you must define the script variables that you use in a condition beforehand.

Conditions that include the keyword OR several times can show various behaviors depending on the operator.

For example:
In the following example, one of the values must apply in order to meet the condition.

:IF &WD# = "MON" OR "TUW" OR "WED"

The following condition is only met if the variable does not comply to any of the three values.

:IF &WD# <> "THU" OR "FRI" OR "SAT"

Trailing Blank Spaces Are Not Considered

Trailing blank spaces are not considered in string comparisons. Therefore, blank strings always are equal independent on their length.

For example:

:set &a= 'a '
:set &b= 'a'

:if &a = &b
:print 'true'
:endif

In this case, comparison of &a with &b would return true as trailing blanks are eliminated before the comparison.

Examples

The following examples show different ways of defining a condition. The examples 1 to 3 put a script variable into relation with one or more comparison values. The fourth example uses the return code of a function.

:IF &USER# = "TSOS"
!...
:ENDIF

:IF &DAT1# = &DAT2# OR " "
!...
:ENDIF

:IF &USER# <> "TSOS" OR "SERVICE" OR SYS_USER_NAME()
!...
:ENDIF

:IF GET_ATT(OO) = "J"
!...
:ENDIF

Script element	Description
:SWITCH... :CASE... :ENDSWITCH	It verifies whether the value of a variable complies with certain values and depending on the result, it runs various statements.
:WHILE... :ENDWHILE	This is used to define a loop for the repeated execution of script elements.