If…Else Statement
Runs a sequence of statements because of a condition.
Syntax
Block construct
If condition [ Then ]
    [ statements ]
[ Else If else_if_condition [ Then ]
    [ else_if_statements ] ]
…
[ Else
    [ else_statements ] ]
End [ If ]
One-line construct
If condition Then statement [ Else else_statement ]
Parts
condition- Mandatory Boolean expression.
 Then- Optional in the block construct
 - Mandatory in the one-line construct
 statement(s)- Run only when 
conditionis true.. - Optional in the block construct, one or more statements.
 - Mandatory in the one-line construct, a one-line statement.
 Else If- Optional keywords that you can use again and again.
 else_if_condition- Mandatory after 
Else If, a Boolean expression calculated only whencondition(orelse_if_conditionbefore this one) is false. else_if_statements- Optional one or more statements, run only when 
elseif_conditionis true. else_statement(s)- Optional one or more statements, run only after 
conditionand all ofelse_if_condition(s)are false. End- Completes the block construct.
You can also use 
End If. 
Instructions
Block construct
TODO
When If…Else becomes too long, you can replace it with a Select…Case Statement.
One-line construct
You can use the one-line construct for short, easy tests. There are only 12 statements that you can use with this construct.
Note:
You cannot nest the one-line constructs of If…Then.
This is because it can cause problems when some of the statements have Else while other statements do not.
Changes in syntax with @Option
There are three areas where you can change the syntax of the statement:
@Option If Thenand@Option If@Option If End@Option End Blockand@Option End
See @Option Directive for more information.
Examples
If x = 1 Then
    Call First
End If
If x = 1 Then
    Call First
Else
    Call Other x
End If
If x = 1 Then
    Call First
Else If x = 2 Then
    Call Second
Else If x = 3 Then
    Call Third
Else
    Call Other x
End If
If x = 1 Then Call First
If x = 1 Then Call First Else Call Other x