Use relational operators to evaluate conditions.

Table 49. Relational Operators
Operator Meaning
== Check for equal to
>= Check for greater than or equal to
> Check for greater than
<= Check for less than or equal to
< Check for less than
!= Check for not equal to

not Conditions

Negate the conditions using the keyword not.

not Condition

Example: not Condition

jsonValue v
if not v:IsNull then
// ...
endif

jsonObject o
if not o:IsEmptyOrNone() then
// ...
endif

Logical Operators

Combine conditions using logical operators.

Condition Logical Operator Condition
Logical Operator Meaning
and Both conditions must be met for the condition to be true.
or At least one of the conditions must be met for the condition to be true.

Example: Logical Operators

program
  section globals
     int32 x
  endsection
  int32 a = 0
  if ( a == 1 and x < 0 ) or ( a > 0 ) then
    //code
  endif
endprogram

if Conditions

Use an if condition to execute code that is linked to a condition.

The syntax is:

if Condition1 then
    // Code
elseif  Condition2 then
    // Code
else
    // Code 
endif
  • An if condition always starts with an if part and finishes with an endif part.
  • The else branch and the endif branches are optional.
  • You can use any number of elseif conditions.
  • A line break must follow then.
  • The if / elseif / else code block cannot contain any nested if statements.

Example: if Condition

program
  section globals
    int32 a
    int32 b
    real64 c
  endsection
  
  if a == 1 then
    b = 5 * a
    c = sin(PI)
  elseif a == 2 and b == 2 then
    b = 0
    c = cos( PI )
  else
    b = -1 
  endif 
endprogram