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Conditions
To
execute a sequence of instructions under some conditions,
you can use conditions (surprising...). This is
the same syntax as other Basic-like languages.
If condition1 Then
instructions1
EndIf
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First, condition1 is evaluated at the run-time,
and if condition1 is true, instructions1
will be executed. If condition is false, the program
continue its execution after the EndIf.
You can also use keywords as Else
and ElseIf.
If a condition after If
is false, the jump won't be on EndIf,
but on Else
or ElseIf.
If condition1 Then
instructions1
Else
instructions2
EndIf
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Here, if condition1 is true, instructions1
will be executed, otherwies it will be instruction2.
If the execution of instruction2 has also
got a condition condition2, you can use ElseIf
like that :
If condition1 Then
instructions1
...
ElseIf condition2 Then
instructions2
...
EndIf
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If condition1 and condition2 are false,
neither instructions1 or instruction2
will be executed.
You can set a sequence of ElseIf
and eventually end with a Else
to have the case if all the other conditions are
false.
If condition1 Then
instructions1
...
ElseIf condition2 Then
instructions2
...
ElseIf condition3 Then
instructions3
ElseIf condition4 Then
instructions4
Else
instructions5
EndIf
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Here, instructions5 will only be executed
if all the conditions before are false.
Expression of conditions
A
condition is an expression which returns TRUE
or FALSE.
A condition can be done with the following operators
:
| = |
Is equal to |
| <> |
Is not equal to |
| < |
Less than |
| > |
Greater than |
| =< or <= |
Less or equal to |
| >= or => |
Greater or equal to |
You can use the following logic operators :
So you can get one condition in one boolean expression.
The And operator has priority on Or.
Brackets are used as usual You can use them for
priorities :
is different of
The two elements to compare must be of the same
type. A variable to be compared must be declared
(implicitly or not).
If you have defined a type of variable and you want
to compare variable of this type, the only operators
are equal "=" and non-equality
"<>". Two variables with a user-defined
type (it means defined by you) are equal only if
all the fields of the variables are equal.
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