The following constructs are available for controlling program flow.
If {expression} Then {statements1} Else {statements2}
Evaluates the If
expression and, if true, executes the Then
statements. If false, the Else
statement are executed, the Else
part is optional - statements are executed until the end of the line.
If {expression1}
{statements1}
Else If {expression2}
{statements2}
Else If {expression3}
{statements3}
Else
{statements4}
EndIf
This form of the If statement allows for more than one line of statements. The Else If
and Else
parts are optional. The Else
part is executed only if none of the If
or Else If
expressions were true.
While {expression}
{statements}
Wend
A While loop continues executing until {expression}
evaluates to False
. {expression}
is evaluated at the start of each loop.
For {variable}={initalvalue} To {finalvalue} Step {step}
{statements}
Next
A For/Next loop first assigns {initialvalue}
to {variable}
and then starts looping. The loop continues until {variable}
reaches {finalvalue}
and then terminates. In each loop, the value {step}
is added to {variable}
. If a step value is omitted, a default value of 1 is used.
This form of the For/Next loop allows you to iterate over all objects of a custom type.
Repeat
{statements}
Until {expression}
A Repeat loop continues executing until {expression}
evaluates to True
. {expression}
is evaluated at the end of each loop.
Repeat
{statements}
Forever
A Repeat/Forever loop simply executes {statements}
until the program ends, or an Exit
command is executed.
Select {expression}
Case {expressions1}
{statements1}
Case {expressions2}
{statements2}
Default
{statements3}
End Select
First the Select
expression is evaluated. It is then compared with each of the Case
expression lists. If it matches a Case
, then the statements in the Case
are executed.
If the Select
expression matches none of the Case
expressions, the statements in the optional Default
section is executed.
The Exit
command may be used to break out of any For...Next
, While...Wend
, Repeat...Until
or Repeat...Forever
loop.
Blitz also supports the Include
command. Include allows source code from an external file to be compiled as if it were part of the main program. Include must be followed by a quote enclosed filename. For example...
Include "anotherfile.bb"
Include allows you to break your program up into smaller, more manageable chunks.