Switch statements

Switch statements in ASIL may seem strange. That's because you can vary how much of a comparison is done in the compilation stage.

• Your basic switch statement
• A switch with more comparison options
• A switch that acts like an if/else if

Your basic switch statement

This is closest to what C++ and C# have.

:::text
switch i%
  case 3
    ' Handle case 3
    break ' Fall through not allowed if this case does something

  case 5
  case 6 ' Fall through allowed because case 5 is empty
    ' handle cases 5 and 6
    break

  else ' All other cases
    ' handle the default case

A switch with more comparison options

You don't need to have all the comparisons in a switch be on equality. ASIL allows for an interrupted comparison. In both of the switch statements below, ASIL will put the pieces together.

:::text
switch i%
  case < 3
    ' handle all cases less than 3
    break

  else
    ' handle all other cases

switch f% >
  case 5
    ' Handle all cases greater than 5
    break

  case 3 ' Since the switch started with >, all subsequent cases must be less than the previous case.

  else
    'Handle all remaining cases

A switch that acts like an if/else if

If nothing follows the switch keyword, then each case must have the entire condition.

:::text
switch
  case i% < 3
    ' handle all cases where i% is less than 3

  case f# > 3.5
    ' handle F3 being more than 3.5

  else
    ' handle everything else

[Will Pittenger]

I considered making switch a complex statement, but ended up building it into the language like I did with if/then/else. Made for a more flexible syntax.