Takes a variable number of conditional statements to compare against a single source

Description:

Traditional Select / Case / End Select conditional block(s) to assist with flow control of a procedure using a single source comparison.

These conditions in an If / End If block can take two forms:

1. If Field/Expression (Boolean)
2. If Field/Value Condition Field/Value/Expression (Condition)

When Boolean, no value is specified on the Select line. Each Case line then must be:

• Field/Expression is a boolean test such that if the Field/Expression is/returns empty it is False, and if it has any data it is True
• If an Expression is used, it must be surrounded with ( ) to be evaluated
• The Not operator can be placed in front of a boolean test to reverse the boolean logic. In the case of an Expression, Not must come before the ( ) eg. Case Not ( )

When Condition:

• The list of Condition operators, Text and Math, are generic across other If commands in MOX, and are documented on the Syntax page. Note the separate list of Math vs. Text operators; the Math operators are doubled-up
• When testing a Field/Value against another Field/Value, ( ) must not be used
• Testing a Field/Value against an Expression, the Field/Value must be on the Select line of the Condition and the Expression surrounded by ( ) on the Case line
      ie. Correct:    Select MyField : Case (OtherVal + 123)
      ie. Incorrect: Select (OtherVal + 123) : Case MyField
• An Expression may not be tested against another Expression
      ie. Incorrect: Select (MyField + 123) : Case (OtherVal - 456)

Case Else:

• The optional Case Else statement may be included at the end of a Select / End Select block, and will execute when all previous Case tests are False

Notes:

• As with all Expressions in MOX, an Expression in a test may include one or more MOX Functions. However, user-defined Functions cannot be used in an Expression; they are for assignments only
• Nested Select / End Select blocks are not allowed, but inline If / Then tests are allowed within them, and If / End If blocks may be used inside a Select / End Select block and vice versa. This decision was made early on to prevent "spaghetti code", forcing developers to write more modular code by wrapping these nested levels in Methods, and it has worked well.
• Each Select / Case pairing is the logical equivalent of one ElseIf line in an If / End If block with the comparison defaulting to =. Alternative comparisons, such as using == for a numeric comparison, may be used either on the Select line or on each Case line. If a comparison exists on both the Select line and a Case line, the comparison from the Case line is used.
• The use of And and Or lines for additional criteria are not supported by Case; they are exclusive to If / ElseIf.

Examples:

Method Start(pQ)
    [Pull] (pQ), "Ajax Route Action"
    Select
        Case Ajax : AjaxReply   : Start.Ajax   pQ
        Case Route              : Start.Route  pQ
        Case Action             : Start.Action pQ
        Case Else               : Default.Get  pQ
    End Select
End Method

Method Start.Route(pQ)
    [Pull] (pQ), "Route"
    Select Route
        Case cRouteFirst  : Route.First  pQ
        Case cRouteSecond : Route.Second pQ
        Case Else         : End.NotFound pQ
    End Select
End Method

[New] SixtyFive = 65
Select SixtyFive ==    'Test against a number
    Case 55
        abc = 123
    Case 65
        def = 456
End Select

[New] SixtyFive = 65
Select SixtyFive
    Case > 7
        HtmlAlert    "Does not display because this is the text comparison operator"
    Case >> 7
        HtmlAlert    "This is true because this is the numerical comparison operator"
End Select

If Req.Mode = "Post" : And Req.HasFile
Or Req.Mode = "Get"  : And Not Req.HasFile
    abc = 123
Else
    Select
        Case Not (SessionIsGroupType$ "DB Admin, Office Admin, Office")
            HtmlAlert "When evaluating an expression, surround it with ( )"
            abc = 321
        Case 456 == (abc - def)
            HtmlAlert     "When testing Math, use the doubled-up Math operators"
            zxy = 456
        Case bOther
            def = 654
            If bFinal Then Other.Method.DoSomething
        Case Else
            def = 456
    End Select
End If