CODEWITHSUNDEEP
functionsyntaxreturnternary-operatorautoit
Thm Lee
Thm Lee

Reputation: 1236

Meaning of ":" and "?"

I found semicolons & question marks in a Return statement of an AutoIt script:

#AutoIt3Wrapper_Au3Check_Parameters=-d -w 1 -w 2 -w 3 -w 4 -w 5 -w 6

Func A()
  ;do somethingA
EndFunc

Func B($a,$b,$c)
  ;do somethingB
EndFunc

Func C($a,$b,$c,$d)
  ;do somethingC
EndFunc

Func CallFunc( $f, $a = Default, $b = Default, $c = Default, $c = Default )
  Return FuncName($f) = "A" ? $f() : FuncName($f) = "B" ? $f($a,$b,$c) : $f($a,$b,$c,$d)
EndFunc

Example()

Func Example()
  CallFunc( A )
  CallFunc( B, 1, 2, 3 )
  CallFunc( C, 1, 2, 3, 4 )
EndFunc

I know FuncName() returns the name of a function stored in a variable, but I don't know what question-marks & semicolons mean in this Return statement:

Return FuncName($f) = "A" ? $f() : FuncName($f) = "B" ? $f($a,$b,$c) : $f($a,$b,$c,$d)

Upvotes: 1

Views: 114

Answers (1)

user4157124
user4157124

Reputation: 2904

I don't know question-marks & semicolons meanings

As per Documentation - Keywords - Ternary operator:

Conditionally chooses one of two responses based on the result of an expression.

For example;

Return $g_bBlockInput ? $MOE_BLOCKDEFPROC : $MOE_RUNDEFPROC

is functionally equivalent to:

If $g_bBlockInput Then

    Return $MOE_BLOCKDEFPROC

Else

    Return $MOE_RUNDEFPROC

EndIf

So

Return FuncName($f) = "A" ? $f() : FuncName($f) = "B" ? $f($a,$b,$c) : $f($a,$b,$c,$d)

equals:

If FuncName($f) = "A" Then

    Return $f()

Else

    If FuncName($f) = "B" Then

        Return $f($a,$b,$c)

    Else

        Return $f($a,$b,$c,$d)

    EndIf

EndIf

Whatever that code's purpose seems a case for Switch...Case...EndSwitch instead. Popular use of ternary operator includes conditional assignment. Example:

Global Const $g_bState = True
Global Const $g_sState = $g_bState ? 'ON' : 'OFF'

ConsoleWrite('$g_bState = ' & $g_sState & @CRLF)

Upvotes: 2

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