if() function

Could someone explain why the following code work without compiler errors?

if(
    isnull(ri!user),
    "",
    isusernametaken(ri!user),
    user(ri!user, "firstName") & " " & user(ri!user, "lastName"),
    joinarray(split(ri!user, "."), " ")
)

I expect some kind of evaluation error, but it works just as the three lines starting on "isusernametaken" were an embedded if.

I saw that in one of the Appian courses and I'm wondering if it is some undocumented feature of the if function.

Thank you

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  • +1
    Certified Lead Developer

    if() has hidden else if functionality in it.  What's documented is:

    if(

    condition

    return if true,

    return if false

    )

    What you can do with it:

    if(

    condition1,

    return if condition1 true

    condition2 if condition1 false {else if}

    return if condition2 true

    return if condition2 false

    )

    Or you can do it with 7, 9, 11, 13.  Every odd input is another conditional until the very last one, what returns if they're ALL false.

    It's way less keypresses, but gets dramatically unreadable.

  • Another interesting thing about using if(a, b, c, d, e, [..., ...]) format is that it'll break Appian in places that absolutely require "Design Mode" functionality - for instance, if you try to use it (pretty much anywhere) in the Record Grid Designer.  If you use it in a regular interface, it'll cause Appian to refuse to switch back to Design Mode from Expression Mode (though some might see this as more of a "pro" than "con", lol).

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  • Another interesting thing about using if(a, b, c, d, e, [..., ...]) format is that it'll break Appian in places that absolutely require "Design Mode" functionality - for instance, if you try to use it (pretty much anywhere) in the Record Grid Designer.  If you use it in a regular interface, it'll cause Appian to refuse to switch back to Design Mode from Expression Mode (though some might see this as more of a "pro" than "con", lol).

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