11 replies to this topic

[lordkrandel]

What about making third part of the ternary operator optional with a null default ("") ?

v .= (condition ? "a" )
Add "a" only if condition, do nothing otherwise.

[HotKeyIt]

Already possible:

MsgBox % v .= true [color=red]?[/color] "a" [color=red]:[/color]

[Lexikos]

It may appear to work in some cases, but only because AutoHotkey handles stack underflow gracefully (i.e. it silently aborts the expression). It does not, in fact, work in this case.

v := "This is not displayed"
MsgBox % v .= false ? "a" :

It is impossible to use only two operands with the ternary operator, by definition. (x ? y) would be a binary operation.

[HotKeyIt]

Thanks Lexikos for pointing out, again something learned

[lordkrandel]

I'm using this at the moment

my_if(k,v) {
    return (k ? v : "")
}

modifiers := ""
     . my_if(vCtrl, "Ctrl")
     . my_if(vAlt, "Alt")
     . my_if(vShift, "Shift")
     . my_if(vWin, "Win")
hotkey := my_if(modifiers, modifiers "+") hotkey

[RaptorX]

you can safely say:

    return (k ? v [color=red]:[/color])

if you dont like adding "".

I personally have a variable called null that i always set to "".
that way I say:

    return (k ? v : null)

Which is kind of more appealing.

I personally would like if the variable null was like the variables true and false. That is that its content cant be changed. That way i could use that expression in any script without having to make sure that it is really empty.

[jaco0646]

RaptorX, please read the thread. Your initial code is not safe. I like the idea of a null constant for readability, though.

[RaptorX]

No, I gave a correct answer.

His return code simply checks if the variable k is empty, and returns v or nothing which i am positive my initial code does without problems.

Keep in mind that the code i recommended is in the context of his "my_if" function which is his creative solution to this algorithm:

_mhk:=(_ctrl ? "^" : null)(_alt ? "!" : null)(_shift ? "+" : null)(_win ? "#" : null)(_hkddl = "None" ? "#``" : _hkddl) ; main hotkey

I use the above code for saving a hotkey from a GUI.
Note that if you dont use null or "" or simply : the above does not work. You cannot simply say: (_ctrl ? "^")

I could easily say using his method:

_mhk:= check(_ctrl, "Ctrl") check(_alt, "Alt") check(_shift, "Shift") check(win, "Win") (_hkddl = "None" ? "#``" : _hkddl)
check(mod, set){
    return mod ? set :             ; I dont use parentheses unless strictly necessary like above.
}

Which would work as you expect it to work.
But as Lexikos did point out, that is not always the case. There are some special cases, like the one he showed:

v := "This is not displayed"
MsgBox % v [color=red].=[/color] false ? "a" :     ; this wouldnt append... it behaves as if you used ":=" instead

Curiously if you use true in the above code it does append normally.

[Lexikos]

If the false branch is missing and the condition evaluates to false, one of two things happen:
[*:3909f2yg]If the stack is empty, the expression is aborted and it yields an empty string.
[*:3909f2yg]Otherwise, the wrong value is popped off the stack; probably one meant for the next operation. The next operation will thus also pop the wrong value off the stack, and so on until the stack is emptied prematurely and the expression is aborted.Since an aborted expression evaluates to "", in some cases it will appear correct. Although it may work, it is not supported, and therefore should not be used.

[jaco0646]

Same here?

v := "This is not displayed"
MsgBox % v .= true ?  : "a"

[Lexikos]

Yes. There are also other syntax errors which cause stack underflow, such as 2-/1.

[lordkrandel]

That could also be a ||= b, as in other languages