Ternary operator clarification ($1 = 0) ? ($b = 0) : ($b = 1)

[kylomas]

Hi,

I am trying to use the ternary operator as follows:

local $b

for $1 = 0 to 1
    ;($1 = 0) ? ($b = 0) : ($b = 1)     ; this does NOT work, should it???
    $b = ($1 = 0) ? (0) : (1)           ; this works
    ConsoleWrite($b & @LF)
Next

Should the commented use of the ternary operator work?

Thanks,

kylomas

[Melba23]

kylomas,

I do not think so as the True/False arguments are not assignments - they are just evaluated and returned from the function. If you actually look at the return you get it is pretty obvious what is happening:

$b = 1

For $1 = 0 To 1
    $c = ($1 = 0) ? ($b = 0) : ($b = 1) ; Should be False if $1 = 0 and True if not
    ConsoleWrite($c & @CRLF)
Next

Does that help?

M23

[guinness]

Not it shouldn't work. $b = 0 doesn't assign 0 to $b.

[jchd]

No. The scheme is:

condition ? expressionTrue : expressionFalse

and the whole evaluates to whatever expression gets selected.

Hence the construct can be used as a right-hand value.

Your first statement matches a different scheme:

condition ? statementTrue : statementFalse

[kylomas]

M23, guinness,

Thanks...

@jchd, you're right.  I was misinterpreting "statement" and "expression". 

kylomas

[czardas]

It's funny to me that the name 'ternary operator' is still in use. There are only two possible outcomes, and not three (as the name would imply). Perhaps I'll create my own ternary operator with three outcomes. It makes sense to me.

Got it!

>> pseudo code expression <<

("string" > 1) = Undefined ; should return True because "string" is the wrong data type for this particular comparison.

I would be surprised if this doesn't already exist somewhere.

Edited January 6, 2014 by czardas

[Richard Robertson]

czardas, every operator only has a single result. Unary operators take a single argument (not $var). Binary operators take two arguments ($a + $. Ternary operators take three arguments (if ? true : false).

Edit: damn emotes

Edited January 6, 2014 by Richard Robertson

[czardas]

czardas, every operator only has a single result.

 

That might be true of today's computers, but I don't believe it has always been that way nor does it need to be. It's quite limiting and to be honest I also think it's hard to justify. Take square roots as an example - which yeild two results.

Sorry my responce was a bit rushed before between important tasks.

Edited January 6, 2014 by czardas

[czardas]

It's the type of result I'm refering to here. True and False (binary logic) just don't cut it on their own. The ternary operator, as the term is generally used, has a single input (expression) and two possible outputs. It's unary (input) and binary logic (output).That's actually only two arguments. Adding 1x input and 2x output together and calling it ternary is stretching the imagination beyond all reason. That's (I believe) why it also has a more sensible name - something like conditional operator. It's all in wikipedia.

Admittedly I added my own slant on the subject (slightly) - trying to make sense of it all.

Edited January 6, 2014 by czardas

[BrewManNH]

The term refers to the number of arguments it takes, not what the results of the arguments are. Ternary takes 3 arguments conditional expression/value_if_true/value_if_false. Binary expressions take 2 arguments $a = b or $a + b etc. Unary take one argument and refer to booleans if I'm not mistaken.

[czardas]

There are only two arguments: the expression is true = 1st argument. - the expression is false = 2nd argument. Where is there a third argument? I don't see it.

Edited January 6, 2014 by czardas

[BrewManNH]

The conditional expression is the third

[guinness]

I see three as well. CONDITIONAL ? RETURN TRUE : RETURN FALSE

[Mat]

Binary logic is nothing to do with binary operations.

And the ternary operator takes 3 inputs and gives 1 output. What gives you the idea it has 2 outputs?

Edit: Arity if you want some reading.

Edited January 6, 2014 by Mat

[czardas]

Hmm semantics in programming sucks. There are definately two arguments from a linguistic / logical POV.

Edited January 6, 2014 by czardas

[guinness]

I would say one argument two outputs.

[czardas]

I would say one expression, two arguments.

Since there are clearly two logical arguments and also three arguments - I see a semantic conflict here.

Edited January 6, 2014 by czardas

[BrewManNH]

I believe you're confusing ternary LOGIC with a ternary operator, ternary logic has 3 possible outcomes, and a ternary operator needs 3 parameters.

[czardas]

I believe you're confusing ternary LOGIC with a ternary operator, ternary logic has 3 possible outcomes, and a ternary operator needs 3 parameters.

 

If people insist on this naming strategy, then confusion is to be expected.

Edited January 6, 2014 by czardas

[Mat]

The ternary (or conditional) operation is an expression with 3 parameters. The user passes the operator 3 expressions as arguments and receives a return value.

It's exactly the same from a liguistics point of view as if we were still using _Iif() (a function with 3 parameters, that takes 3 expressions as arguments and returns a value). The only difference is that one of the expressions is not evaluated by the ?: operator. That's not relevant though.