Ternary operator in multiple lines

[juliohm]

The parser fails with the ternary operator in two lines:

foo = 1 > 0 ? 1
            : 0

ERROR: syntax: colon expected in "?" expression

[sjkelly]

You just need to put the colon on the same line as the question mark:

julia> foo = 1 > 0 ? 1 :
       0
1

[jiahao]

Alternatively, you can use parentheses:

julia> foo = (1 > 0 ? 1
      : 0)
1

[juliohm]

I mean, this is intended behavior? We really need the parenthesis there?

[IainNZ]

Maybe you could argue that the the parser, having seen a ?, but not a :, should keep looking until it finds one I suppose. I think the current behavior is the C behaviour (but my memory might be shakey)

[juliohm]

@IainNZ C allows the break before the semicolon:

int main()
{
    int foo = 1 > 0 ? 1
                    : 0;
}

[jiahao]

I think the current behavior is simply what the parser currently gives us.

Related: #6823 #9180

[StefanKarpinski]

There's also been some discussion of allowing just the ? without the : to mean something (forget the issue), although I didn't really care for it myself.

[quinnj]

Yeah, I was a bigger fan of allowing single line if-then statements, so you
could do

if x then y

instead of

if x; y; end

On Sun, Feb 22, 2015 at 9:34 PM, Stefan Karpinski notifications@github.com
wrote:

There's also been some discussion of allowing just the ? without the : to
mean something (forget the issue), although I didn't really care for it
myself.

—
Reply to this email directly or view it on GitHub
#10291 (comment).

[JeffBezanson]

Yes, that is #6823. Even if we don't adopt the x ? y syntax, it's good that we erred on the side of leaving it open instead of allowing every combination of whitespace. I don't see the value of putting the : on the next line.