Re: if/else syntax

Brackets are mandatory on if statements in Perl.

Note that, unlike C and Pascal, these are defined in terms of BLOCKs, not statements. This means that the curly brackets are required--no dangling statements allowed.

The optionality of the brackets is a source of problems for C.

In Perl 6, it's the parens around the condition that are optional. They're already optional around the condition of statement modifiers in Perl 5.

someFunc() if ($someVar == $anotherVar);
someFunc() if $someVar == $anotherVar;     # Same thing
[download]

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Re^2: if/else syntax by Anonymous Monk on Jun 26, 2009 at 15:48 UTC
so if the brackets are there to avoid problems, the C/perl syntax `(a?b:c)` also has those problems right ?	[reply] [d/l]
Re^3: if/else syntax by ikegami (Patriarch) on Jun 26, 2009 at 16:49 UTC
(a?b:c) also has those problems right ? No, because the "`:`" isn't optional like `else` is, and because people don't indent the conditional operator like they would an if/else. It has a different problem, though. A frequent mistake with the conditional operator is to use it as follows: `$c ? $x = $i : $y = $j;` [download] The above means `( $c ? $x = $i : $y ) = $j;` [download] but people expect it to mean `$c ? ($x = $i) : ($y = $j);` [download]	[reply] [d/l] [select]
Re^4: if/else syntax by Anonymous Monk on Jun 26, 2009 at 17:05 UTC
a thats true. indeed, the fact that ":" isn't optional changes everything, now it makes more sense. thanks.	[reply]
Re^3: if/else syntax by Crackers2 (Parson) on Jun 26, 2009 at 16:10 UTC
I don't think so. With if/else: `if a if b c else d` [download] could mean `if a { if b { c } else { d } } or if a { if b { c } } else { d }` [download] With the ternary operator that would be `a ? b ? c : d : () and a ? b ? c : () : d` [download] so there's no abmbiguity.	[reply] [d/l] [select]
Re^4: if/else syntax by gwadej (Chaplain) on Jun 26, 2009 at 16:44 UTC
There's actually no ambiguity in the C syntax for your example. The compiler understands it fine. The problem is that the programmer/reader of the code does not always read it the same way. `if(a) if(b) c(); else d();` [download] According to what I recall, the `else` matches with the nearest `if` in this case. Unfortunately, indentation gives humans fits on this. `if(a) if(b) c(); else d();` [download] This does the same thing (`else` goes with `if(b)`). As I said, there's nothing ambiguous about it. G. Wade	[reply] [d/l] [select]
Re^5: if/else syntax by Anonymous Monk on Jun 26, 2009 at 17:01 UTC
Re^5: if/else syntax by ikegami (Patriarch) on Jun 26, 2009 at 17:20 UTC
Re^6: if/else syntax by massa (Hermit) on Jun 26, 2009 at 17:33 UTC
Re^6: if/else syntax by gwadej (Chaplain) on Jun 29, 2009 at 13:34 UTC
Re^4: if/else syntax by Anonymous Monk on Jun 26, 2009 at 16:27 UTC
so why we can't have a if/else syntax without brackets that behaves just like the ternary operator ? `if a { if b { c } else { d } } or if a { if b { c } } else { d }` [download] Does not matter who the compiler will assume, since if it get implemented we would know it before hand	[reply] [d/l]
Re^5: if/else syntax by Transient (Hermit) on Jun 26, 2009 at 17:21 UTC
Re^3: if/else syntax by dreadpiratepeter (Priest) on Jun 26, 2009 at 15:51 UTC
what you are looking for is: `if ($cond==1) { do_good(); } else { do_bad(); }` [download] -pete "Worry is like a rocking chair. It gives you something to do, but it doesn't get you anywhere."	[reply] [d/l]


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