Question

Today, while I was randomly reading the JavaScript patterns O’Reilly book, I found one interesting thing (page 27 for reference).

In Javascript, in some cases, there is a difference if the brace start location is different.

function test_function1() {
    return
    {
        name: 'rajat'
    };
}

var obj = test_function1();
alert(obj);  //Shows "undefined"

While

function test_function2() {
    return {
        name: 'rajat'
    };
}

var obj = test_function2();
alert(obj); //Shows object

JSfiddle Demo

Does any other language out there have such behavior? If so, then I would have to change my habit for sure..:)

I am mainly concerned about PHP, C, C++, Java, and ruby.

Answer 1

Any language that doesn’t rely on semicolons (but instead on newlines) to delimit statements potentially allows this. Consider Python:

>>> def foo():
...   return
...   { 1: 2 }
... 
>>> def bar():
...   return { 1: 2 }
... 
>>> foo()
>>> bar()
{1: 2}

You might be able to construct a similar case in Visual Basic but off the top of my head I can’t figure out how because VB is pretty restrictive in where values may be placed. But the following should work, unless the static analyser complains about unreachable code:

Try
    Throw New Exception()
Catch ex As Exception
    Throw ex.GetBaseException()
End Try

' versus

Try
    Throw New Exception()
Catch ex As Exception
    Throw
    ex.GetBaseException()
End Try

From the languages you mentioned, Ruby has the same property. PHP, C, C++ and Java do not simply because they discard newline as whitespace, and require semicolons to delimit statements.

Here’s the equivalent code from the Python example in Ruby:

>> def foo
>>   return { 1 => 2 }
>> end
=> nil
>> def bar
>>   return
>>   { 1 => 2 }
>> end
=> nil
>> foo
=> {1=>2}
>> bar
=> nil