Does any other language other than JavaScript have a difference between brace start locations (same line and next line)?

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 

Answer 2

The JavaScript interpreter automatically adds a ; at the end of each line if it doesn't find one (with some exceptions, not getting into them here :).

So basically the issue is not the braces' location (which here represent an object literal, not a code block as in most languages), but this little "feature" that forces your first example to return ; => undefined. You can check out the behavior of return in the ES5 spec.

For other languages that have similar behavior, check out Konrad's answer.