How do different languages handle the "dangling else"?

Question

I often see the dangling else handled as:

if (x > 0)
  if (y > 0)
    print "hello"
else
  print "world"

the parser or interpreter will actually match the else with the closest if statement, which is the "if (y > 0)".

Does any language have the pitfall of actually matching the else with the outer if or the farthest if? (except the obvious Python)

Answer 1

Short of using space-sensitive languages (like Python, as you said), I don't see why any sensible interpretation would match the outermost if block.

Some languages prohibit this potential ambiguity by:

1. Requiring braces for all blocks, and
2. Providing special "else if" syntax, usually elsif, elif, or elseif.

Answer 2

If any language did that (except for the indentation-centric languages), they would have to go into one of the "what is the worst language" lists.

This is also why I almost always use braces for conditionals, and 100% of the time when there are nested conditionals or loops. The few extra characters is worth eliminating the possibility of confusion.

Answer 3

In Perl, braces are not optional which helps us avoid such issues:

if ($x > 0) {
    if ($y > 0) {
        print "hello"
    }
    else {
        print "world"
    }
}

versus

if ($x > 0) {
    if ($y > 0) {
        print "hello"
    }
}
else {
    print "world"
}

IIRC, most C style guidelines require/recommend braces for loops and conditionals.