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Dangling Else

Name: Anonymous 2013-06-16 13:34

Why allowing IFs missing ELSE at all? Even Scheme forbids IFs without ELSE clause. Although retarded Common Lisp allows them, despite having WHEN and UNLESS.

Name: Anonymous 2013-06-16 13:50

You from a time machine? Haskell has already made all lisps obsolete.

Name: Anonymous 2013-06-16 14:03

>>2
Haskell is a piece of shit:
http://en.wikibooks.org/wiki/Haskell/Indentation

Name: Anonymous 2013-06-16 14:08

Scheme forbids IFs without ELSE clause
Nigger, have you read your SICP?

syntax:  (if <test> <consequent> <alternate>)
syntax:  (if <test> <consequent>)
Syntax: <Test>, <consequent>, and <alternate> may be arbitrary expressions.
Semantics: An if expression is evaluated as follows: first, <test> is evaluated. If it yields a true value (see section 6.3.1), then <consequent> is evaluated and its value(s) is(are) returned. Otherwise <alternate> is evaluated and its value(s) is(are) returned. If <test> yields a false value and no <alternate> is specified, then the result of the expression is unspecified.
http://schemers.org/Documents/Standards/R5RS/HTML/r5rs-Z-H-7.html#%_sec_4.1.5

Name: Anonymous 2013-06-16 14:11

>>4
Suck a Yahweh, kike.
Welcome to DrRacket, version 5.2.1 [3m].
Language: racket; memory limit: 128 MB.
(if 1 2)
. if: bad syntax (must have an "else" expression) in: (if 1 2)

Name: Anonymous 2013-06-16 14:14

>>5
U MENA
Welcome to DrRacket, version 5.3.4 [3m].
Language: r5rs; memory limit: 128 MB.
(if 1 2)
2

Name: Anonymous 2013-06-16 14:14

>>3
WAAAH I CANNOT INTO INDENTATION HUCHKELL SUX =(((

Name: Anonymous 2013-06-16 14:17

>>6
Language: r5rs
found your problem.

r5rs is long obsolete.

Name: Anonymous 2013-06-16 14:19

>>8
Rationale

The one-armed variant of if was removed from Racket to prevent bugs.

In functional code one always uses the two-armed variant of if.

(if test expr-on-true expr-on-false)

Forgetting the second arm expr-on-false would not lead to a syntax-error, but to a runtime error (the expression would return #<void>).

To prevent these often occurring bugs in functional code, it was decided to introduce the form when for the one-armed variant of if.

 (when test expr-on-true)

Besides preventing accidental bugs, the new form clearly indicated to a reader of code, that the code relies on side effects.

Name: Anonymous 2013-06-16 14:34

>>5
Racket is not Scheme.

Name: Anonymous 2013-06-16 14:58

>>10
America is not a Country.

Name: Anonymous 2013-06-16 15:12

>>8

It's a good thing no one ever writes anything important in scheme. All work is displaced by language incompatibility every 2-4 years.

Name: Anonymous 2013-06-16 15:17

>>12
Actually, Lisp became much more stable over the last 50 years.

No new features added, while redundant features being removed.

Name: Anonymous 2013-06-16 15:21

>>13

Fiddling with the syntax with no additional benefit doesn't do anything other than making it harder to use existing code.

Name: Anonymous 2013-06-16 15:23

>>14

see >>9

Moreover, tethinking IF does have benefit of making language more orthogonal and simplifying implementation.

Name: Anonymous 2013-06-16 15:38

>>15
Not enough benefit to out date a project. See the computer algebra system written in r5rs. I would much rather have that than some language lawyers constantly threatening to depreciate all of my work on a whim.

Name: Anonymous 2013-06-16 16:08

>>12
Sure, that's true if you're a fucking idiot.

Name: Anonymous 2013-06-16 16:15

>>13
But lithp doesn't have any features to speak of. Not even syntax. Everything is at a "could be done" state.

Name: Anonymous 2013-06-16 16:33

This is really just syntax jabbering.  If you really don't like else-less if statements, just add empty else clauses where you see fit.  If you're worried about proving code correctness or something, just add implicit empty else clauses.

Why is language syntax such a popular subject for divas anyway?  If I had my way, anybody who brought this sort of bullshit up in a forum other than a discussion of compiler/interpreter implementation would be forced to write a SLOC counter for perl in perl, then use it exclusively until they'd written 250k SLOC.  And if they brought me a hickory branch that was too thi-- I mean, if they wrote their counter too leniently, I'd make them golf their programs first!

Name: Anonymous 2013-06-16 16:34

>>18
Absence of features is a feature in itself.


And then comes the Walter Bright retard with his retarded solution:
http://www.drdobbs.com/cpp/dangling-else-yet-again/231602010

Instead of dropping one-armed IFs, Bright retard invents retarded scheme of rules, complicating his already retarded D language.

Name: Anonymous 2013-06-16 16:38

>>20
http://www.drdobbs.com/cpp/dangling-else-yet-again/231602010
Andrei Alexandrescu
JEW.

Name: Anonymous 2013-06-16 17:09

DANGLE MY ANUS

Name: Anonymous 2013-06-16 20:03

>>20
How is "ambiguity is illegal" a retarded scheme of rules?

Name: Anonymous 2013-06-16 20:15

Test

Name: Anonymous 2013-06-16 21:48

>>23
 It works by keeping track of any lexically enclosing statement that is looking for an else clause, so if an else clause is found for the current statement without a following { }, then it is marked as illegal.

As far as I know, no other language has implemented this solution, though GCC does check for a subset. I think it's great that there is still room for better solutions to ancient programming problems.

Name: Anonymous 2013-06-16 22:04

>>1
That or we could do away with that old archaic else statement! ^^

Name: Anonymous 2013-06-16 22:07

...programmers should be Expert enough to work around this ^^

Name: Anonymous 2013-06-16 22:09

xD to the functional programmers horror

Name: Anonymous 2013-06-16 22:17

>>25
Yes, I read it. The implementation is not the rule, and anyway I don't see why that's so bad - it's the first thing I thought of.

That's like saying the rules of a sport suck because you don't like the way the referee talks.

Name: Anonymous 2013-06-16 22:20


boolean boolelse;
loop(1){
  boolelse = true;
  if(something){
    boolelse = false;
    ...
    }
  if(boolelse){
    ...
    }
  }

Name: Anonymous 2013-06-16 22:41


boolean boolelse;
loop(1){
  boolelse = true;
  if(something){
    boolelse = false;
    ...
    if(somethingelse){
      boolelse = true;
      ..
      if(exceptwhen){
        boolelse = false;
        ..
        if(andthenif){
          boolelse = true;
          }
        }
      }
    }
  if(boolelse){
    ...
    }
  }

Name: Anonymous 2013-06-16 22:53


if(not boolelse){
  ...
  }

Name: Anonymous 2013-06-16 22:55

....but muh else stateemeent!

Name: Anonymous 2013-06-16 23:07

>>33
LLLLLLLLLEEEEEEEEELLLLLLLL E/G/IN MUH MEME /G/ROSKI XDDDDDDDDDDD
>MUH
>MUH
FUCKING E/G/IN LLLLLLLLLLLLLLLLLLEEEEEEEEEEELLLLLLLLLLLLL XDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD LELELELELELELLELELELEL MUH LE SIDES ARE LE FLYING TO LE IMAGEREDDITS XDDDDDDDDDDDDDDD

Name: Anonymous 2013-06-16 23:09

Scheme is functional flavored, but it never was a medium sized dog.

Name: Anonymous 2013-06-16 23:20

>>23
Why would you make a language with ambiguity in the first place.

Name: Anonymous 2013-06-17 1:08

>>36
It's not actually ambiguous, or else it couldn't be parsed.  Check-mate!

Name: Anonymous 2013-06-17 1:44

>>37
chk m8

Name: Anonymous 2013-06-17 1:48

>>38
yo skrill drop it hard

Name: Anonymous 2013-06-17 2:20

>>1
Have a look at Nemerle language. Basically it has two macros: "if" and "when" that unfold themselves into pattern matching.

If you try use if without else clause, you'll be in world of pain.

Name: Anonymous 2013-06-17 8:38

>>29
I don't see why that's so bad
It is Worse is Better.

Name: Anonymous 2013-06-17 8:47

>>40
You can't implement pattern matching without an if.

Name: Anonymous 2013-06-17 8:58

>>42
You could use a computed jump table.

Name: Anonymous 2013-06-17 8:59

>>42
You could use a computed jump table.

Name: Anonymous 2013-06-17 9:00

>>43,44
You could double-post on history change, because shiichan a shit!

Name: Anonymous 2013-06-17 18:04

>>41
I wasn't familiar with what that meant so I skimmed this http://www.jwz.org/doc/worse-is-better.html, and I disagree. The rule allows for a simple, consistent "interface" at the expense of complexity (not even that complex) in the implementation.

I say it's simple and consistent because "ambiguity is illegal" should be a universal rule of a language where there might be ambiguity (whether a language should allow this in the first place is a different question), which means there is no need to add a specific, arbitrary rule for the dangling else problem.

Name: Anonymous 2013-06-17 19:14

>>47
The rule allows for a simple, consistent "interface" at the expense of complexity (not even that complex) in the implementation.
"simple, consistent" interface would be the dropping of one-armed IFs for good.

see >>9

Name: Anonymous 2013-06-17 19:15

dangling dick

Name: Anonymous 2013-06-17 19:16

>>47
Rich Hickey is a Jew, but he explains well why concept convolution is bad:
http://www.infoq.com/presentations/Simple-Made-Easy

Name: Anonymous 2013-06-17 19:55

DICK HICKEY

Name: Anonymous 2013-06-17 20:35

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Name: Anonymous 2013-06-17 20:41

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