15 Jan, 2013, Runter wrote in the 1st comment:
Votes: 0
Does anyone know of a programming language that does this:

2d_map = {some_key: {second_key: "hello world"} }

if (2d_map["some_key"]["second_key"])
print it

In this example, it is a keyword that represents the value of the if statement. Anyone know a language do this without requiring setting a variable yourself?
15 Jan, 2013, Davion wrote in the 2nd comment:
Votes: 0
New to me.
15 Jan, 2013, Twisol wrote in the 3rd comment:
Votes: 0
Eh. An implicit binding is usually a bad sign, IMO. I like this version in Haskell, though.

ifMaybe :: Maybe a -> (a -> IO ()) -> IO ()
ifMaybe = flip $maybe (return ()) 2d_map = [('some_key', [('second_key', "hello world")])] main = do let item = (lookup "second_key" <=< lookup "some_key")$ 2d_map
ifMaybe item $\it -> do print it – could shorten lines 6 and 7 to this, since it is such a short block: – ifMaybe item print Plus, you can chain arbitrarily deep into your object without getting an exception. If a Nothing is returned at any point, the whole lookup just resolves to Nothing. 15 Jan, 2013, Rarva.Riendf wrote in the 4th comment: Votes: 0 Looks like 2 imbricated Java Hashmap to me. Or do I miss something. No idea if this could compile though public HashMap<String, HashMap <String, String>> myMap = new HashMap() { put("firstkey", new HashMap() { put("secondKey", "test"}}; 15 Jan, 2013, Davion wrote in the 5th comment: Votes: 0 Rarva.Riendf said: Looks like 2 imbricated Java Hashmap to me. Or do I miss something. Implicit declaration of the 'it' keyword based on the evaluation of the if statement. 15 Jan, 2013, Twisol wrote in the 6th comment: Votes: 0 You just taught me a new word! But I think he was asking about having a variable automatically and implicitly bound to the result of the 'if' condition. 15 Jan, 2013, Rarva.Riendf wrote in the 7th comment: Votes: 0 Davion said: Implicit declaration of the 'it' keyword based on the evaluation of the if statement. I knew I missed something somehow… 15 Jan, 2013, Tyche wrote in the 8th comment: Votes: 0 Runter said: In this example, it is a keyword that represents the value of the if statement. Anyone know a language do this without requiring setting a variable yourself? I don't see why a language couldn't. I don't know of any, but depending on block scoping rules of a particular language, it might be highly undesirable in some. 15 Jan, 2013, Runter wrote in the 9th comment: Votes: 0 Okay, I'll admit it. I'm being super lazy. I think I was confusing in my original post so this is what I mean: if exp print it being the same as: var = exp if exp print var Yes, very lazy. I just see the pattern come up a lot so I was curious if any language did something like this. I couldn't think of any. 15 Jan, 2013, Rarva.Riendf wrote in the 10th comment: Votes: 0 Well if you are that lazy, factorize! void ifprint(void toto) { if (toto) print toto } ifprint(toto) in the long run, there is even fewer character than "if toto print toto" 15 Jan, 2013, Kaz wrote in the 11th comment: Votes: 0 I don't know of a language that does this. The problem I see is that it breaks down far too easily with anything but the most trivial logic. Consider: if (a = b and c = d) print it What gets printed? 15 Jan, 2013, Runter wrote in the 12th comment: Votes: 0 Kaz said: I don't know of a language that does this. The problem I see is that it breaks down far too easily with anything but the most trivial logic. Consider: if (a = b and c = d) print it What gets printed? It depends on the language in question, but whatever the expression evaluates to. In some languages that will evaluate to true/false. In all languages I'm aware of if statements evaluate to a single value. 15 Jan, 2013, Idealiad wrote in the 13th comment: Votes: 0 I guess it depends if you actually want to keep the var around. In a language with s-expressions for example this is the only way it works. > (println (if 1 "foo")) foo nil > Clojure has an if-let: > (if-let [it 1] (println it)) 1 nil > But if-let is just a macro, so pretty much what RR was talking about. 17 Jan, 2013, Scandum wrote in the 14th comment: Votes: 0 TinTin++ supports this behavior for regular expression if checks. One problem in the given example is how to handle: if (bla) if (bli) print it A language could support %if, %%if for the 2nd nest, etc. It'd be pure bloat imo. 17 Jan, 2013, Runter wrote in the 15th comment: Votes: 0 Scandum said: TinTin++ supports this behavior for regular expression if checks. One problem in the given example is how to handle: if (bla) if (bli) print it I would expect in this case to print the value of bli. 19 Jan, 2013, Telgar wrote in the 16th comment: Votes: 0 Doesn't perl do this? if (bla) print$_;
Random Picks

0.0/16