March 05, 2009 Re: Null references (oh no, not again!) | ||||
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Walter Bright Wrote: When I see code like this I see bugs. > > Foo f; > if (x < 1) f = new Foo(1); > else if (x >= 1) f = new Foo(2); > f.member(); > This should not compile IMHO default non nullable is necessary. If using a language with default nullable, I would write this as Foo generateFoo() { if (x < 1) return new Foo(1); else if (x >= 1) return new Foo(2); } This way the compiler has to check that there is a returned value for each path. As the conditions become more complex, the compiler enforcing a return value prevents the result from being null (unless of course you return 0 just to prove a point) > Foo f; > bar(&f); > > ? Or in another form: > > bar(ref Foo f); > Foo f; > bar(f); > > Java doesn't have ref parameters. Same problem. The prototype of bar should be Foo bar() if the intent of bar is to return a reference to an instance of Foo. Returning what is conceptually the result of a function in by ref parameters is really nasty way to code IMHO. Alex |
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