[Caml-list] 2147483648l < 2147483647l
Hello, I am sorry, I have a stupid question. I would like to ask if this: # 2147483648l < 2147483647l;; - : bool = true should not regarded as a bug. In my project I need Int32 value and above behavior surprised me. Value 2147483648l should not be allowed at all because it cannot be encoded to 32-bit signed integer encoded with 2's complement representation. Thanks in advance for help. ___ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
Re: [Caml-list] 2147483648l < 2147483647l
On Tue, Jan 5, 2010 at 13:59, Matej Kosik wrote: > Hello, > > I am sorry, I have a stupid question. > I would like to ask if this: > > # 2147483648l < 2147483647l;; > - : bool = true > > should not regarded as a bug. In my project I need Int32 value and above > behavior surprised me. Value > > 2147483648l > > should not be allowed at all because it cannot be encoded to 32-bit > signed integer encoded with 2's complement representation. > > Thanks in advance for help. yes that's a "misfeature" of the lexer/parser. The point is that it accepts -2147483648l (representable as an int32) ; the downside is that it accepts 2147483648l and treats it as -1l. Cf. this bug report: http://caml.inria.fr/mantis/view.php?id=4210 . -- Olivier ___ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
RE: [Caml-list] 2147483648l < 2147483647l
Matej Kosik wrote: > I am sorry, I have a stupid question. > I would like to ask if this: > > # 2147483648l < 2147483647l;; > - : bool = true The bug is in fact: # 2147483648l;; - : int32 = -2147483648l and given that behaviour, the above result makes sense! But... > it cannot be encoded to 32-bit > signed integer encoded with 2's complement representation. and it's outside the range [Int32.min_int, Int32.max_int] However, it's a known bug - http://caml.inria.fr/mantis/view.php?id=4210 According to Mantis, it's fixed in 3.12 - I'm sure there's a reason that it's not been fixed in 3.11.2+rc1 David ___ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
Re: [Caml-list] 2147483648l < 2147483647l
"David Allsopp" writes: > Matej Kosik wrote: >> I am sorry, I have a stupid question. >> I would like to ask if this: >> >> # 2147483648l < 2147483647l;; >> - : bool = true > > The bug is in fact: > > # 2147483648l;; > - : int32 = -2147483648l > > and given that behaviour, the above result makes sense! But... Isn't that documented properly? I think in the docs I saw at least that ocaml will silently overflow ints. But yeah, the parser/compiler should really warn when that happens. MfG Goswin ___ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
RE: [Caml-list] 2147483648l < 2147483647l
Goswin von Brederlow wrote: > "David Allsopp" writes: > > > Matej Kosik wrote: > >> I am sorry, I have a stupid question. > >> I would like to ask if this: > >> > >># 2147483648l < 2147483647l;; > >>- : bool = true > > > > The bug is in fact: > > > > # 2147483648l;; > > - : int32 = -2147483648l > > > > and given that behaviour, the above result makes sense! But... > > Isn't that documented properly? I think in the docs I saw at least that > ocaml will silently overflow ints. Arithmetic operations are allowed to overflow silently but at no point do you end up with an illegal constant which is the bug here. i.e. Int32.add 2147483647l 1l correctly evaluates to -2147483648l but -2147483648l is a valid int32. The evaluation of a constant by the compiler in your ML source is supposed to follow the same rules as Int32.of_string (which would raise an exception if given "-2147483648l") hence 2147483648l which is not a valid int32 should be a "syntax" error. David ___ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
Re: [Caml-list] 2147483648l < 2147483647l
On Jan 19, 2010, at 1:28 PM, David Allsopp wrote: Goswin von Brederlow wrote: # 2147483648l;; - : int32 = -2147483648l Isn't that documented properly? I think in the docs I saw at least that ocaml will silently overflow ints. Arithmetic operations are allowed to overflow silently but at no point do you end up with an illegal constant which is the bug here. i.e. Int32.add 2147483647l 1l correctly evaluates to -2147483648l but -2147483648l is a valid int32. The evaluation of a constant by the compiler in your ML source is supposed to follow the same rules as Int32.of_string (which would raise an exception if given "-2147483648l") hence 2147483648l which is not a valid int32 should be a "syntax" error. As a point of clarification, the top level and the to_string functions do have the same behavior; none of them raise an exception when given a literal representing max_int+1 or min_int. It doesn't matter whether this is done with ints, Int32s, or Int64s. (I am using OCaml 3.11.1 on a 32-bit machine.) # 1073741824,-1073741824;; - : int * int = (-1073741824, -1073741824) # int_of_string "1073741824",int_of_string "-1073741824";; - : int * int = (-1073741824, -1073741824) # 2147483648l,-2147483648l;; - : int32 * int32 = (-2147483648l, -2147483648l) # Int32.of_string "2147483648",Int32.of_string "-2147483648";; - : int32 * int32 = (-2147483648l, -2147483648l) # 9223372036854775808L,-9223372036854775808L;; - : int64 * int64 = (-9223372036854775808L, -9223372036854775808L) # Int64.of_string "9223372036854775808",Int64.of_string "-9223372036854775808";; - : int64 * int64 = (-9223372036854775808L, -9223372036854775808L) -Elnatan___ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
