* Int64 overflow checks
@ 2007-04-30 17:24 Raj B
2007-05-01 2:41 ` [Caml-list] " skaller
2007-05-01 2:45 ` Jon Harrop
0 siblings, 2 replies; 3+ messages in thread
From: Raj B @ 2007-04-30 17:24 UTC (permalink / raw)
To: caml-list
Hi
I am writing an implementation of the Python programming language in
OCaml and ran into an interesting issue.
Python allows the programmer to implicitly perform arbitrary-sized
integer operations by switching internally between its 'int' and
'long' types. (which seems to translate to OCaml's int64 and BigInt).
I found an OCaml library on a mailing list which checks for overflow
in 'normal' 32-bit integer operations. How can I check for overflows
in int64 operations so I can switch to big-int if that happens?
Thanks!
Raj
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Caml-list] Int64 overflow checks
2007-04-30 17:24 Int64 overflow checks Raj B
@ 2007-05-01 2:41 ` skaller
2007-05-01 2:45 ` Jon Harrop
1 sibling, 0 replies; 3+ messages in thread
From: skaller @ 2007-05-01 2:41 UTC (permalink / raw)
To: Raj B; +Cc: caml-list
On Mon, 2007-04-30 at 12:24 -0500, Raj B wrote:
> Hi
>
> I am writing an implementation of the Python programming language in
> OCaml and ran into an interesting issue.
>
> Python allows the programmer to implicitly perform arbitrary-sized
> integer operations by switching internally between its 'int' and
> 'long' types. (which seems to translate to OCaml's int64 and BigInt).
>
> I found an OCaml library on a mailing list which checks for overflow
> in 'normal' 32-bit integer operations. How can I check for overflows
> in int64 operations so I can switch to big-int if that happens?
you use basic maths. For example on addition, you expect
a + b > a
a + b > b
and one of these will be false if you got overflow
(something like that).
--
John Skaller <skaller at users dot sf dot net>
Felix, successor to C++: http://felix.sf.net
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Caml-list] Int64 overflow checks
2007-04-30 17:24 Int64 overflow checks Raj B
2007-05-01 2:41 ` [Caml-list] " skaller
@ 2007-05-01 2:45 ` Jon Harrop
1 sibling, 0 replies; 3+ messages in thread
From: Jon Harrop @ 2007-05-01 2:45 UTC (permalink / raw)
To: caml-list
On Monday 30 April 2007 18:24, Raj B wrote:
> Hi
>
> I am writing an implementation of the Python programming language in
> OCaml and ran into an interesting issue.
>
> Python allows the programmer to implicitly perform arbitrary-sized
> integer operations by switching internally between its 'int' and
> 'long' types. (which seems to translate to OCaml's int64 and BigInt).
>
> I found an OCaml library on a mailing list which checks for overflow
> in 'normal' 32-bit integer operations. How can I check for overflows
> in int64 operations so I can switch to big-int if that happens?
Sounds like a premature optimization. Just use Big_int for everything to start
with...
--
Dr Jon D Harrop, Flying Frog Consultancy Ltd.
The F#.NET Journal
http://www.ffconsultancy.com/products/fsharp_journal/?e
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