[Caml-list] xor on booleans

[Caml-list] xor on booleans

[Christoph Bauer]

Hi,

a little suggestion for the Pervasives module: the
xor operator on booleans

let (^^) = (<>)

Christoph Bauer

-- 
proc self {} {foreach c [split [info body self] ""] d {14 -7 0 0 4 -67 4 73 11
69 24 -83 -15 6 -4 -84 78 20 11 -78 -1 -1 79 19 -8 4} { binary scan $c c c
if {[catch {append r [format %c [expr $c+$d]]}]} {return $r};}};puts [self]
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Re: [Caml-list] xor on booleans

[Frederic De Jaeger]

CB> Hi,
CB> a little suggestion for the Pervasives module: the
CB> xor operator on booleans

CB> let (^^) = (<>)

CB> Christoph Bauer

For type safety, it would be better to have 

let (^^) (x:bool) (y:bool) = x <> y

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Re: [Caml-list] xor on booleans

[Fabrice Le Fessant]

>  For type safety, it would be better to have 
>  
>  let (^^) (x:bool) (y:bool) = x <> y

Type safety is not lost, since (^^) is just equivalent to (<>), which
is polymorph. The polymorphic (^^) is better if I want to define my
own boolean type: type bool = True | False, and use (^^) with it.

- Fabrice
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Re: [Caml-list] xor on booleans

[Frederic De Jaeger]

>> For type safety, it would be better to have 
>> 
>> let (^^) (x:bool) (y:bool) = x <> y

FLF> Type safety is not lost, since (^^) is just equivalent to (<>), which
FLF> is polymorph. The polymorphic (^^) is better if I want to define my
FLF> own boolean type: type bool = True | False, and use (^^) with it.

That's the point, it is polymorph.
Personally, I rarely need to define my own boolean type.  
On the contrary, I like that such code is refused  (I mistakenly  have
typed two '^' instead of one. That  happens)

let s = "hello " ^^ "word" in ...

That's why I suggested to restrict the allowed type of (^^).
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Re: [Caml-list] xor on booleans

[Fabrice Le Fessant]

>  let s = "hello " ^^ "word" in ...
>  
>  That's why I suggested to restrict the allowed type of (^^).

Fortunately, the type-checker will tell you that you have made an
error as soon as you will try to use 's', which is a boolean and not a
string ...

- Fabrice
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Re: [Caml-list] xor on booleans

[Pierre Weis]

> That's why I suggested to restrict the allowed type of (^^).

Good: you will be glad with the upcoming version of Objective Caml,
that strictly restricts ( ^^ ) to be used with format strings only :)

(I'm joking, please don't flame)

Pierre Weis

INRIA, Projet Cristal, Pierre.Weis@inria.fr, http://pauillac.inria.fr/~weis/


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Re: [Caml-list] xor on booleans

[Pierre Weis]

> >  For type safety, it would be better to have 
> >  
> >  let (^^) (x:bool) (y:bool) = x <> y

Hem: as announced in a previous message about formats, ( ^^ ) is now
available in the current working version of Objective Caml to mean
concatenation of format strings (a long time desired feature for
format string constants).

So, please, use some other symbol for boolean xor: I would suggest <>
which is convenient and already defined in the language :)

Best regards,

Pierre Weis

INRIA, Projet Cristal, Pierre.Weis@inria.fr, http://pauillac.inria.fr/~weis/


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Re: [Caml-list] xor on booleans

[Fabrice Le Fessant]

>  > >  For type safety, it would be better to have 
>  > >  
>  > >  let (^^) (x:bool) (y:bool) = x <> y
>  
>  Hem: as announced in a previous message about formats, ( ^^ ) is now
>  available in the current working version of Objective Caml to mean
>  concatenation of format strings (a long time desired feature for
>  format string constants).
>  
>  So, please, use some other symbol for boolean xor: I would suggest <>
>  which is convenient and already defined in the language :)

By the way, it looks like the 'format' type has changed (4 args
instead of 3). This is a bit problematic, since some softwares must
use the CVS version of ocaml, only when compiled on Mac OS X (because
of the signal bug), but cannot stay compatible with the 3.06 distrib
because of this change in the format type. Will there be a new
official release soon ? It's not that important, the configure script
can detect and correct that, but it would be nice to have a
Jaguar-compatible official distrib of ocaml...

- Fabrice
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Re: [Caml-list] xor on booleans

[Damien Doligez]

On Thursday, February 6, 2003, at 03:39 PM, Fabrice Le Fessant wrote:

> By the way, it looks like the 'format' type has changed (4 args
> instead of 3). This is a bit problematic, since some softwares must
> use the CVS version of ocaml, only when compiled on Mac OS X (because
> of the signal bug),

You can install 3.06 on MacOSX, without the signal bug, if you
follow the instructions (and use the patch) given in this page:
< http://caml.inria.fr/caml-macosx-howto/index.html >

-- Damien

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[Caml-list] gdb with ocaml byte code on MacOSX

[David Brown]

On Fri, Feb 07, 2003 at 02:00:41PM +0100, Damien Doligez wrote:

> You can install 3.06 on MacOSX, without the signal bug, if you
> follow the instructions (and use the patch) given in this page:
> < http://caml.inria.fr/caml-macosx-howto/index.html >

Has anyone successfully gdb'd the bytecode interpreter under macosx?  I
don't seem to be able to set any breakpoints (I want to debug my C code
it calls).

Thanks,
Dave Brown
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Re: [Caml-list] gdb with ocaml byte code on MacOSX

[Damien Doligez]

On Monday, February 10, 2003, at 09:16 AM, David Brown wrote:

> Has anyone successfully gdb'd the bytecode interpreter under macosx?  I
> don't seem to be able to set any breakpoints (I want to debug my C code
> it calls).

I have no problems doing that, but I've only tried it on the debug
version of ocamlrun.  To build it:

cd .../byterun
make ocamlrund
cp ocamlrund /usr/local/bin/ocamlrun   (wherever you installed ocamlrun)
cp libcamlrund.a /usr/local/lib/ocaml/libcamlrun.a   (idem)
ranlib /usr/local/lib/ocaml/libcamlrun.a

Then you can compile with ocamlc and run your programs under gdb.
Be aware that the debug version is noticeably slower because the
memory manager does a lot of checking on its data structures.

-- Damien

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