right-associating infix application operator camlp4 extension

right-associating infix application operator camlp4 extension

[Quôc Peyrot]

Hello,
Is there any existing camlp4 extensions to define a $ haskell-like  
operator?

example:
f x $ y z would be equivalent to f x (y z)
or
print_endline $ string_of_int x would be equivalent to print_endline  
(string_of_int x)

Thanks,

-- 
Best Regards,
Quôc

Re: [Caml-list] right-associating infix application operator camlp4 extension

[Christian Lindig]

Am 07.08.2005 um 01:03 schrieb Quôc Peyrot:

> Is there any existing camlp4 extensions to define a $ haskell-like 
> operator?

You don't need CamlP4 for this. You could define in OCaml:

	let (@@) f x = f x

Now you can write:
	
	 print_endline @@ string_of_int x

-- Christian

Re: [Caml-list] right-associating infix application operator camlp4 extension

[osiire]

Hi.

On Sat, 6 Aug 2005 16:03:55 -0700
In <7B0AADBE-23D8-4C63-ABE7-75360C874E13@lrde.epita.fr>
Quôc Peyrot <chojin@lrde.epita.fr> wrote:
> Is there any existing camlp4 extensions to define a $ haskell-like  
> operator?

Maybe "@" and "^" are right-associated.

# let ( ^$ ) f x = f x;;
val ( ^$ ) : ('a -> 'b) -> 'a -> 'b = <fun>
# print_string ^$ List.fold_left (fun x sum -> sum ^ x) "" ^$ ["1";"2";"3"];;
321- : unit = ()

# let ( @$ )  f x = f x;;
val ( @$ ) : ('a -> 'b) -> 'a -> 'b = <fun>
#  print_string @$ List.fold_left (fun x sum -> sum ^ x) "" @$ ["1";"2";"3"];;
321- : unit = ()

---
 osiire

Re: [Caml-list] right-associating infix application operator camlp4 extension

[Jean-Marie Gaillourdet]

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Hi,

osiire@k8.dion.ne.jp schrieb:
> Maybe "@" and "^" are right-associated.
> 
> # let ( ^$ ) f x = f x;;
> val ( ^$ ) : ('a -> 'b) -> 'a -> 'b = <fun>
> # print_string ^$ List.fold_left (fun x sum -> sum ^ x) "" ^$ ["1";"2";"3"];;
> 321- : unit = ()
> 
> # let ( @$ )  f x = f x;;
> val ( @$ ) : ('a -> 'b) -> 'a -> 'b = <fun>
> #  print_string @$ List.fold_left (fun x sum -> sum ^ x) "" @$ ["1";"2";"3"];;
> 321- : unit = ()

I think this peace of code make the distinction clearer.

# let (^) a b = a,b;;
val ( ^ ) : 'a -> 'b -> 'a * 'b = <fun>
# let (-) a b = a,b;;
val ( - ) : 'a -> 'b -> 'a * 'b = <fun>

Compare the types of the following to expressions:

# 1 - 2 - 3;;
- - : (int * int) * int = ((1, 2), 3)
# 1 ^ 2 ^ 3;;
- - : int * (int * int) = (1, (2, 3))
#

Is that kind of behaviour documented? I wasn't able to find it in the
docs. Which other operator names are right associative?

Jean-Marie Gaillourdet

- --
"Make everything as simple as possible, but not simpler" (A. Einstein)
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Re: [Caml-list] right-associating infix application operator camlp4 extension

[David MENTRE]

Hello,

2005/8/10, Jean-Marie Gaillourdet <jmg@gaillourdet.net>:
> Is that kind of behaviour documented? I wasn't able to find it in the
> docs. Which other operator names are right associative?

See the OCaml manual :
 http://caml.inria.fr/pub/docs/manual-ocaml/manual015.html

"""
For infix and prefix symbols, we write ``*...'' to mean ``any symbol
starting with *''.
"""

Associativity is given in the table.

Yours,
d.

Re: [Caml-list] right-associating infix application operator camlp4 extension

[Quôc Peyrot]

On Aug 10, 2005, at 12:50 AM, David MENTRE wrote:

> Hello,
>
> 2005/8/10, Jean-Marie Gaillourdet <jmg@gaillourdet.net>:
>
>> Is that kind of behaviour documented? I wasn't able to find it in the
>> docs. Which other operator names are right associative?
>>
>
> See the OCaml manual :
>  http://caml.inria.fr/pub/docs/manual-ocaml/manual015.html

Thanks a lot for the answers.
Strangely I couldn't find $ in this documentation, but
let ($) f x = f x
seems to work.

-- 
Best Regards,
Quôc

Re: [Caml-list] right-associating infix application operator camlp4 extension

[Stephane Glondu]

On Wednesday 10 August 2005 20:04, Quôc Peyrot wrote:
> Thanks a lot for the answers.
> Strangely I couldn't find $ in this documentation, but
> let ($) f x = f x
> seems to work.

You can use $ as an infix operator according to:
http://caml.inria.fr/pub/docs/manual-ocaml/manual009.html

And it is left-associative, as said in:
http://caml.inria.fr/pub/docs/manual-ocaml/manual015.html

But as far as I understood, Haskell's $ is right-associative.

-- 
Stephane Glondu

Re: [Caml-list] right-associating infix application operator camlp4 extension

[Christian Lindig]

On Aug 11, 2005, at 5:04 AM, Quôc Peyrot wrote:

> Thanks a lot for the answers.
> Strangely I couldn't find $ in this documentation, but
> let ($) f x = f x
> seems to work.

This does not work; you need a right associative operator:

# let ($) f x = f x;;
val ( $ ) : ('a -> 'b) -> 'a -> 'b = <fun>
# (-) 3 $ (/) 4 $ 2 ;;
This expression has type int -> int but is here used with type int

# let (@@) f x = f x;;
val ( @@ ) : ('a -> 'b) -> 'a -> 'b = <fun>
# (-) 3 @@ (/) 4 @@ 2 ;;
- : int = 1

This is the right result for 3-(4/2)=1.

-- Christian