Re: [Caml-list] beginner question about pattern matching

["Matej Košík" <mail@matej-kosik.net>]

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Ok. Thank you all. I suspected as much but I wanted to check with someone else.

(Adding a note about n+1-st note about Ocaml quirks and moving on.)

    (* NOTE: This looks bad, but Ocaml (4.06 beta) does not allow me to do any better *)
    | [Rtag (f1,f2,f3,f4)] ->
         f1,f2,f3,f4

On 10/19/2017 04:34 PM, Gabriel Scherer wrote:
> This is a small hiccup with the OCaml (non-revised) syntax:
> 
>   | Foo of bar * baz * blah
> 
> and
> 
>   | Foo of (bar * baz * blah)
> 
> are not equivalent, and only the latter allows to do what you want.
> 
> 
> On Thu, Oct 19, 2017 at 3:38 PM, Matej Košík <mail@matej-kosik.net> wrote:
>> Hi,
>>
>> I am trying to do simple pattern matching of these values:
>> https://github.com/ocaml/ocaml/blob/trunk/parsing/parsetree.mli#L145
>>
>> What I would like to do is:
>>
>>    | [Rtag the_whole_4_tuple] ->
>>        the_whole_4_tuple
>>
>> However, when I try to do that, I am getting:
>>
>>   Error: The constructor Rtag expects 4 argument(s),
>>          but is applied here to 1 argument(s)
>>
>> This:
>>
>>     | [Rtag (f1,f2,f3,f4)] ->
>>         f1,f2,f3,f4
>>
>> of course works but (regardless of the chosen bound variable names), it looks amateurish.
>>
>> What's the right way to do this?
>> (I would like just to bind a 4-tuple and then return it)
>>
>> (Apologies in advance for a stupid question.)
>>
> 


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