[Caml-list] what is here the syntax error

[Caml-list] what is here the syntax error

[Roelof Wobben]

Hello,

I know this question must be asked on the beginners list but I still did 
not get approved after I left the list.

I try again to learn Ocaml and Im stuck at exercise 1 of the 99 ocaml 
problems.

Here is my solution :

let rec last list =
    match list with
      []  -> None
      [x] -> Some x
      [_]   -> last [_::t] ;;

But now I see a syntax error on the [x] part.

Can anyone explain to me what I did wrong ?

Roelof

Re: [Caml-list] what is here the syntax error

[Francois Berenger]

-------- Forwarded Message --------
Subject: Re: [Caml-list] what is here the syntax error
Date: Wed, 05 Nov 2014 13:14:54 +0100
From: Francois Berenger <francois.berenger@inria.fr>
To: Roelof Wobben <r.wobben@home.nl>

On 11/05/2014 12:45 PM, Roelof Wobben wrote:
> Hello,
>
> I know this question must be asked on the beginners list but I still did
> not get approved after I left the list.
>
> I try again to learn Ocaml and Im stuck at exercise 1 of the 99 ocaml
> problems.
>
> Here is my solution :
>
> let rec last list =
>     match list with
>       []  -> None
>       [x] -> Some x
>       [_]   -> last [_::t] ;;

Your last line is wrong:
[_]   -> last [_::t] ;;

try to replace it with:
x :: xs -> last xs ;;

> But now I see a syntax error on the [x] part.
>
> Can anyone explain to me what I did wrong ?
>
> Roelof
>
>

-- 
Regards,
Francois.

Re: [Caml-list] what is here the syntax error

[Pierrick Couderc]

[-- Attachment #1: Type: text/plain, Size: 1677 bytes --]

>
> Your last line is wrong:
> [_]   -> last [_::t] ;;
>
> try to replace it with:
> x :: xs -> last xs ;;


Actually, that's the syntax of the pattern mathing that is wrong (but this
would also raise en error) : each case should begin with a '|' (the pipe is
optional for the first line).
i.e. :
match list with
    [] -> None
  | [x] -> Some x
  | _ :: xs -> last xs

Pierrick

2014-11-05 13:15 GMT+01:00 Francois Berenger <francois.berenger@inria.fr>:

>
>
>
> -------- Forwarded Message --------
> Subject: Re: [Caml-list] what is here the syntax error
> Date: Wed, 05 Nov 2014 13:14:54 +0100
> From: Francois Berenger <francois.berenger@inria.fr>
> To: Roelof Wobben <r.wobben@home.nl>
>
> On 11/05/2014 12:45 PM, Roelof Wobben wrote:
>
>> Hello,
>>
>> I know this question must be asked on the beginners list but I still did
>> not get approved after I left the list.
>>
>> I try again to learn Ocaml and Im stuck at exercise 1 of the 99 ocaml
>> problems.
>>
>> Here is my solution :
>>
>> let rec last list =
>>     match list with
>>       []  -> None
>>       [x] -> Some x
>>       [_]   -> last [_::t] ;;
>>
>
> Your last line is wrong:
> [_]   -> last [_::t] ;;
>
> try to replace it with:
> x :: xs -> last xs ;;
>
>  But now I see a syntax error on the [x] part.
>>
>> Can anyone explain to me what I did wrong ?
>>
>> Roelof
>>
>>
>>
> --
> Regards,
> Francois.
>
>
>
>
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa.inria.fr/sympa/arc/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
>



-- 
Pierrick COUDERC

*PhD Student at OCamlPro / Ensta*

[-- Attachment #2: Type: text/html, Size: 3622 bytes --]