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From: Pierre Weis <pierre.weis@inria.fr>
Message-Id: <200211291848.TAA03861@pauillac.inria.fr>
Subject: Re: [Caml-list] small exercise
In-Reply-To: <3DE78822.7020304@univ-savoie.fr> from Christophe Raffalli at "Nov 29, 102 04:30:42 pm"
To: raffalli@univ-savoie.fr (Christophe Raffalli)
Date: Fri, 29 Nov 2002 19:48:20 +0100 (MET)
Cc: altavillasalvatore@libero.it, caml-list@inria.fr
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> altavillasalvatore@libero.it wrote:
> > Hi all,
> > 
> > I do not succeed to develop the following exercise:
> > I have need of your aid.
> > 
> > 
> > 
> > input:  string    "1.15.120.13.43.35.340.190.0"
> > 
> > output: int array=  [| 1; 15; 120; 13; 43; 35; 340; 190; 0; |] 
> > 
> >   : string -> int array
> > 
> > 
> > Regards.
[...]
> Just a hint look at the documentation of the following functions:
> 
> module        | function
> ------------------------------
> str           | split
> list          | map
> pervasives    | int_of_string
> array         | of_list
> 
> The answer fits on one (long) line.
> -- 
> Christophe Raffalli

I guess, you forgot the most appropriate module for the exercicise: Scanf.

Indeed, scanning the given input string to obtain the expected vector
only using Scanf.scanf is interesting and not completely trivial.

An additional question could be: write a general polymorphic reader
that can input vectors with elements of any simple basic type (say
bool, int, string, char, float). Define a string reader via partial
application of the polymorphic reader.

Last but not least could be: generalize (if necessary) the polymorphic
reader to read vectors of any given type. Apply this function to read
matrices of floating point numbers. Discuss the use of Scanf in place
of a combination of modules Str, List, Pervasives, Array, ...

Mmm. A trivial exercicise could show up to be interesting afterwards :)

Pierre Weis

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


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