jabbr

jabbr

[Paul Argentoff]

Hi ppl.

Did anyone write anything with jabbr? I have some questions.
-- 
Yours truly, WBR, Paul Argentoff.
Jabber:	paul@jabber.rtelekom.ru
RIPE:	PA1291-RIPE

Newbe question: Strings <-> char lists

[Juancarlo Añez]

How does one convert a char list to a string?

Why aren't functions for converting char lists to strings and back part of
the standard library.

Haskell allows treating any string as a char list. I don't know what it does
behind the scenes, but it is mighty convenient.

Juanco

Re: [Caml-list] Newbe question: Strings <-> char lists

[Alex Baretta]

Juancarlo Añez wrote:
> How does one convert a char list to a string?
> 
> Why aren't functions for converting char lists to strings and back part of
> the standard library.
> 
> Haskell allows treating any string as a char list. I don't know what it does
> behind the scenes, but it is mighty convenient.

As far as I now, Haskell actually implements strings as lists of 
characters, which might or might not be a useful abstraction of a 
string, but it is definitely inconvenient from the standpoint of 
computational and memory complexity. This explains the design choices 
behind the Ocaml string type as well as why a mapping from strings to 
char lists is not "standard" in Ocaml.

Alex

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RE: [Caml-list] Newbe question: Strings <-> char lists

[Juancarlo Añez]

Alex,

 | As far as I now, Haskell actually implements strings as 
 | lists of characters, 

I'm pretty sure that Haskell lets you *treat* strings as list of characters,
yet provides an efficient implementation of strings underneath.

 | This explains the design choices behind the Ocaml string 
 | type as well as why a mapping from strings to char lists is 
 | not "standard" in Ocaml.

I don't mind that strings are not lists in OCAML, but I would still like to
convert (through a function) a string to a char list. There are no functions
for doing that in the stdlib, and I haven't been able to write my own (the
string concatenation operator does not accept a char [naturally] and there
are no "append" or "insert" functions in the library).

Juanco

Re: [Caml-list] Newbe question: Strings <-> char lists

[Marcin 'Qrczak' Kowalczyk]

Juancarlo Añez <juanca@suigeneris.org> writes:

>  | As far as I now, Haskell actually implements strings as 
>  | lists of characters, 
>
> I'm pretty sure that Haskell lets you *treat* strings as list of
> characters, yet provides an efficient implementation of strings
> underneath.

No, it's really a lazy list of characters underneath. There are
non-standard extensions, packed strings, but they a separate type.

-- 
   __("<         Marcin Kowalczyk
   \__/       qrczak@knm.org.pl
    ^^     http://qrnik.knm.org.pl/~qrczak/

Re: [Caml-list] Newbe question: Strings <-> char lists

[Olivier Andrieu]

 Juancarlo Añez [Thu, 10 Feb 2005]:
 > 
 > How does one convert a char list to a string?

Several possibilities :
 - read the replies to your previous message
 - read the FAQ
 - subscribe to the beginner's list http://groups.yahoo.com/group/ocaml_beginners

 > Why aren't functions for converting char lists to strings and back
 > part of the standard library.

It's mighty inefficient in terms of memory : in a string one character
take approximately 1 byte, in a char list it needs 3 words (12 bytes
on IA32).

-- 
   Olivier