unicode in string literals - Erlang Programming

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Date: Mon, 30 Jul 2012 15:06:38 +0200
Message-ID: <CAKrexV+D8WdibhyEMdzxXjXpois816-S2n9_eo4YA5LTu8m...@mail.gmail.com>
From: CGS <cgsmcml...@gmail.com>
To: Joe Armstrong <erl...@gmail.com>
Cc: Erlang <erlang-questi...@erlang.org>
Subject: Re: [erlang-questions] unicode in string literals
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Hi Joe,

You may try unicode module:

test() -> unicode:characters_to_list("a=E2=88=9Eb",utf8).

which will return the desired list [97,8734,98]. As Richard said, the
default is Latin-1 (0-255 integers).

As for binaries, the same problem (assuming Latin-1).

CGS




On Mon, Jul 30, 2012 at 2:35 PM, Joe Armstrong <erl...@gmail.com> wrote:

> What is a literal string in Erlang? Originally it was a list of
> integers, each integer
> being a single character code - this made strings very easy to work with
>
> The code
>
>     test() -> "a=E2=88=9Eb".
>
> Compiles to code which returns the list
> of integers [97,226,136,158,98].
>
> This is very inconvenient. I had expected it to return
> [97, 8734, 98]. The length of the list should be 3 not 5
> since it contains three unicode characters not five.
>
> Is this a bug or a horrible misfeature?
>
> So how can I make a string with the three characters 'a' 'infinity' 'b'
>
> test() -> "a\x{221e}b"        is ugly
>
> test() -> <<"a=E2=88=9Eb"/utf8>>   seems to be a bug
>                                             it gives an error in the
> shell but is ok in compiled code and
>                                             returns
> <<97,195,162,194,136,194,158,98>> which is
>                                             very strange
>
> test() -> [$a,8734,$b]       is ugly
>
> /Joe
> _______________________________________________
> erlang-questions mailing list
> erlang-questi...@erlang.org
> http://erlang.org/mailman/listinfo/erlang-questions
>

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Hi Joe,<div><br></div><div>You may try unicode module:</div><div><br></div>=
<div>test() -&gt; unicode:characters_to_list(&quot;a=E2=88=9Eb&quot;,utf8).=
</div><div><br></div><div>which will return the desired list=C2=A0[97,8734,=
98]. As Richard said, the default is Latin-1 (0-255 integers).</div>
<div><br></div><div>As for binaries, the same problem (assuming Latin-1).</=
div><div><br></div><div>CGS</div><div><br></div><div><br></div><div><br><br=
><div class=3D"gmail_quote">On Mon, Jul 30, 2012 at 2:35 PM, Joe Armstrong =
<span dir=3D"ltr">&lt;<a href=3D"mailto:erl...@gmail.com" target=3D"_blank"=
>erl...@gmail.com</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">What is a literal string in Erlang? Original=
ly it was a list of<br>
integers, each integer<br>
being a single character code - this made strings very easy to work with<br=
>
<br>
The code<br>
<br>
=C2=A0 =C2=A0 test() -&gt; &quot;a=E2=88=9Eb&quot;.<br>
<br>
Compiles to code which returns the list<br>
of integers [97,226,136,158,98].<br>
<br>
This is very inconvenient. I had expected it to return<br>
[97, 8734, 98]. The length of the list should be 3 not 5<br>
since it contains three unicode characters not five.<br>
<br>
Is this a bug or a horrible misfeature?<br>
<br>
So how can I make a string with the three characters &#39;a&#39; &#39;infin=
ity&#39; &#39;b&#39;<br>
<br>
test() -&gt; &quot;a\x{221e}b&quot; =C2=A0 =C2=A0 =C2=A0 =C2=A0is ugly<br>
<br>
test() -&gt; &lt;&lt;&quot;a=E2=88=9Eb&quot;/utf8&gt;&gt; =C2=A0 seems to b=
e a bug<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 it gives an error in the<br>
shell but is ok in compiled code and<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 returns<br>
&lt;&lt;97,195,162,194,136,194,158,98&gt;&gt; which is<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 very strange<br>
<br>
test() -&gt; [$a,8734,$b] =C2=A0 =C2=A0 =C2=A0 is ugly<br>
<br>
/Joe<br>
_______________________________________________<br>
erlang-questions mailing list<br>
<a href=3D"mailto:erlang-questi...@erlang.org">erlang-questi...@erlang.org<=
/a><br>
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blank">http://erlang.org/mailman/listinfo/erlang-questions</a><br>
</blockquote></div><br></div>

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