[erlang-questions] separators before end

David Mercer <>
Wed Sep 19 19:07:15 CEST 2007


> The fact that Erlang doesn't *HAVE* statements.  It only has
> expressions.  What is the value of an empty expression?

Good point.

> Where Erlang *does* need to allow extra semicolons is at the
> *beginnings* of ifs, cases, and receives, so you can write
> 	case e0 of
> 	  ; p1 when g1 -> e1
> 	  ; ...
> 	  ; pn when gn -> en
> 	end
> and be sure of having your punctuation right.

I prefer this, too.

Cheers,

David


-----Original Message-----
From: 
[mailto:] On Behalf Of ok
Sent: Wednesday, September 19, 2007 01:00
To: Erlang-Questions (E-mail)
Subject: Re: [erlang-questions] separators before end


On 19 Sep 2007, at 3:33 pm, Doug Edmunds wrote:

> Can someone tell me why it would be so difficult for Erlang
> to allow commas and semi-colons before the word ''end"?

Syntactically it would be easy.
>
> If there is a syntax error waiting to happen it is doing
> a copy/paste that doesn't add or take away a comma or
> semi-colon.

This doesn't happen to me, but I'm not a *heavy* user of Erlang,
so evidence from people who are would be useful.
> What is so bad about having an empty statement?

The fact that Erlang doesn't *HAVE* statements.  It only has
expressions.  What is the value of an empty expression?
Should
	if ... -> E1, ; ... -> En, ; end
have the same value as
	if ... -> E1 ; ... -> En end
and if so, how come the empty expression has so many different values?
If not, why not?

Where Erlang *does* need to allow extra semicolons is at the
*beginnings* of ifs, cases, and receives, so you can write
	case e0 of
	  ; p1 when g1 -> e1
	  ; ...
	  ; pn when gn -> en
	end
and be sure of having your punctuation right.

>
>
> --dae
>
> _______________________________________________
> erlang-questions mailing list
> 
> http://www.erlang.org/mailman/listinfo/erlang-questions

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