From bug-request at octave dot org Fri Feb  4 06:43:56 2005
Subject: Re: Should be able to say 'for (k=1:N)'
From: Paul Kienzle <pkienzle at users dot sourceforge dot net>
To: Julius Smith <jos at ccrma dot stanford dot edu>
Cc: bug at octave dot org
Date: Fri, 4 Feb 2005 07:48:28 -0500

This is not a parser inconsistency.

"for k = ..." is special syntax in the language.

The consistent thing is to consider (k=1:3) to be a value.

Whatever you expect from the statement:

	for 1:3, ... end

you should get the same thing from

	for (k=1:3), ... end

The following does look weird, but it is consistent:

	for k=x=1:3, k, x, end

It assigns x to [1,2,3], then lets k cycle over x.

- Paul

On Feb 2, 2005, at 4:45 PM, Julius Smith wrote:

> The octave session below illustrates a small parser inconsistency (see 
> fourth command line) that tends to bite C programmers. :-)
>
> > octave
> GNU Octave, version 2.1.64 (i686-pc-linux-gnu).
> ...
>
> octave:1> 1:4
> ans =
>
>   1  2  3  4
>
> octave:2> (1:4)
> ans =
>
>   1  2  3  4
>
> octave:3> (k=1:4)
> k =
>
>   1  2  3  4
>
> octave:4> for (k=1:4), k, end
> parse error:
>
>   syntax error
>
> >>> for (k=1:4), k, end
>                ^
>
> octave:4> for k=1:4, k, end
> k = 1
> k = 2
> k = 3
> k = 4
> octave:5>
>
>
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>
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-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
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