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Re: Attaching an alist to a grob
From: |
Urs Liska |
Subject: |
Re: Attaching an alist to a grob |
Date: |
Thu, 15 Jan 2015 13:04:20 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 |
Am 14.01.2015 um 14:47 schrieb Mattes:
Am Mittwoch, 14. Januar 2015 13:56 CET, Urs Liska <address@hidden> schrieb:
OK, I see.
But somehow it feels wrong that
#(display annotation? some-obj)
doesn't produce #t but the content of "location".
Should I ignore that feeling?
If you intended to write
#(display (annotation? some-obj))
Oops, yes, that's what I intended to write in the above message.
Of course that's not what I'd write in real code where I'd only need
#(if (annotation? some-obj)).
then, yes, ignore that feeling. Scheme, like all Lisps (that I know of) has
generalized booleans,
so anything that's not explicitly false [1] is considered true. Because of this
you hardly ever see
a litteral #t in Scheme code.
OK. I'll try to internalize this, and of course I'll update the code ASAP.
Thanks again for the different input
Urs
Cheers, RalfD
[1] while Scheme considers #f to be the only _false_ value, Common Lisp et al.
also consider
the empty list '() as a valse value.
Urs
- Re: Attaching an alist to a grob, (continued)
Re: Attaching an alist to a grob, Urs Liska, 2015/01/14
- Re: Attaching an alist to a grob, Richard Shann, 2015/01/14
- Re: Attaching an alist to a grob, Urs Liska, 2015/01/14
- Re: Attaching an alist to a grob, Richard Shann, 2015/01/14
- Re: Attaching an alist to a grob, Mattes, 2015/01/14
- Re: Attaching an alist to a grob, Urs Liska, 2015/01/14
- Re: Attaching an alist to a grob, Mattes, 2015/01/14
- Re: Attaching an alist to a grob,
Urs Liska <=