On Mon, Feb 20, 2012 at 06:28:55AM -0500, Carl Eastlund wrote:
> If (implies a b ... z) is equivalent to (implies a (implies b ... z)), then
> it is also equivalent to (implies (and a b ...) z). In which case, the
> 1-ary case should be clear: just return z. In truth, it is not really
> necessary
Oh, good point! I've adjusted implies to just take two arguments.
Meanwhile, I've also added a binary xor. It returns the non-#f
argument when exactly one of the arguments is #f and otherwise returns
#f. Comments welcome.
Robby
On Mon, Feb 20, 2012 at 5:28 AM, Carl Eastlund wrote:
> If (implies
If (implies a b ... z) is equivalent to (implies a (implies b ... z)), then
it is also equivalent to (implies (and a b ...) z). In which case, the
1-ary case should be clear: just return z. In truth, it is not really
necessary to have n-ary implies if you're willing to nest the (and ...)
explicit
On Sun, Feb 19, 2012 at 7:10 PM, Neil Toronto wrote:
> On 02/19/2012 06:05 AM, Robby Findler wrote:
>>
>> On Sun, Feb 19, 2012 at 12:30 AM, Gary Baumgartner
>> wrote:
>>>
>>> On a more productive note: in Racket code I define and use 'implies' a
>>> lot,
>>> often conjoined, for predicates. It's
On 02/19/2012 06:05 AM, Robby Findler wrote:
On Sun, Feb 19, 2012 at 12:30 AM, Gary Baumgartner wrote:
On a more productive note: in Racket code I define and use 'implies' a lot,
often conjoined, for predicates. It's mainly of declarative value, which is
perhaps why it's uncommon in impleme
On Sun, Feb 19, 2012 at 03:17:49PM -0600, Robby Findler wrote:
>
> If it helps, the usual English construction is "neither A nor B", so
> maybe that's a good memory clue.
That's what I needed! I don't think I'll ever forget now.
-- hendrik
Racket Users list:
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On Sun, Feb 19, 2012 at 1:03 PM, Hendrik Boom wrote:
> On Sun, Feb 19, 2012 at 07:05:37AM -0600, Robby Findler wrote:
>> On Sun, Feb 19, 2012 at 12:30 AM, Gary Baumgartner
>> wrote:
>> > On a more productive note: in Racket code I define and use 'implies' a lot,
>> > often conjoined, for predic
On Sun, Feb 19, 2012 at 02:03:51PM -0500, Hendrik Boom wrote:
> On Sun, Feb 19, 2012 at 07:05:37AM -0600, Robby Findler wrote:
> > On Sun, Feb 19, 2012 at 12:30 AM, Gary Baumgartner
> > wrote:
> > > On a more productive note: in Racket code I define and use 'implies' a
> > > lot,
> > > often co
On Sun, Feb 19, 2012 at 17:03, Hendrik Boom wrote:
>
> The trouble is, I can never remember which of 'nand' and 'nor' is
> which. Either of them could mean 'neither'. But I do know what
> 'neither' means.
>
>
Think of them as composed boolean functions:
- nand is "not and"
- nor is "not or"
`a
On Sun, Feb 19, 2012 at 07:05:37AM -0600, Robby Findler wrote:
> On Sun, Feb 19, 2012 at 12:30 AM, Gary Baumgartner
> wrote:
> > On a more productive note: in Racket code I define and use 'implies' a lot,
> > often conjoined, for predicates. It's mainly of declarative value, which is
> > perhap
On Sun, Feb 19, 2012 at 12:30 AM, Gary Baumgartner wrote:
> On a more productive note: in Racket code I define and use 'implies' a lot,
> often conjoined, for predicates. It's mainly of declarative value, which is
> perhaps why it's uncommon in implementation despite how common it is in
> speci
On Sun, Feb 19, 2012 at 07:30, Gary Baumgartner wrote:
> On Sat, Feb 18, 2012 at 09:02:41PM -0500, Stephen Bloch wrote:
> [...]
> > I see a lot of my students doing this -- in whatever language -- because
> they think of Booleans as a way to decide which of two things to DO, rather
> than as legi
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