On 6 August 2014 14:15, Elias Mårtenson wrote:
> My suggestion is that niladic lambda functions will not be allowed at all.
> Instead, they will be interpreted as monadic functions that ignore their
> argument.
That's consistent with the behaviour of Dyalog.
Jay.
Jay,
I also noticed that Dyalog does not allow self-evaluation of niladic
lambdas. I.e. the expression {1} on its own does not evaluate to 1, but
rather to something else (it's displayed as {1}, and I'm not sure you can
do anything with it other than assigning it to a variable).
Regards,
Elias
Elias,
There is no such thing as a niladic lambda in Dyalog.
In Dyalog "niladic lambda functions [are] not [...] allowed at all.
Instead, they [are] interpreted as monadic functions that ignore their
argument."
So {1} is a monadic function. You can evaluate it by applying it to an argument:
Jay,
That makes sense. So the only benefit of the GNU APL approach is that it
allows the definition of niladic functions by assigning from a lambda.
My personal opinion is that that's barely a benefit, and that the Dyalog
approach is much better.
Perhaps Jürgen is willing to reconsider?
Regards
> So the only benefit of the GNU APL approach is that it
> allows the definition of niladic functions by assigning from a lambda.
I don't understand. You can't use assignment to name a niladic lambda
in GNU APL, because it will be evaluated before the assignment
happens:
f←{1⊣⎕←2}
2
f
No, you definitely understand. It's me that don't understand. :-)
Regards,
Elias
On 7 August 2014 16:52, Jay Foad wrote:
> > So the only benefit of the GNU APL approach is that it
> > allows the definition of niladic functions by assigning from a lambda.
>
> I don't understand. You can't use a
Hi,
actually you can. There are 2 points in time that are relevant:
1. tokenization time (when the statement text is converted into tokens).
At this
time (in GNU APL) the {} is detected and converted into a (possibly
niladic) defined function.
2. execution time (when the statement is execute
What function is it? How can I execute that function?
The only reasonable answers I can think of are "it's the function
{1⊣⎕←2}" and "you can execute it by typing f and hitting ENTER", but
that's clearly not true because when I type f and hit ENTER I don't
see the number 2 printed to the session:
Hi Jay,
the functions are called λ1. λ2, ... for the first, second, ... lambda.
However the names above are not entered into the symbol table, therefore
you can't call them via their names. The function bodies can't be
displayed with ⎕CR,
but may show up in error messages:
* ∇foo**
**[1]
Hi Elias,
sorry, probably committed it to my local 1.3 .branch rather than to 1.4.
Should be in SVN 423 file InputFile.hh.
/// Jürgen
On 08/07/2014 06:20 AM, Elias Mårtenson wrote:
OK, I have updated everything and the code works fine. There is only
one more outstanding issue and that is that
Hi,
for me it is not at all clear why *{1} 0* should eat (and discard) its
right argument.
In other words why would *{1} 0 *behave differently than *N 0 *with *N*
being a niladic function?
That would create new rules in the APL syntax without a need. I would
rather opt for David's
"princi
But having {⎕←'foo'} REPEAT 10 result in an error is certainly surprising
to me. Also, if you look at where lambdas are actually used, the current
behaviour results in more surprises than the Dyalog model. Even
disregarding the surprises part (which I can agree is often a matter of
personal taste),
Right. Even in GNU APL monadic lambdas consume and ignore any left
argument you give them, so you could argue that it's consistent for
niladic lambdas to consume and ignore both arguments.
Jay.
On 7 August 2014 14:53, Elias Mårtenson wrote:
> And, one could argue that knowing that lambdas are al
Awesome, it works great. I've implemented this in the emacs mode native
code now.
You can merge it into mainline, and I have no longer anything that holds
back a 1.4 release.
Regards,
Elias
On 7 August 2014 20:33, Juergen Sauermann
wrote:
> Hi Elias,
>
> sorry, probably committed it to my loc
Hi,
my point is that there should be no difference between lambdas and
defined functions.
The reason that the left argument is ignored is that dyadic functions
can be called monadically
(the presence of the left argument *can* be checked with *⎕NC* but it
does not have to be checked.)
But ev
Hi Elias,
thanks! I got a few errors, and no file seems to have been changed?
/// Jürgen
make -C src git-pull
make[1]: Entering directory `/home/eedjsa/apl/apl-1.4/src'
make -C emacs_mode git-pull
make[2]: Entering directory `/home/eedjsa/apl/apl-1.4/src/emacs_mode'
git pull
error: refs/heads
I honestly have no idea what happens there. The error message seems to come
from the SQL library though, not from emacs-mode.
I recommend that you use the subversion mirror for a plain export though
(this is something svn does better than git). Delete the directory
completely, and then use the fol
Sorry for the inline code. GMail's web client - for some unknown reason
this morning - won't let me attach a file.
-- begin lamkins-fnhdr.apl
⍝!
∇foo;a;b ⍝;c
1
∇
-- end lamkins-fnhdr.apl
)load lamkins-fnhdr.apl
loading )DUMP file /home/dlamkins/APL/workspaces/lamkins-fnhdr.apl...
WAS
Hello,
I am happy to announce that GNU APL 1.4 has been released.
This release contains:
* an interface to mySQL and Postgres databases (thanks to Elias)
* two component file systems as demanded by ISO 13751 (thanks to Blake
and David)
* a centralized server for shared variables (APserver)
Thank you very much!
On Thu, Aug 7, 2014 at 12:57 PM, Juergen Sauermann <
juergen.sauerm...@t-online.de> wrote:
> Hello,
>
> I am happy to announce that GNU APL 1.4 has been released.
>
> This release contains:
>
> * an interface to mySQL and Postgres databases (thanks to Elias)
>
> * two comp
Great job Jürgen..and Elias, Blake, and David.
respect…
Peter
On 2014-08-07, at 1:57 PM, Juergen Sauermann
wrote:
> Hello,
>
> I am happy to announce that GNU APL 1.4 has been released.
>
> This release contains:
>
> * an interface to mySQL and Postgres databases (thanks to Elias)
>
> *
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