|From:||Dr . Jürgen Sauermann|
|Subject:||Re: Comments on GNU APL|
|Date:||Fri, 10 Jan 2020 14:17:28 +0100|
|User-agent:||Mozilla/5.0 (X11; Linux i686; rv:60.0) Gecko/20100101 Thunderbird/60.6.1|
thank you very much for your comments. Please see some
remarks from my side inline below.
On 1/9/20 8:53 PM, Mr. Brian B. McGuinness wrote:
Interesting. This seems to be related to platform on which
GNU APL runs. At the time when this was implemented 64-bit
GNU/Linux was not as common as it is today (and even on my
current 64-bit system this does not happen. Apparently you
somehow start GNU APL in a way that ⎕FXes the libemacs
native function automatically (I am a notorious vi user, thats probably
why I missed it).
I will look into this, please let me know:
1. what is your platform, and
2. how (command line arguments, )COUTINUE workspace) do you
start GNU APL when this error occurs?
Actually )SAVE and )DUMP use the same function for serializing floating
point values. As Kacper and Jay pointed out, the precision is lost in the
sec2rad ← 4.8481368110953599359e¯6
You can provide as many significant digits as you like, but the precision
will always be limited by the internal representation of floating point numbers.
This representation is platform specific and will, in most cases, be the precision
of IEEE 754 doubles with 64-bits (the precision is then around 51 bits or 16
As far as defined functions are concerned, I see no reason why
there should be arbitrary restrictions on the arguments of defined
functions. And a genuine axis specification can already today be
more than a simple integer scalar, for example X in ⊃[X] B or
'123'[''] , the latter already valid long before APL2.
Initially ⎕FIO did allow only integer scalars as function numbers. This
was, due to the large number of functions that ⎕FIO provides, rather
cumbersome to read and the fix for this was the FILE_IO.apl workspace
which wrapped every ⎕FIO function into a corresponding FIO∆ function.
So, to e.g. fopen() a file for reading we have 3 alternatives:
My personal taste is that ⎕FIO is entirely unreadable and FIO∆fopen
is readable but the need to )COPY FIO.aplis somewhat annoying. I would
argue that the third option, ⎕FIO['fopen'], is the most readable and
The honor is Dyalog's who apparently came up with this and Elias'
(if I remember correctly) to propose it for GNU APL.
I am already lost when it comes to understand what the above means.
My guts feeling is that importing an absolutely ugly syntax like regular
expressions into a beautiful language like APL might make the
inventor of APL rotate in his grave. I already felt guilty when turning the
native function for regular expressions the system function ⎕RE. This
was already a compromise and I would prefer not to drive it any further.
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