• Jeremiah Glover (77/77) Aug 08 2020 I've been wanting to put together a programming to teach D. The
• Johan (5/17) Aug 08 2020 Seems to work fine with LDC 1.22:
• Steven Schveighoffer (11/13) Aug 08 2020 You are using an old version of the compiler. formattedRead used to

Jeremiah Glover <jeremiah7glover gmail.com> writes:

I've been wanting to put together a programming to teach D. The 
raspberry pi seemed like a good computer to use so everyone could 
be guaranteed to have a computer to practice on. I've had some 
trouble, however, getting a test project to compile, and the 
first culprit lives in std.format.

I tried both LDC and GDC by using `sudo apt install ldc` and 
`sudo apt install gdc`

compiling my test file with ldc gives these errors

/usr/lib/ldc/arm-linux-gnueabihf/include/d/std/format.d(620): 
Error: can only * a pointer, not a 'int'
/usr/lib/ldc/arm-linux-gnueabihf/include/d/std/format.d(631): 
Error: can only * a pointer, not a 'int'
/usr/lib/ldc/arm-linux-gnueabihf/include/d/std/format.d(620): 
Error: using * on an array is no longer supported; use 
*(_param_2).ptr instead
/usr/lib/ldc/arm-linux-gnueabihf/include/d/std/format.d(631): 
Error: using * on an array is no longer supported; use 
*(_param_2).ptr instead
/usr/lib/ldc/arm-linux-gnueabihf/include/d/std/format.d(633): 
Error: template instance std.format.formattedRead!(char[], char, 
string) error instantiating
diceware.d(26):        instantiated from here: 
formattedRead!(char[], char, int, string)
diceware.d(39): Error: template std.format.formattedRead cannot 
deduce function from argument types !()(string, string, int), 
candidates are:
/usr/lib/ldc/arm-linux-gnueabihf/include/d/std/format.d(588):     
    std.format.formattedRead(R, Char, S...)(ref R r, const(Char)[] 
fmt, S args)

compiling with gdc gives these errors:

/usr/lib/gcc/arm-linux-gnueabihf/6/include/d/std/format.d:618:26: 
error: can only * a pointer, not a 'int'
          alias A = typeof(*args[0]);
                           ^
/usr/lib/gcc/arm-linux-gnueabihf/6/include/d/std/format.d:629:13: 
error: can only * a pointer, not a 'int'
              *args[0] = unformatValue!(A)(r, spec);
              ^
/usr/lib/gcc/arm-linux-gnueabihf/6/include/d/std/format.d:618:26: 
error: using * on an array is no longer supported; use 
*(_param_2).ptr instead
          alias A = typeof(*args[0]);
                           ^
/usr/lib/gcc/arm-linux-gnueabihf/6/include/d/std/format.d:629:13: 
error: using * on an array is no longer supported; use 
*(_param_2).ptr instead
              *args[0] = unformatValue!(A)(r, spec);
              ^
/usr/lib/gcc/arm-linux-gnueabihf/6/include/d/std/format.d:631:33: 
error: template instance std.format.formattedRead!(char[], char, 
string) error instantiating
          return 1 + formattedRead(r, spec.trailing, args[1 .. $]);
                                  ^
/home/pi/diceware/diceware.d:26:22: note: instantiated from here: 
formattedRead!(char[], char, int, string)
          formattedRead(line, "%d\t%s", dummy, word);
                       ^
/home/pi/diceware/diceware.d:39:18: error: template 
std.format.formattedRead cannot deduce function from argument 
types !()(string, string, int), candidates are:
      formattedRead(readln.strip, "%d", num_words);
                   ^
/usr/lib/gcc/arm-linux-gnueabihf/6/include/d/std/format.d:586:6: 
note: std.format.formattedRead(R, Char, S...)(ref R r, 
const(Char)[] fmt, S args)
  uint formattedRead(R, Char, S...)(ref R r, const(Char)[] fmt, S 
args)

You can find my test file and a text file that makes the program 
work at https://github.com/d-us-vb/diceware. It compiles without 
warning on my (x86) laptop.

Looking at format.d on the RPi and on my laptop, I noticed that 
the desktop version of phobos doesn't have those places of trying 
to dereference an array element, so I tried replacing format.d on 
my raspberry pi with the format.d I have on my laptop. This 
produced some other errors, which I won't bother posting yet.

What can I do to fix this and get the most recent version of 
phobos that will compile?

Johan <j j.nl> writes:

On Saturday, 8 August 2020 at 17:00:17 UTC, Jeremiah Glover wrote:
 I've been wanting to put together a programming to teach D. The 
 raspberry pi seemed like a good computer to use so everyone 
 could be guaranteed to have a computer to practice on. I've had 
 some trouble, however, getting a test project to compile, and 
 the first culprit lives in std.format.

 I tried both LDC and GDC by using `sudo apt install ldc` and 
 `sudo apt install gdc`

 compiling my test file with ldc gives these errors

 /usr/lib/ldc/arm-linux-gnueabihf/include/d/std/format.d(620): 
 Error: can only * a pointer, not a 'int'

 You can find my test file and a text file that makes the 
 program work at https://github.com/d-us-vb/diceware.

Seems to work fine with LDC 1.22:
https://d.godbolt.org/z/c14b1E

Perhaps the version of LDC and GDC that you are using is very old?

-Johan

Steven Schveighoffer <schveiguy gmail.com> writes:

On 8/8/20 1:00 PM, Jeremiah Glover wrote:

 What can I do to fix this and get the most recent version of phobos that 
 will compile?

You are using an old version of the compiler. formattedRead used to 
accept only pointers, not by ref.

See https://github.com/dlang/phobos/pull/5009

Try doing:
formattedRead(line, "%d\t%s", &dummy, &word);

Figure out which version of the compiler you have, and then use the docs 
for that version by downloading the compiler and using the local html 
documentation.

Alternatively, see if you can find a newer compiler that suports ARM.

-Steve