Hi All,

 I am a newbie for D programming and need some help, I am trying to write a program using the example given in the book The "D Programming Language" written by "Andrei Alexandrescu" with few changes such as the example program read the input from stdin and prints the data to stdout, but my program reads the input from the file(readfile.txt) and writes the output to another file(writefile.txt), and I am getting the below errors while compiling

Error:

[root@localhost DProjects]# dmd readwriteb.d
readwriteb.d(7): Error: cannot implicitly convert expression (__aggr2859.front()) of type ubyte[] to immutable(ubyte)[]
readwriteb.d(15): Error: cannot implicitly convert expression (receiveOnly()) of type immutable(ubyte)[] to std.outbuffer.OutBuffer
[root@localhost DProjects]#

Version: DMD64 D Compiler v2.071.0

Code:

import std.algorithm, std.concurrency, std.stdio, std.outbuffer, std.file;

void main() {
   enum bufferSize = 1024 * 100;
   auto file = File("readfile.txt", "r");
   auto tid = spawn(&fileWriter);
   foreach (immutable(ubyte)[] buffer; file.byChunk(bufferSize)) {
      send(tid, buffer);
   }
}

void fileWriter() {
   auto wbuf  = new OutBuffer();
   for (;;) {
      wbuf = receiveOnly!(immutable(ubyte)[])();
      write("writefile.txt", wbuf);
   }
}

From,
Vino.B

On Monday, 2 May 2016 at 16:39:13 UTC, vino wrote:
> Hi All,
>
>  I am a newbie for D programming and need some help, I am trying to write a program using the example given in the book The "D Programming Language" written by "Andrei Alexandrescu" with few changes such as the example program read the input from stdin and prints the data to stdout, but my program reads the input from the file(readfile.txt) and writes the output to another file(writefile.txt), and I am getting the below errors while compiling
>
> Error:
>
> [root@localhost DProjects]# dmd readwriteb.d
> readwriteb.d(7): Error: cannot implicitly convert expression (__aggr2859.front()) of type ubyte[] to immutable(ubyte)[]
> readwriteb.d(15): Error: cannot implicitly convert expression (receiveOnly()) of type immutable(ubyte)[] to std.outbuffer.OutBuffer
> [root@localhost DProjects]#
>
> Version: DMD64 D Compiler v2.071.0
>
> Code:
>
> import std.algorithm, std.concurrency, std.stdio, std.outbuffer, std.file;
>
> void main() {
>    enum bufferSize = 1024 * 100;
>    auto file = File("readfile.txt", "r");
>    auto tid = spawn(&fileWriter);
>    foreach (immutable(ubyte)[] buffer; file.byChunk(bufferSize)) {
>       send(tid, buffer);
>    }
> }
>
> void fileWriter() {
>    auto wbuf  = new OutBuffer();
>    for (;;) {
>       wbuf = receiveOnly!(immutable(ubyte)[])();
>       write("writefile.txt", wbuf);
>    }
> }
>
> From,
> Vino.B

File.byChunks iirc returns a mutable ubyte[] range, not an immutable(ubyte)[]. The easiest way to fix this would be to change the foreach variable to ubyte[] and make an immutable duplicate of it when sending via idup.

wbuf is inferred to be an OutBuffer but then you assign an immutable(ubyte)[] to it in your foreach loop; a type error.

On Monday, 2 May 2016 at 16:39:13 UTC, vino wrote:
> Hi All,
>
>  I am a newbie for D programming and need some help, I am trying to write a program using the example given in the book The "D Programming Language" written by "Andrei Alexandrescu"

Make sure to check the errata on his site: http://erdani.com/index.php?cID=109

> Page: 406 Print: 1
> Current text:
>     foreach (immutable(ubyte)[] buffer; stdin.byChunk(bufferSize)) send(tid, buffer);
> Correction:
>     foreach (buffer; stdin.byChunk(bufferSize)) send(tid, buffer.idup)