www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - Passing a byLine as an argument to InputRange

reply Jeff <massung gmail.com> writes:
I have a class where I'd like to supply it with an 
InputRange!string. Yet, for the life of me I can't seem to pass 
to it a File.byLine, even though the documentation states it's an 
InputRange.

```
class Foo {
   private InputRange!string source;

   this(InputRange!string s) {
     source = s;
   }

   // do stuff with it
}

new Foo(File("stuff.txt").byLine);

// Error constructor Foo.this(InputRange!string) is not callable 
using argument types (ByLineImpl!(char, char))
```

I have to believe this is possible. I'm thinking maybe I need to 
template the constructor with something like:

```
this(R)(R s) if (isInputRange!R)
```

But, then I seem to have 2 problems:

1. I haven't ensured it's an InputRange!string
2. I've just punted the problem up a level, because my member 
variable doesn't work.

Any help appreciated. Thanks!
May 13 2021
next sibling parent Adam D. Ruppe <destructionator gmail.com> writes:
On Thursday, 13 May 2021 at 17:07:51 UTC, Jeff wrote:

 I have a class where I'd like to supply it with an 
 InputRange!string. Yet, for the life of me I can't seem to pass 
 to it a File.byLine, even though the documentation states it's 
 an InputRange.


byLine is not a range of string. It is a range of mutable char[].

I think byLineCopy yields strings though, try that. And if it 
doesn't work mabye `InputRange!(char[])` or similar might work.
May 13 2021
prev sibling parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 5/13/21 10:07 AM, Jeff wrote:


 I have a class where I'd like to supply it with an InputRange!string.
 Yet, for the life of me I can't seem to pass to it a File.byLine


As Adam said, your range elements need to be converted to string e.g. 
with 'text' (the same as to!string). However, you must also create a 
dynamic InputRange!string object for dynamic polymorphism that 
InputRange provides. And that's achieved by function inputRangeObject():

import std.range;
import std.stdio;
import std.algorithm;
import std.conv;

class Foo {
   private InputRange!string source;

   this(InputRange!string s) {
     source = s;
   }

   // do stuff with it
}

void main() {
   new Foo(inputRangeObject(File("stuff.txt").byLine.map!text));
}

Ali
May 13 2021
next sibling parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 5/13/21 11:29 AM, Ali =C3=87ehreli wrote:


 create a=20
 dynamic InputRange!string object for dynamic polymorphism that=20
 InputRange provides. And that's achieved by function inputRangeObject()=


:

Some examples:

=20
http://ddili.org/ders/d.en/ranges_more.html#ix_ranges_more.polymorphism,%=
20run-time

Ali
May 13 2021
parent Imperatorn <johan_forsberg_86 hotmail.com> writes:
On Thursday, 13 May 2021 at 18:31:41 UTC, Ali Çehreli wrote:

 On 5/13/21 11:29 AM, Ali Çehreli wrote:


 create a dynamic InputRange!string object for dynamic 
 polymorphism that InputRange provides. And that's achieved by 
 function inputRangeObject():


 Some examples:


 http://ddili.org/ders/d.en/ranges_more.html#ix_ranges_more.polymorphism,%20run-time

 Ali


This book has saved my life many times! ☀
May 13 2021
prev sibling parent Jeff <massung gmail.com> writes:
On Thursday, 13 May 2021 at 18:29:08 UTC, Ali Çehreli wrote:

 On 5/13/21 10:07 AM, Jeff wrote:


 I have a class where I'd like to supply it with an


 InputRange!string.

 Yet, for the life of me I can't seem to pass to it a


 File.byLine

 As Adam said, your range elements need to be converted to 
 string e.g. with 'text' (the same as to!string). However, you 
 must also create a dynamic InputRange!string object for dynamic 
 polymorphism that InputRange provides. And that's achieved by 
 function inputRangeObject():


Thank you all. I'm up and running. ;-)
May 13 2021