std.csv.csvReader operating on File.byLine()

[Rene Zwanenburg]

Ah yes, I understand. Thanks.

For the sake of cleanliness (and Walter's article on component 
programming ;) ), is there a way to treat a file as an InputRange 
of characters? I think this is quite a common use case.

On Sunday, 7 October 2012 at 19:32:12 UTC, Ali Çehreli wrote:
> On 10/07/2012 11:21 AM, Rene Zwanenburg wrote:
> > Hi,
> >
> > To my understanding, The csv reader in std.csv is able to
> operate on any
> > kind of input range.
>
> The error message took me to the definition of the function. 
> The template constraints require that the element type of the 
> range must be a dchar:
>
> // ...
>   if(isInputRange!Range && is(ElementType!Range == dchar)
> // ...
>
> In your case, the element type of byLine() is a string. (I 
> think.)
>
> > However I can only get it to work on strings.
> > Please take a look at the following line of code. Did I make
> some mistake?
> >
> > auto reader = csvReader!(Tuple!(int, int,
> float))(someFile.byLine());
> >
> > When I try to compile that, the compiler output is:
> >
> > main.d(24): Error: template std.csv.csvReader does not match
> any
> > function template declaration
> > C:\D\dmd2\windows\bin\..\..\src\phobos\std\csv.d(283): Error:
> template
> > std.csv.csvReader cannot deduce template function from
> argument types
> > !(Tuple!(int,int,float))(ByLine!(char,char))
> > main.d(24): Error: template instance
> csvReader!(Tuple!(int,int,float))
> > errors instantiating template
> >
> > As a workaround I could use readText, but that's dirty and
> won't work
> > for large csv files.
>
> If deneme.txt contains this:
>
> 1,2,3.5
> 6,7,8.5
>
> This works:
>
> import std.stdio;
> import std.csv;
> import std.typecons;
>
> void main()
> {
>     auto someFile = File("deneme.txt");
>
>     foreach (line; someFile.byLine()) {
>         auto reader = csvReader!(Tuple!(int, int, float))(line);
>         foreach (record; reader) {
>             writeln(record);
>         }
>     }
> }
>
> Ali