On 01/13/2017 04:29 PM, Dave Chapman wrote:
> When I use auto and print out the type of b it is something like
> args.main.FilterResult!(__lambda2, DirIterator).FilterResult and for the
> "if" version of
> b and args.main.FilterResult!(__lambda3, DirIterator).FilterResult for
> the "else" version
> so they are really different types.
The solution for that case is to use std.range.choose:
auto b = choose(some_condition,
all.filter!(f => baseName(f.name) == "file_name.txt"),
all.filter!(f => (f.name.endsWith(".d") )));
but I get the following error with DMD64 D Compiler v2.072.1:
Error: no property '__postblit' for type 'FilterResult!(__lambda2,
DirIterator)', did you mean '__xpostblit'?
So, I put .array after both expressions below.
The idiomatic way for what you're looking for is std.array.array (which
is also exposed through std.range):
import std.stdio;
import std.file;
import std.algorithm;
import std.range;
import std.path;
void main(string[] args) {
bool some_condition = (args.length > 1) && (args[1] == "foo");
auto all = dirEntries("directory", SpanMode.shallow);
auto b = choose(some_condition,
all.filter!(f => baseName(f.name) ==
"file_name.txt").array,
all.filter!(f => (f.name.endsWith(".d") )).array);
writeln(b);
}
However, in most cases keeping 'b' as a lazy algorithm is sufficient.
Unless you really need an array e.g. for sorting, you can use
std.algorithm.each (or map, etc.). (Not applicable in this case because
of the error I mentioned above.)
Ali
