Re: How to get type returned by e.g. std.algorithm.iteration.filter
Last version using more from the outer template
#!/usr/bin/env rdmd
import std.stdio;
import std.algorithm;
import std.typecons;
import std.array;
import std.range;
import std.traits;
auto byMinimum(Ranges)(Ranges ranges)
{
auto getNonEmpty()
{
return ranges.filter!("!a.empty");
}
auto nonEmpty = getNonEmpty;
auto minimumOfRanges()
{
// dfmt off
return nonEmpty
.map!(range => tuple!("range", "line")(range, range.front))
.minElement!("a.line");
// dfmt on
}
ReturnType!(minimumOfRanges) minRangeAndLine;
struct ByMinimum
{
bool empty()
{
return nonEmpty.empty;
}
auto front()
{
minRangeAndLine = minimumOfRanges;
return minRangeAndLine;
}
void popFront()
{
nonEmpty = getNonEmpty;
minRangeAndLine.range.popFront;
}
}
return ByMinimum();
}
void main(string[] files)
{
foreach (n; files[1 .. $].map!(name =>
File(name).byLine(No.keepTerminator)).array.byMinimum)
{
writeln(n.line);
}
}
Re: How to get type returned by e.g. std.algorithm.iteration.filter
On 19.05.19 20:38, Jacob Carlborg wrote:
On 2019-05-19 15:36, Christian Köstlin wrote:
Unfortunately I have no idea how to even store the result of this
search in an attribute of ByMinimum, as I cannot writeout its type.
In general you can use `typeof()`, where `` is
the expression you want to get the type of.
Thanks for the hint. The best I could come up with this is:
#!/usr/bin/env rdmd
import std.stdio;
import std.algorithm;
import std.typecons;
import std.array;
import std.range;
import std.traits;
auto byMinimum(Ranges)(Ranges ranges)
{
auto getNonEmpty()
{
return ranges.filter!("!a.empty");
}
auto minimumOfRanges(Ranges)(Ranges ranges) {
// dfmt off
return ranges
.map!(range => tuple!("range", "line")(range, range.front))
.minElement!("a.line");
// dfmt on
}
auto nonEmpty = getNonEmpty;
ReturnType!(minimumOfRanges!(typeof(nonEmpty))) minRangeAndLine;
struct ByMinimum(Ranges)
{
bool empty()
{
return nonEmpty.empty;
}
auto front()
{
minRangeAndLine = minimumOfRanges(nonEmpty);
return minRangeAndLine;
}
void popFront()
{
minRangeAndLine.range.popFront;
nonEmpty = getNonEmpty;
}
}
return ByMinimum!(Ranges)();
}
void main(string[] files)
{
foreach (n; files[1 .. $].map!(name =>
File(name).byLine(No.keepTerminator)).array.byMinimum)
{
writeln(n.line);
}
}
Still it looks a little clumsy. Any ideas?
--
Christian
Re: How to get type returned by e.g. std.algorithm.iteration.filter
On 2019-05-19 15:36, Christian Köstlin wrote: Unfortunately I have no idea how to even store the result of this search in an attribute of ByMinimum, as I cannot writeout its type. In general you can use `typeof()`, where `` is the expression you want to get the type of. -- /Jacob Carlborg
How to get type returned by e.g. std.algorithm.iteration.filter
I would like to join several sorted files into one big sorted file.
For that I came up with this snippet:
#!/usr/bin/env rdmd
import std.stdio;
import std.algorithm;
import std.typecons;
import std.array;
import std.range;
auto byMinimum(Ranges)(Ranges ranges)
{
auto getNonEmpty()
{
return ranges.filter!("!a.empty");
}
auto nonEmpty = getNonEmpty;
struct ByMinimum(Ranges)
{
bool empty()
{
return nonEmpty.empty;
}
auto front()
{
auto minRangeAndLine = nonEmpty.map!(range => tuple!("range",
"line")(range, range.front)).minElement!("a.line");
return minRangeAndLine;
}
void popFront()
{
auto minRangeAndLine = nonEmpty.map!(range => tuple!("range",
"line")(range, range.front)).minElement!("a.line");
minRangeAndLine.range.popFront;
nonEmpty = getNonEmpty;
}
}
return ByMinimum!(Ranges)();
}
void main(string[] files)
{
foreach (n; files[1 .. $].map!(name =>
File(name).byLine(No.keepTerminator)).array.byMinimum)
{
writeln(n.line);
}
}
I would like to get rid of the duplication that searches for the range
with the next minimum in terms of runtime but also in terms of code
written out. Unfortunately I have no idea how to even store the result
of this search in an attribute of ByMinimum, as I cannot writeout its type.
Kind regards,
Christian
