• John Chapman (11/11) Oct 22 2018 Given a function that returns a count of items, and another
• =?UTF-8?Q?Ali_=c3=87ehreli?= (23/36) Oct 22 2018 iota and map:
• John Chapman (3/4) Oct 22 2018 Thank you. And the funny thing is I used iota earlier today but

John Chapman <johnch_atms hotmail.com> writes:

Given a function that returns a count of items, and another 
function that returns an item at an index, is there anything 
built into Phobos that can use them together to build a range?

The two functions are from an external API, eg:

   int getFontCount();
   Item getItemAt(int index);

I was wondering if there was something like a "rangeOf" as 
illustrated:

   foreach (item; rangeOf!(() => getFontCount(), (i) => 
getItemAt(i)) {
   }

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 10/22/2018 03:51 PM, John Chapman wrote:
 Given a function that returns a count of items, and another function 
 that returns an item at an index, is there anything built into Phobos 
 that can use them together to build a range?
 
 The two functions are from an external API, eg:
 
    int getFontCount();
    Item getItemAt(int index);
 
 I was wondering if there was something like a "rangeOf" as illustrated:
 
    foreach (item; rangeOf!(() => getFontCount(), (i) => getItemAt(i)) {
    }

iota and map:

alias Item = string;

Item[] items = [ "Good font", "Better font" ];

int getFontCount() {
     import std.conv : to;
     return items.length.to!int;
}

Item getItemAt(int index) {
     return items[index];
}

auto allFonts() {
}

auto itemRange() {
     import std.range : iota;
     import std.algorithm : map;
     return iota(getFontCount()).map!(i => getItemAt(i));
}

void main() {
     import std.stdio;
     writeln(itemRange());
}

Ali

John Chapman <johnch_atms hotmail.com> writes:

On Monday, 22 October 2018 at 23:02:35 UTC, Ali Çehreli wrote:
 iota and map:

Thank you. And the funny thing is I used iota earlier today but 
it didn't occur to me for this!