• StupidIsAsStupidDoes (22/22) Oct 31 2012 There may be a better way to solve this but I'm trying to learn
• bearophile (17/18) Oct 31 2012 Such internal errors are compiler bugs that should be added to
• Ellery Newcomer (13/16) Oct 31 2012 On a recent dmd build from github, I don't get any ICE, so it may have

"StupidIsAsStupidDoes" <kc_heaser yahoo.com> writes:

There may be a better way to solve this but I'm trying to learn 
Phobos and parameter typing and anonymous function, etc.  So this 
is probably more of an academic question but I've got the 
following code:

int countBetween(T)(T[] x, T low, T high)
{
    auto k = count!( (x){return ((x >= low) && (x <= high));} ) 
(x);
    return k;
}

int[] a = [ 9, 77, 1, 13, 76, 17, 4, 27, 99, 5 ];

auto m = countBetween!(int)(a, 1, 25);      // works!


char[] b = ['h', 'e', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd'];
	
auto n = countBetween!(char)(b, 'c', 'k');  // fails



The integer call compiles and runs correctly.

The char call doesn't compile and I get a toir.c internal error.


The library definition says count is
size_t count(alias pred = "true", Range)(Range r);


I'm still trying to get my head around Ranges. Is a int array a 
valid range but a character array not?

Any enlightenment is welcome.

"bearophile" <bearophileHUGS lycos.com> writes:

StupidIsAsStupidDoes:

 The char call doesn't compile and I get a toir.c internal error.

Such internal errors are compiler bugs that should be added to 
Bugzilla.

But I have compiled the following program with the latest DMD 
GIT-head 32 bit Windows, and I see no compiler bugs:


import std.algorithm: count;

int countBetween(T)(T[] x, T low, T high) {
     return x.count!(x => x >= low && x <= high)();
}

void main() {
     int[] a = [9, 77, 1, 13, 76, 17, 4, 27, 99, 5];
     auto m = countBetween(a, 1, 25);

     char[] b = ['h', 'e', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd'];
     auto n = countBetween(b, 'c', 'k');
}

Bye,
bearophile

Ellery Newcomer <ellery-newcomer utulsa.edu> writes:

On 10/31/2012 04:35 PM, StupidIsAsStupidDoes wrote:
 The char call doesn't compile and I get a toir.c internal error.

On a recent dmd  build from github, I don't get any ICE, so it may have 
been fixed. I do get some disconcerting type deduction failures, though...

 I'm still trying to get my head around Ranges. Is a int array a valid
 range but a character array not?

All arrays are valid ranges, but char[], wchar[], and const variations 
thereof are special. They are treated as ranges of dchar so that you are 
guaranteed to get complete unicode characters out of them.

your code, modified:

import std.traits;

size_t countBetween(Range)(Range arr, ElementType!Range low, 
ElementType!Range high) {
     return count!( (x){return ((x >= low) && (x <= high)); })(arr);
}

ought to handle both int[] and char[] properly.