digitalmars.D.learn - How to automatically generate function overloads
I'm porting over my linear algebra library from C++, and I have a
bunch of functions that work on both scalars and vectors. The
vector versions just apply the scalar function to every element
of the vector, for example:
```D
float clamp01(float x) { return x < 0 ? 0 : (x > 1 ? 1 : x); }
float[N] clamp01(size_t N)(float[N] vec)
{
float[N] result;
static foreach (i; 0 .. N)
result[i] = clamp01(vec[i]);
return result;
}
```
And this is great, I don't have to write the same function for
different array lengths.
But I still have like 30-ish of these functions and I would like
to generate the array overload automatically from the scalar
overload.
So I would like something like a mixin, that I can use like this:
```D
mixin Vectorize_Unary_Function!clamp01; // Generates the code
above.
mixin Vectorize_Unary_Function!floor;
mixin Vectorize_Unary_Function!ceil;
...
```
It doesn't have to be a mixin like this. I don't really care what
it is as long as it works :)
How could I do this?
May 04 2021
On Tuesday, 4 May 2021 at 11:00:42 UTC, Blatnik wrote:How could I do this?I've already tried this: ```D mixin template Vectorize_Unary_Function(alias Function) { float[N] Function(size_t N)(float[N] vec) { float[N] result; static foreach (i; 0 .. N) result[i] = Function(vec[i]); return result; } } ``` But it didn't work. ```D mixin Vectorize_Unary_Function!clamp01; float[2] vec = [1, 2]; float[2] clamped = clamp01(vec); // Error ``` I think it actually declared a function called "Function" instead of calling it "clamp01" like the alias I passed in.
May 04 2021
On Tuesday, 4 May 2021 at 11:00:42 UTC, Blatnik wrote:
I'm porting over my linear algebra library from C++, and I have
a bunch of functions that work on both scalars and vectors. The
vector versions just apply the scalar function to every element
of the vector, for example:
```D
float clamp01(float x) { return x < 0 ? 0 : (x > 1 ? 1 : x); }
float[N] clamp01(size_t N)(float[N] vec)
{
float[N] result;
static foreach (i; 0 .. N)
result[i] = clamp01(vec[i]);
return result;
}
```
And this is great, I don't have to write the same function for
different array lengths.
But I still have like 30-ish of these functions and I would
like to generate the array overload automatically from the
scalar overload.
So I would like something like a mixin, that I can use like
this:
```D
mixin Vectorize_Unary_Function!clamp01; // Generates the code
above.
mixin Vectorize_Unary_Function!floor;
mixin Vectorize_Unary_Function!ceil;
...
```
It doesn't have to be a mixin like this. I don't really care
what it is as long as it works :)
How could I do this?
```D
float clamp01(float x) { return x < 0 ? 0 : (x > 1 ? 1 : x); }
template Vectorize_Unary_Function(alias fun) {
float[N] Vectorize_Unary_Function(size_t N)(float[N] vec)
{
float[N] result;
static foreach (i; 0 .. N)
result[i] = fun(vec[i]);
return result;
}
}
alias clamp01 = Vectorize_Unary_Function!clamp01;
void main() {
float[5] vec = [1,2,3,4,5];
float[5] other = clamp01(vec);
writeln(vec);
writeln(other);
}
```
Not exactly what you were asking for but I hope it works, tricky
part is I'm not sure how to generate the function name without
string mixins so that's why I used alias instead.
May 04 2021
On Tuesday, 4 May 2021 at 11:21:20 UTC, Zone wrote:
```D
template Vectorize_Unary_Function(alias fun) {
float[N] Vectorize_Unary_Function(size_t N)(float[N] vec)
{
float[N] result;
static foreach (i; 0 .. N)
result[i] = fun(vec[i]);
return result;
}
}
alias clamp01 = Vectorize_Unary_Function!clamp01;
```
Not exactly what you were asking for but I hope it works,
tricky part is I'm not sure how to generate the function name
without string mixins so that's why I used alias instead.
Awesome, this does exactly what I wanted. Thanks for the help! :)
May 04 2021









Blatnik <blatblatnik gmail.com> 