# Zigler
Library test status:
## Installation
Zigler is [available in Hex](https://hex.pm/zigler), and the package can be installed
by adding `zigler` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:zigler, "~> 0.7.2", runtime: false}
]
end
```
## Documentation
Docs can be found at [https://hexdocs.pm/zigler](https://hexdocs.pm/zigler).
## Currently supported platforms
- Linux
- FreeBSD (tested, but not subjected to CI)
- MacOS (I believe it works but is still offically untested)
- Nerves cross-compilation is supported out of the box.
## Zig Nifs made easy
Wouldn't it be nice if you could make NIFs as easily as you can use the `asm`
keyword in C?
This is now possible, using the magic of Zig.
```elixir
defmodule ExampleZig do
use Zig
~Z"""
/// nif: example_fun/2
fn example_fun(value1: f64, value2: f64) bool {
return value1 > value2;
}
"""
end
test "example nifs" do
assert ExampleZig.example_fun(0.8, -0.8)
refute ExampleZig.example_fun(0.1, 0.4)
end
```
Zigler will do automatic type marshalling between Elixir code and Zig code.
It will also convert trickier types into types you care about, for example:
```elixir
defmodule ZigCollections do
use Zig
~Z"""
/// nif: string_count/1
fn string_count(string: []u8) i64 {
return @intCast(i64, string.len);
}
/// nif: list_sum/1
fn list_sum(array: []f64) f64 {
var sum: f64 = 0.0;
for(array) | item | {
sum += item;
}
return sum;
}
"""
end
test "type marshalling" do
assert 9 == ZigCollections.string_count("hello zig")
assert 6.0 == ZigCollections.list_sum([1.0, 2.0, 3.0])
end
```
Memory allocation with zigler is easy! A standard BEAM allocator is provided for you,
so any zig code you import will play nice with the BEAM.
```elixir
defmodule Allocations do
use Zig
~Z"""
/// nif: double_atom/1
fn double_atom(env: beam.env, string: []u8) beam.term {
var double_string = beam.allocator.alloc(u8, string.len * 2) catch {
return beam.raise_enomem(env);
};
defer beam.allocator.free(double_string);
for (string) | char, i | {
double_string[i] = char;
double_string[i + string.len] = char;
}
return beam.make_atom(env, double_string);
}
"""
end
test "allocations" do
assert :foofoo == Allocations.double_atom("foo")
end
```
It is a goal for Zigler to make using *it* to bind C libraries easier
than using C to bind C libraries. Here is an example:
```elixir
defmodule BlasDynamic do
use Zig,
libs: ["/usr/lib/x86_64-linux-gnu/blas/libblas.so"],
include: ["/usr/include/x86_64-linux-gnu"],
link_libc: true
~Z"""
const blas = @cImport({
@cInclude("cblas.h");
});
/// nif: blas_axpy/3
fn blas_axpy(env: beam.env, a: f64, x: []f64, y: []f64) beam.term {
if (x.len != y.len) {
return beam.raise_function_clause_error(env);
}
blas.cblas_daxpy(@intCast(c_int, x.len), a, x.ptr, 1, y.ptr, 1);
return beam.make_f64_list(env, y) catch {
return beam.raise_function_clause_error(env);
};
}
"""
end
test "we can use a blas shared library" do
# returns aX+Y
assert [11.0, 18.0] == BlasDynamic.blas_axpy(3.0, [2.0, 4.0], [5.0, 6.0])
end
```
### Documentation
You can document nif functions, local functions, zig structs, variables, and types.
If you document a nif function, it will be a part of the module documentation, and
accessible using the iex `h` method, etc.
Example:
```elixir
defmodule Documentation do
use Zig
~Z"""
/// a zero-arity function which returns 47.
/// nif: zero_arity/0
fn zero_arity() i64 {
return 47;
}
"""
end
```
## Zigler Principles
1. Make being a good citizen of the BEAM easy.
2. Use magic, but sparingly, only to prevent errors.
3. Let the user see behind the curtain.
4. Let the user opt out of magic.
5. Magic shouldn't get in the way.
