ocaml 0.14.0

OCaml bindings for Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141

/// `local!` can used to define local variables in OCaml functions
#[macro_export]
macro_rules! local {
    ($($local:ident),*) => {
        #[allow(unused_mut)]
        $(let mut $local = $crate::Value($crate::sys::UNIT);)*
        #[allow(unused_unsafe)]
        $crate::sys::caml_param!($($local.0),*);
    }
}

/// `frame!` can be used to create new local variables that play nicely with the garbage collector
#[macro_export]
macro_rules! frame {
    (($($param:ident),*) $code:block) => {
       {
            #[allow(unused_unsafe)]
            let caml_frame = unsafe { $crate::sys::local_roots() };
            $crate::local!($($param),*);
            #[allow(unused_mut)]
            let mut res = || { $code };
            let res = res();

            #[allow(unused_unsafe)]
            unsafe { $crate::sys::set_local_roots(caml_frame) };
            res
        }
    }
}

/// `body!` is needed to help the OCaml runtime to manage garbage collection, it should
/// be used to wrap the body of each function exported to OCaml.
///
/// ```rust
/// #[no_mangle]
/// pub extern "C" fn example(a: ocaml::Value, b: ocaml::Value) -> ocaml::Value {
///     ocaml::body!((a, b) {
///         let a = a.int_val();
///         let b = b.int_val();
///         ocaml::Value::int(a + b)
///     })
/// }
/// ```
#[macro_export]
#[cfg(feature = "no-std")]
macro_rules! body {
    ($(($($param:expr),*))? $code:block) => {
        $crate::sys::caml_body!($(($($param.0),*))? $code);
    }
}

#[cfg(not(feature = "no-std"))]
static PANIC_HANDLER_INIT: std::sync::atomic::AtomicBool =
    std::sync::atomic::AtomicBool::new(false);

#[cfg(not(feature = "no-std"))]
#[doc(hidden)]
pub fn init_panic_handler() {
    if PANIC_HANDLER_INIT.compare_and_swap(false, true, std::sync::atomic::Ordering::Relaxed) {
        return;
    }

    ::std::panic::set_hook(Box::new(|info| {
        let err = info.payload();
        let msg = if err.is::<&str>() {
            err.downcast_ref::<&str>().unwrap()
        } else if err.is::<String>() {
            err.downcast_ref::<String>().unwrap().as_ref()
        } else {
            "rust panic"
        };

        if let Some(err) = crate::Value::named("Rust_exception") {
            crate::Error::raise_value(err, msg);
        }

        crate::Error::raise_failure(msg)
    }))
}

/// `body!` is needed to help the OCaml runtime to manage garbage collection, it should
/// be used to wrap the body of each function exported to OCaml. Panics from Rust code
/// will automatically be unwound/caught here (unless the `no-std` feature is enabled)
///
/// ```rust
/// #[no_mangle]
/// pub extern "C" fn example(a: ocaml::Value, b: ocaml::Value) -> ocaml::Value {
///     ocaml::body!((a, b) {
///         let a = a.int_val();
///         let b = b.int_val();
///         ocaml::Value::int(a + b)
///     })
/// }
/// ```
#[macro_export]
#[cfg(not(feature = "no-std"))]
macro_rules! body {
    ($(($($param:expr),*))? $code:block) => {{
        // Ensure panic handler is initialized
        $crate::init_panic_handler();

        // Initialize OCaml frame
        #[allow(unused_unsafe)]
        let caml_frame = unsafe { $crate::sys::local_roots() };

        // Initialize parameters
        $(
            $crate::sys::caml_param!($($param.0),*);
        )?

        // Execute Rust function
        #[allow(unused_mut)]
        let mut res = || {$code };
        let res = res();

        #[allow(unused_unsafe)]
        unsafe { $crate::sys::set_local_roots(caml_frame) };

        res
    }}
}

#[macro_export]
/// Convenience macro to create an OCaml array
macro_rules! array {
    ($($x:expr),*) => {{
        $crate::ToValue::to_value(&vec![$($crate::ToValue::to_value(&$x)),*])
    }}
}

#[macro_export]
/// Convenience macro to create an OCaml list
macro_rules! list {
    ($($x:expr),*) => {{
        let mut l = $crate::list::empty();
        for i in (&[$($x),*]).into_iter().rev() {
            $crate::list::push_hd(&mut l, $crate::ToValue::to_value(i));
        }
        l
    }};
}