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use std::result::Result as StdResult;
use error::*;
use lua::*;
/// Result is convertible to `MultiValue` following the common lua idiom of returning the result
/// on success, or in the case of an error, returning nil followed by the error
impl<'lua, T: ToLua<'lua>, E: ToLua<'lua>> ToLuaMulti<'lua> for StdResult<T, E> {
fn to_lua_multi(self, lua: &'lua Lua) -> Result<MultiValue<'lua>> {
let mut result = MultiValue::new();
match self {
Ok(v) => result.push_back(v.to_lua(lua)?),
Err(e) => {
result.push_back(Nil);
result.push_back(e.to_lua(lua)?);
}
}
Ok(result)
}
}
impl<'lua, T: ToLua<'lua>> ToLuaMulti<'lua> for T {
fn to_lua_multi(self, lua: &'lua Lua) -> Result<MultiValue<'lua>> {
let mut v = MultiValue::new();
v.push_back(self.to_lua(lua)?);
Ok(v)
}
}
impl<'lua, T: FromLua<'lua>> FromLuaMulti<'lua> for T {
fn from_lua_multi(mut values: MultiValue<'lua>, lua: &'lua Lua) -> Result<Self> {
Ok(T::from_lua(values.pop_front().unwrap_or(Nil), lua)?)
}
}
impl<'lua> ToLuaMulti<'lua> for MultiValue<'lua> {
fn to_lua_multi(self, _: &'lua Lua) -> Result<MultiValue<'lua>> {
Ok(self)
}
}
impl<'lua> FromLuaMulti<'lua> for MultiValue<'lua> {
fn from_lua_multi(values: MultiValue<'lua>, _: &'lua Lua) -> Result<Self> {
Ok(values)
}
}
/// Can be used to pass variadic values to or receive variadic values from Lua, where the type of
/// the values is all the same and the number of values is defined at runtime. This can be included
/// in an hlist when unpacking, but must be the final entry, and will consume the rest of the
/// parameters given.
pub struct Variadic<T>(pub Vec<T>);
impl<'lua, T: ToLua<'lua>> ToLuaMulti<'lua> for Variadic<T> {
fn to_lua_multi(self, lua: &'lua Lua) -> Result<MultiValue<'lua>> {
self.0.into_iter().map(|e| e.to_lua(lua)).collect()
}
}
impl<'lua, T: FromLua<'lua>> FromLuaMulti<'lua> for Variadic<T> {
fn from_lua_multi(values: MultiValue<'lua>, lua: &'lua Lua) -> Result<Self> {
values
.into_iter()
.map(|e| T::from_lua(e, lua))
.collect::<Result<Vec<T>>>()
.map(Variadic)
}
}
macro_rules! impl_tuple {
() => (
impl<'lua> ToLuaMulti<'lua> for () {
fn to_lua_multi(self, _: &'lua Lua) -> Result<MultiValue> {
Ok(MultiValue::new())
}
}
impl<'lua> FromLuaMulti<'lua> for () {
fn from_lua_multi(_: MultiValue, _: &'lua Lua) -> Result<Self> {
Ok(())
}
}
);
($last:ident $($name:ident)*) => (
impl<'lua, $($name,)* $last> ToLuaMulti<'lua> for ($($name,)* $last,)
where $($name: ToLua<'lua>,)*
$last: ToLuaMulti<'lua>
{
#[allow(unused_mut)]
#[allow(non_snake_case)]
fn to_lua_multi(self, lua: &'lua Lua) -> Result<MultiValue<'lua>> {
let ($($name,)* $last,) = self;
let mut results = $last.to_lua_multi(lua)?;
push_reverse!(results, $($name.to_lua(lua)?,)*);
Ok(results)
}
}
impl<'lua, $($name,)* $last> FromLuaMulti<'lua> for ($($name,)* $last,)
where $($name: FromLua<'lua>,)*
$last: FromLuaMulti<'lua>
{
#[allow(unused_mut)]
#[allow(non_snake_case)]
fn from_lua_multi(mut values: MultiValue<'lua>, lua: &'lua Lua) -> Result<Self> {
$(let $name = values.pop_front().unwrap_or(Nil);)*
let $last = FromLuaMulti::from_lua_multi(values, lua)?;
Ok(($(FromLua::from_lua($name, lua)?,)* $last,))
}
}
);
}
macro_rules! push_reverse {
($multi_value:expr, $first:expr, $($rest:expr,)*) => (
push_reverse!($multi_value, $($rest,)*);
$multi_value.push_front($first);
);
($multi_value:expr, $first:expr) => (
$multi_value.push_front($first);
);
($multi_value:expr,) => ();
}
impl_tuple! { }
impl_tuple! { A }
impl_tuple! { A B }
impl_tuple! { A B C }
impl_tuple! { A B C D }
impl_tuple! { A B C D E }
impl_tuple! { A B C D E F }
impl_tuple! { A B C D E F G }
impl_tuple! { A B C D E F G H }
impl_tuple! { A B C D E F G H I }
impl_tuple! { A B C D E F G H I J }
impl_tuple! { A B C D E F G H I J K }
impl_tuple! { A B C D E F G H I J K L }
impl_tuple! { A B C D E F G H I J K L M }
impl_tuple! { A B C D E F G H I J K L M N }
impl_tuple! { A B C D E F G H I J K L M N O }
impl_tuple! { A B C D E F G H I J K L M N O P }
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