4 releases
0.3.0 | May 6, 2024 |
---|---|
0.2.0 |
|
0.1.2 | Mar 24, 2024 |
0.1.1 | Mar 23, 2024 |
0.1.0 | Mar 23, 2024 |
22 downloads per month
Used in attr-parser-fn
11KB
232 lines
Impl Variadic
A macro for generate variadic generics.
The syntax is similar to quote
.
Example
impl_variadics! {
..4 "T*" => {
impl<#(#T0),*> Display for TupleDisplay<(#(#T0,)*)>
where
#(#T0: Display,)*
{
fn fmt(&self, _f: &mut Formatter) -> Result {
#(self.0.#index.fmt(_f)?;)*
Ok(())
}
}
};
/*
10..20 "Ty*pe" "my_index_*" "and_more_*" => {
...
}
*/
}
it expands to
impl Display for TupleDisplay<()> {
fn fmt(&self, _f: &mut Formatter) -> Result {
Ok(())
}
}
impl<T0> Display for TupleDisplay<(T0,)>
where
T0: Display,
{
fn fmt(&self, _f: &mut Formatter) -> Result {
self.0 .0.fmt(_f)?;
Ok(())
}
}
impl<T0, T1> Display for TupleDisplay<(T0, T1)>
where
T0: Display,
T1: Display,
{
fn fmt(&self, _f: &mut Formatter) -> Result {
self.0 .0.fmt(_f)?;
self.0 .1.fmt(_f)?;
Ok(())
}
}
impl<T0, T1, T2> Display for TupleDisplay<(T0, T1, T2)>
where
T0: Display,
T1: Display,
T2: Display,
{
fn fmt(&self, _f: &mut Formatter) -> Result {
self.0 .0.fmt(_f)?;
self.0 .1.fmt(_f)?;
self.0 .2.fmt(_f)?;
Ok(())
}
}
- ..4: maximum iterator count is 4, from 0. you can add lower bound like
2..10
. "T*"
: a custom identifier pattern. will replace all*
with indexes. you can try other patterns like "Type" or "index_*".#index
: a builtin iterator gives 0 ~ max_index.#length
: a builtin integer equals to iterator length.#T0
: custom identifier. it givesT0
,T1
,T2
...TN
, where N is the
upper bound of the range minus 2. it coresponding to patternT*
, replace all*
with0
.
Dependencies
~1.5MB
~42K SLoC