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Fix last nits
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jroesch committed Aug 4, 2015
1 parent 2919e32 commit 471370a
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Showing 3 changed files with 54 additions and 49 deletions.
3 changes: 2 additions & 1 deletion src/libsyntax/ext/expand.rs
Expand Up @@ -1581,7 +1581,8 @@ pub fn expand_type(t: P<ast::Ty>, fld: &mut MacroExpander) -> P<ast::Ty> {
"type_macros",
t.span,
"type macros are experimental (see issue: #27336)");
t

DummyResult::raw_ty(t.span)
}
}
_ => t
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1 change: 1 addition & 0 deletions src/test/compile-fail/type-macros-fail.rs
Expand Up @@ -14,6 +14,7 @@ macro_rules! Id {

struct Foo<T> {
x: Id!(T)
//~^ ERROR: type macros are experimental (see issue: #27336)
}

fn main() {
Expand Down
99 changes: 51 additions & 48 deletions src/test/run-pass/type-macros-hlist.rs
Expand Up @@ -13,74 +13,77 @@
use std::ops::*;

#[derive(Copy, Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
struct Nil; // empty HList
struct Nil;
// empty HList
#[derive(Copy, Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
struct Cons<H, T: HList>(H, T); // cons cell of HList
struct Cons<H, T: HList>(H, T);
// cons cell of HList

// trait to classify valid HLists
trait HList {}
impl HList for Nil {}
impl<H, T: HList> HList for Cons<H, T> {}
// trait to classify valid HLists
trait HList { }
impl HList for Nil { }
impl <H, T: HList> HList for Cons<H, T> { }

// term-level macro for HLists
macro_rules! hlist {
{} => { Nil };
{ $head:expr } => { Cons($head, Nil) };
{ $head:expr, $($tail:expr),* } => { Cons($head, hlist!($($tail),*)) };
}
macro_rules! hlist({ } => { Nil } ; { $ head : expr } => {
Cons ( $ head , Nil ) } ; {
$ head : expr , $ ( $ tail : expr ) , * } => {
Cons ( $ head , hlist ! ( $ ( $ tail ) , * ) ) } ;);

// type-level macro for HLists
macro_rules! HList {
{} => { Nil };
{ $head:ty } => { Cons<$head, Nil> };
{ $head:ty, $($tail:ty),* } => { Cons<$head, HList!($($tail),*)> };
}
macro_rules! HList({ } => { Nil } ; { $ head : ty } => {
Cons < $ head , Nil > } ; {
$ head : ty , $ ( $ tail : ty ) , * } => {
Cons < $ head , HList ! ( $ ( $ tail ) , * ) > } ;);

// nil case for HList append
impl<Ys: HList> Add<Ys> for Nil {
type Output = Ys;
impl <Ys: HList> Add<Ys> for Nil {
type
Output
=
Ys;

fn add(self, rhs: Ys) -> Ys {
rhs
}
fn add(self, rhs: Ys) -> Ys { rhs }
}

// cons case for HList append
impl<Rec: HList + Sized, X, Xs: HList, Ys: HList> Add<Ys> for Cons<X, Xs> where
Xs: Add<Ys, Output = Rec>,
{
type Output = Cons<X, Rec>;
impl <Rec: HList + Sized, X, Xs: HList, Ys: HList> Add<Ys> for Cons<X, Xs>
where Xs: Add<Ys, Output = Rec> {
type
Output
=
Cons<X, Rec>;

fn add(self, rhs: Ys) -> Cons<X, Rec> {
Cons(self.0, self.1 + rhs)
}
fn add(self, rhs: Ys) -> Cons<X, Rec> { Cons(self.0, self.1 + rhs) }
}

// type macro Expr allows us to expand the + operator appropriately
macro_rules! Expr {
{ ( $($LHS:tt)+ ) } => { Expr!($($LHS)+) };
{ HList ! [ $($LHS:tt)* ] + $($RHS:tt)+ } => {
<Expr!(HList![$($LHS)*]) as Add<Expr!($($RHS)+)>>::Output
};
{ $LHS:tt + $($RHS:tt)+ } => { <Expr!($LHS) as Add<Expr!($($RHS)+)>>::Output };
{ $LHS:ty } => { $LHS };
}
macro_rules! Expr({ ( $ ( $ LHS : tt ) + ) } => { Expr ! ( $ ( $ LHS ) + ) } ;
{ HList ! [ $ ( $ LHS : tt ) * ] + $ ( $ RHS : tt ) + } => {
< Expr ! ( HList ! [ $ ( $ LHS ) * ] ) as Add < Expr ! (
$ ( $ RHS ) + ) >> :: Output } ; {
$ LHS : tt + $ ( $ RHS : tt ) + } => {
< Expr ! ( $ LHS ) as Add < Expr ! ( $ ( $ RHS ) + ) >> ::
Output } ; { $ LHS : ty } => { $ LHS } ;);

// test demonstrating term level `xs + ys` and type level `Expr!(Xs + Ys)`
fn main() {
fn aux<Xs: HList, Ys: HList>(xs: Xs, ys: Ys) -> Expr!(Xs + Ys)
where Xs: Add<Ys> {
xs + ys
}
fn aux<Xs: HList, Ys: HList>(xs: Xs, ys: Ys) -> Expr!(Xs + Ys) where
Xs: Add<Ys> {
xs + ys
}

let xs: HList![&str, bool, Vec<u64>] = hlist!["foo", false, vec![]];
let ys: HList![u64, [u8; 3], ()] = hlist![0, [0, 1, 2], ()];
let xs: HList!(& str , bool , Vec < u64 >) =
hlist!("foo" , false , vec ! [ ]);
let ys: HList!(u64 , [ u8 ; 3 ] , ( )) =
hlist!(0 , [ 0 , 1 , 2 ] , ( ));

// demonstrate recursive expansion of Expr!
let zs: Expr!((HList![&str] + HList![bool] + HList![Vec<u64>]) +
(HList![u64] + HList![[u8; 3], ()]) +
HList![])
= aux(xs, ys);
assert_eq!(zs, hlist!["foo", false, vec![], 0, [0, 1, 2], ()])
let zs:
Expr!((
HList ! [ & str ] + HList ! [ bool ] + HList ! [ Vec < u64 >
] ) + ( HList ! [ u64 ] + HList ! [ [ u8 ; 3 ] , ( ) ] ) +
HList ! [ ]) = aux(xs, ys);
assert_eq!(zs , hlist ! [
"foo" , false , vec ! [ ] , 0 , [ 0 , 1 , 2 ] , ( ) ])
}

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