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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:02:58 +0000
commit698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch)
tree173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/issues/issue-29746.rs
parentInitial commit. (diff)
downloadrustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz
rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/issues/issue-29746.rs')
-rw-r--r--src/test/ui/issues/issue-29746.rs36
1 files changed, 36 insertions, 0 deletions
diff --git a/src/test/ui/issues/issue-29746.rs b/src/test/ui/issues/issue-29746.rs
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+++ b/src/test/ui/issues/issue-29746.rs
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+// run-pass
+// zip!(a1,a2,a3,a4) is equivalent to:
+// a1.zip(a2).zip(a3).zip(a4).map(|(((x1,x2),x3),x4)| (x1,x2,x3,x4))
+macro_rules! zip {
+ // Entry point
+ ([$a:expr, $b:expr, $($rest:expr),*]) => {
+ zip!([$($rest),*], $a.zip($b), (x,y), [x,y])
+ };
+
+ // Intermediate steps to build the zipped expression, the match pattern, and
+ // and the output tuple of the closure, using macro hygiene to repeatedly
+ // introduce new variables named 'x'.
+ ([$a:expr, $($rest:expr),*], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
+ zip!([$($rest),*], $zip.zip($a), ($pat,x), [$($flat),*, x])
+ };
+
+ // Final step
+ ([], $zip:expr, $pat:pat, [$($flat:expr),+]) => {
+ $zip.map(|$pat| ($($flat),+))
+ };
+
+ // Comma
+ ([$a:expr], $zip:expr, $pat:pat, [$($flat:expr),*]) => {
+ zip!([$a,], $zip, $pat, [$($flat),*])
+ };
+}
+
+fn main() {
+ let p1 = vec![1i32, 2].into_iter();
+ let p2 = vec!["10", "20"].into_iter();
+ let p3 = vec![100u16, 200].into_iter();
+ let p4 = vec![1000i64, 2000].into_iter();
+
+ let e = zip!([p1,p2,p3,p4]).collect::<Vec<_>>();
+ assert_eq!(e[0], (1i32,"10",100u16,1000i64));
+}