diff options
Diffstat (limited to 'vendor/time/src/shim.rs')
| -rw-r--r-- | vendor/time/src/shim.rs | 180 |
1 files changed, 0 insertions, 180 deletions
diff --git a/vendor/time/src/shim.rs b/vendor/time/src/shim.rs deleted file mode 100644 index b9ac97a16..000000000 --- a/vendor/time/src/shim.rs +++ /dev/null @@ -1,180 +0,0 @@ -//! Macro for simulating let-else on older compilers. -//! -//! This module and its macros will be removed once the MSRV is 1.65 (NET 2023-05-03). - -#![allow(unused_macros)] -#![allow(clippy::missing_docs_in_private_items)] - -// The following code is copyright 2016 Alex Burka. Available under the MIT OR Apache-2.0 license. -// Some adaptations have been made to the original code. - -pub(crate) enum LetElseBodyMustDiverge {} - -#[allow(clippy::missing_docs_in_private_items)] -macro_rules! __guard_output { - ((($($imms:ident)*) ($($muts:ident)*)), - [($($pattern:tt)*) ($rhs:expr) ($diverge:expr)]) => { - __guard_impl!(@as_stmt - let ($($imms,)* $(mut $muts,)*) = { - #[allow(unused_mut)] - match $rhs { - $($pattern)* => { - ($($imms,)* $($muts,)*) - }, - _ => { - let _: $crate::shim::LetElseBodyMustDiverge = $diverge; - }, - } - } - ) - }; -} - -macro_rules! __guard_impl { - // 0. cast a series of token trees to a statement - (@as_stmt $s:stmt) => { $s }; - - // 1. output stage - (@collect () -> $($rest:tt)*) => { - __guard_output!($($rest)*) - }; - - - // 2. identifier collection stage - // The pattern is scanned destructively. Anything that looks like a capture (including - // false positives, like un-namespaced/empty structs or enum variants) is copied into the - // appropriate identifier list. Irrelevant symbols are discarded. The scanning descends - // recursively into bracketed structures. - - // unwrap brackets and prepend their contents to the pattern remainder, in case there are captures inside - (@collect (($($inside:tt)*) $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru) - }; - (@collect ({$($inside:tt)*} $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru) - }; - (@collect ([$($inside:tt)*] $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru) - }; - - // discard irrelevant symbols - (@collect (, $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - (@collect (.. $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - (@collect (@ $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - (@collect (_ $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - (@collect (& $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - - // ignore generic parameters - (@collect (:: <$($generic:tt),*> $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - // a path can't be a capture, and a path can't end with ::, so the ident after :: is never a capture - (@collect (:: $pathend:ident $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - - // alternative patterns may be given with | as long as the same captures (including type) appear on each side - // due to this property, if we see a | we've already parsed all the captures and can simply stop - (@collect (| $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect () -> $idents, $thru) // discard the rest of the pattern, proceed to output stage - }; - - // throw away some identifiers that do not represent captures - - // an ident followed by a colon is the name of a structure member - (@collect ($id:ident: $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - // paths do not represent captures - (@collect ($pathcomp:ident :: $pathend:ident $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> $idents, $thru) - }; - // an ident followed by parentheses is the name of a tuple-like struct or enum variant - // (unwrap the parens to parse the contents) - (@collect ($id:ident ($($inside:tt)*) $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru) - }; - // an ident followed by curly braces is the name of a struct or struct-like enum variant - // (unwrap the braces to parse the contents) - (@collect ($id:ident {$($inside:tt)*} $($tail:tt)*) -> $idents:tt, $thru:tt) => { - __guard_impl!(@collect ($($inside)* $($tail)*) -> $idents, $thru) - }; - - // actually identifier collection happens here! - - // capture by mutable reference! - (@collect (ref mut $id:ident $($tail:tt)*) -> (($($imms:ident)*) $muts:tt), $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> (($($imms)* $id) $muts), $thru) - }; - // capture by immutable reference! - (@collect (ref $id:ident $($tail:tt)*) -> (($($imms:ident)*) $muts:tt), $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> (($($imms)* $id) $muts), $thru) - }; - // capture by move into mutable binding! - (@collect (mut $id:ident $($tail:tt)*) -> ($imms:tt ($($muts:ident)*)), $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> ($imms ($($muts)* $id)), $thru) - }; - // capture by move into an immutable binding! - (@collect ($id:ident $($tail:tt)*) -> (($($imms:ident)*) $muts:tt), $thru:tt) => { - __guard_impl!(@collect ($($tail)*) -> (($($imms)* $id) $muts), $thru) - }; - - // 3. splitting (for new syntax) - - // done with pattern (and it's LPED=X) - (@split (else { $($diverge:tt)* } = $($tail:tt)*) -> ($pat:tt)) => { - __guard_impl!(@collect $pat -> (() ()), [$pat ($($tail)*) ({ $($diverge)* })]) - }; - - // done with pattern (and it's LP=XED) - (@split (= $($tail:tt)*) -> ($pat:tt)) => { - __guard_impl!(@split expr ($($tail)*) -> ($pat ())) - }; - - // found a token in the pattern - (@split ($head:tt $($tail:tt)*) -> (($($pat:tt)*))) => { - __guard_impl!(@split ($($tail)*) -> (($($pat)* $head))) - }; - - // found an "else DIVERGE" in the expr - (@split expr (else { $($tail:tt)* }) -> ($pat:tt $expr:tt)) => { - __guard_impl!(@collect $pat -> (() ()), [$pat $expr ({ $($tail)* })]) - }; - - // found an else in the expr with more stuff after it - (@split expr (else { $($body:tt)* } $($tail:tt)*) -> ($pat:tt ($($expr:tt)*))) => { - __guard_impl!(@split expr ($($tail)*) -> ($pat ($($expr)* else { $($body)* }))) - }; - - // found another token in the expr - (@split expr ($head:tt $($tail:tt)*) -> ($pat:tt ($($expr:tt)*))) => { - __guard_impl!(@split expr ($($tail)*) -> ($pat ($($expr)* $head))) - }; - - // 4. entry points - - // new syntax - (let $($tail:tt)*) => { - __guard_impl!(@split ($($tail)*) -> (())) - // | | | - // | | ^ pattern - // | ^ tail to be split into "PAT = EXPR else DIVERGE" - // ^ first pass will do the parsing - }; -} - -macro_rules! guard { - ($($input:tt)*) => { - __guard_impl!($($input)*) - }; -} |