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Merge pull request #1165 from serde-rs/jsonmac
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Eliminate local_inner_macros in favor of non-ident macro paths
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@dtolnay
dtolnay authored Aug 1, 2024
2 parents eca2658 + 7633cb7 commit 611b2a4
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Showing 3 changed files with 37 additions and 38 deletions.
71 changes: 35 additions & 36 deletions src/macros.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -50,11 +50,11 @@
/// "comma -->",
/// ]);
/// ```
#[macro_export(local_inner_macros)]
#[macro_export]
macro_rules! json {
// Hide distracting implementation details from the generated rustdoc.
($($json:tt)+) => {
json_internal!($($json)+)
$crate::json_internal!($($json)+)
};
}

Expand All @@ -65,7 +65,7 @@ macro_rules! json {
//
// Changes are fine as long as `json_internal!` does not call any new helper
// macros and can still be invoked as `json_internal!($($json)+)`.
#[macro_export(local_inner_macros)]
#[macro_export]
#[doc(hidden)]
macro_rules! json_internal {
//////////////////////////////////////////////////////////////////////////
Expand All @@ -77,57 +77,57 @@ macro_rules! json_internal {

// Done with trailing comma.
(@array [$($elems:expr,)*]) => {
json_internal_vec![$($elems,)*]
vec![$($elems,)*]
};

// Done without trailing comma.
(@array [$($elems:expr),*]) => {
json_internal_vec![$($elems),*]
vec![$($elems),*]
};

// Next element is `null`.
(@array [$($elems:expr,)*] null $($rest:tt)*) => {
json_internal!(@array [$($elems,)* json_internal!(null)] $($rest)*)
$crate::json_internal!(@array [$($elems,)* $crate::json_internal!(null)] $($rest)*)
};

// Next element is `true`.
(@array [$($elems:expr,)*] true $($rest:tt)*) => {
json_internal!(@array [$($elems,)* json_internal!(true)] $($rest)*)
$crate::json_internal!(@array [$($elems,)* $crate::json_internal!(true)] $($rest)*)
};

// Next element is `false`.
(@array [$($elems:expr,)*] false $($rest:tt)*) => {
json_internal!(@array [$($elems,)* json_internal!(false)] $($rest)*)
$crate::json_internal!(@array [$($elems,)* $crate::json_internal!(false)] $($rest)*)
};

// Next element is an array.
(@array [$($elems:expr,)*] [$($array:tt)*] $($rest:tt)*) => {
json_internal!(@array [$($elems,)* json_internal!([$($array)*])] $($rest)*)
$crate::json_internal!(@array [$($elems,)* $crate::json_internal!([$($array)*])] $($rest)*)
};

// Next element is a map.
(@array [$($elems:expr,)*] {$($map:tt)*} $($rest:tt)*) => {
json_internal!(@array [$($elems,)* json_internal!({$($map)*})] $($rest)*)
$crate::json_internal!(@array [$($elems,)* $crate::json_internal!({$($map)*})] $($rest)*)
};

// Next element is an expression followed by comma.
(@array [$($elems:expr,)*] $next:expr, $($rest:tt)*) => {
json_internal!(@array [$($elems,)* json_internal!($next),] $($rest)*)
$crate::json_internal!(@array [$($elems,)* $crate::json_internal!($next),] $($rest)*)
};

// Last element is an expression with no trailing comma.
(@array [$($elems:expr,)*] $last:expr) => {
json_internal!(@array [$($elems,)* json_internal!($last)])
$crate::json_internal!(@array [$($elems,)* $crate::json_internal!($last)])
};

// Comma after the most recent element.
(@array [$($elems:expr),*] , $($rest:tt)*) => {
json_internal!(@array [$($elems,)*] $($rest)*)
$crate::json_internal!(@array [$($elems,)*] $($rest)*)
};

// Unexpected token after most recent element.
(@array [$($elems:expr),*] $unexpected:tt $($rest:tt)*) => {
json_unexpected!($unexpected)
$crate::json_unexpected!($unexpected)
};

//////////////////////////////////////////////////////////////////////////
Expand All @@ -146,12 +146,12 @@ macro_rules! json_internal {
// Insert the current entry followed by trailing comma.
(@object $object:ident [$($key:tt)+] ($value:expr) , $($rest:tt)*) => {
let _ = $object.insert(($($key)+).into(), $value);
json_internal!(@object $object () ($($rest)*) ($($rest)*));
$crate::json_internal!(@object $object () ($($rest)*) ($($rest)*));
};

// Current entry followed by unexpected token.
(@object $object:ident [$($key:tt)+] ($value:expr) $unexpected:tt $($rest:tt)*) => {
json_unexpected!($unexpected);
$crate::json_unexpected!($unexpected);
};

// Insert the last entry without trailing comma.
Expand All @@ -161,78 +161,78 @@ macro_rules! json_internal {

// Next value is `null`.
(@object $object:ident ($($key:tt)+) (: null $($rest:tt)*) $copy:tt) => {
json_internal!(@object $object [$($key)+] (json_internal!(null)) $($rest)*);
$crate::json_internal!(@object $object [$($key)+] ($crate::json_internal!(null)) $($rest)*);
};

// Next value is `true`.
(@object $object:ident ($($key:tt)+) (: true $($rest:tt)*) $copy:tt) => {
json_internal!(@object $object [$($key)+] (json_internal!(true)) $($rest)*);
$crate::json_internal!(@object $object [$($key)+] ($crate::json_internal!(true)) $($rest)*);
};

// Next value is `false`.
(@object $object:ident ($($key:tt)+) (: false $($rest:tt)*) $copy:tt) => {
json_internal!(@object $object [$($key)+] (json_internal!(false)) $($rest)*);
$crate::json_internal!(@object $object [$($key)+] ($crate::json_internal!(false)) $($rest)*);
};

// Next value is an array.
(@object $object:ident ($($key:tt)+) (: [$($array:tt)*] $($rest:tt)*) $copy:tt) => {
json_internal!(@object $object [$($key)+] (json_internal!([$($array)*])) $($rest)*);
$crate::json_internal!(@object $object [$($key)+] ($crate::json_internal!([$($array)*])) $($rest)*);
};

// Next value is a map.
(@object $object:ident ($($key:tt)+) (: {$($map:tt)*} $($rest:tt)*) $copy:tt) => {
json_internal!(@object $object [$($key)+] (json_internal!({$($map)*})) $($rest)*);
$crate::json_internal!(@object $object [$($key)+] ($crate::json_internal!({$($map)*})) $($rest)*);
};

// Next value is an expression followed by comma.
(@object $object:ident ($($key:tt)+) (: $value:expr , $($rest:tt)*) $copy:tt) => {
json_internal!(@object $object [$($key)+] (json_internal!($value)) , $($rest)*);
$crate::json_internal!(@object $object [$($key)+] ($crate::json_internal!($value)) , $($rest)*);
};

// Last value is an expression with no trailing comma.
(@object $object:ident ($($key:tt)+) (: $value:expr) $copy:tt) => {
json_internal!(@object $object [$($key)+] (json_internal!($value)));
$crate::json_internal!(@object $object [$($key)+] ($crate::json_internal!($value)));
};

// Missing value for last entry. Trigger a reasonable error message.
(@object $object:ident ($($key:tt)+) (:) $copy:tt) => {
// "unexpected end of macro invocation"
json_internal!();
$crate::json_internal!();
};

// Missing colon and value for last entry. Trigger a reasonable error
// message.
(@object $object:ident ($($key:tt)+) () $copy:tt) => {
// "unexpected end of macro invocation"
json_internal!();
$crate::json_internal!();
};

// Misplaced colon. Trigger a reasonable error message.
(@object $object:ident () (: $($rest:tt)*) ($colon:tt $($copy:tt)*)) => {
// Takes no arguments so "no rules expected the token `:`".
json_unexpected!($colon);
$crate::json_unexpected!($colon);
};

// Found a comma inside a key. Trigger a reasonable error message.
(@object $object:ident ($($key:tt)*) (, $($rest:tt)*) ($comma:tt $($copy:tt)*)) => {
// Takes no arguments so "no rules expected the token `,`".
json_unexpected!($comma);
$crate::json_unexpected!($comma);
};

// Key is fully parenthesized. This avoids clippy double_parens false
// positives because the parenthesization may be necessary here.
(@object $object:ident () (($key:expr) : $($rest:tt)*) $copy:tt) => {
json_internal!(@object $object ($key) (: $($rest)*) (: $($rest)*));
$crate::json_internal!(@object $object ($key) (: $($rest)*) (: $($rest)*));
};

// Refuse to absorb colon token into key expression.
(@object $object:ident ($($key:tt)*) (: $($unexpected:tt)+) $copy:tt) => {
json_expect_expr_comma!($($unexpected)+);
$crate::json_expect_expr_comma!($($unexpected)+);
};

// Munch a token into the current key.
(@object $object:ident ($($key:tt)*) ($tt:tt $($rest:tt)*) $copy:tt) => {
json_internal!(@object $object ($($key)* $tt) ($($rest)*) ($($rest)*));
$crate::json_internal!(@object $object ($($key)* $tt) ($($rest)*) ($($rest)*));
};

//////////////////////////////////////////////////////////////////////////
Expand All @@ -254,11 +254,11 @@ macro_rules! json_internal {
};

([]) => {
$crate::Value::Array(json_internal_vec![])
$crate::Value::Array(vec![])
};

([ $($tt:tt)+ ]) => {
$crate::Value::Array(json_internal!(@array [] $($tt)+))
$crate::Value::Array($crate::json_internal!(@array [] $($tt)+))
};

({}) => {
Expand All @@ -268,7 +268,7 @@ macro_rules! json_internal {
({ $($tt:tt)+ }) => {
$crate::Value::Object({
let mut object = $crate::Map::new();
json_internal!(@object object () ($($tt)+) ($($tt)+));
$crate::json_internal!(@object object () ($($tt)+) ($($tt)+));
object
})
};
Expand All @@ -280,9 +280,8 @@ macro_rules! json_internal {
};
}

// The json_internal macro above cannot invoke vec directly because it uses
// local_inner_macros. A vec invocation there would resolve to $crate::vec.
// Instead invoke vec here outside of local_inner_macros.
// Used by old versions of Rocket.
// Unused since https://github.com/rwf2/Rocket/commit/c74bcfd40a47b35330db6cafb88e4f3da83e0d17
#[macro_export]
#[doc(hidden)]
macro_rules! json_internal_vec {
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/missing_colon.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -9,4 +9,4 @@ note: while trying to match `@`
|
| (@array [$($elems:expr,)*]) => {
| ^
= note: this error originates in the macro `json_internal` which comes from the expansion of the macro `json` (in Nightly builds, run with -Z macro-backtrace for more info)
= note: this error originates in the macro `$crate::json_internal` which comes from the expansion of the macro `json` (in Nightly builds, run with -Z macro-backtrace for more info)
2 changes: 1 addition & 1 deletion tests/ui/missing_value.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,4 +9,4 @@ note: while trying to match `@`
|
| (@array [$($elems:expr,)*]) => {
| ^
= note: this error originates in the macro `json_internal` which comes from the expansion of the macro `json` (in Nightly builds, run with -Z macro-backtrace for more info)
= note: this error originates in the macro `$crate::json_internal` which comes from the expansion of the macro `json` (in Nightly builds, run with -Z macro-backtrace for more info)

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