Struct syntex_syntax2::codemap::hygiene::SyntaxContext

pub struct SyntaxContext(_);

A SyntaxContext represents a chain of macro expansions (represented by marks).

Methods

impl SyntaxContext

pub fn empty() -> SyntaxContext

pub fn apply_mark(self, mark: Mark) -> SyntaxContext

Extend a syntax context with a given mark

pub fn remove_mark(&mut self) -> Mark

pub fn adjust(&mut self, expansion: Mark) -> Option<Mark>

Adjust this context for resolution in a scope created by the given expansion. For example, consider the following three resolutions of f:

mod foo { pub fn f() {} } // `f`'s `SyntaxContext` is empty.
m!(f);
macro m($f:ident) {
    mod bar {
        pub fn f() {} // `f`'s `SyntaxContext` has a single `Mark` from `m`.
        pub fn $f() {} // `$f`'s `SyntaxContext` is empty.
    }
    foo::f(); // `f`'s `SyntaxContext` has a single `Mark` from `m`
    //^ Since `mod foo` is outside this expansion, `adjust` removes the mark from `f`,
    //| and it resolves to `::foo::f`.
    bar::f(); // `f`'s `SyntaxContext` has a single `Mark` from `m`
    //^ Since `mod bar` not outside this expansion, `adjust` does not change `f`,
    //| and it resolves to `::bar::f`.
    bar::$f(); // `f`'s `SyntaxContext` is empty.
    //^ Since `mod bar` is not outside this expansion, `adjust` does not change `$f`,
    //| and it resolves to `::bar::$f`.
}

This returns the expansion whose definition scope we use to privacy check the resolution, or None if we privacy check as usual (i.e. not w.r.t. a macro definition scope).

pub fn glob_adjust(
    &mut self,
    expansion: Mark,
    glob_ctxt: SyntaxContext
) -> Option<Option<Mark>>

Adjust this context for resolution in a scope created by the given expansion via a glob import with the given SyntaxContext. For example,

m!(f);
macro m($i:ident) {
    mod foo {
        pub fn f() {} // `f`'s `SyntaxContext` has a single `Mark` from `m`.
        pub fn $i() {} // `$i`'s `SyntaxContext` is empty.
    }
    n(f);
    macro n($j:ident) {
        use foo::*;
        f(); // `f`'s `SyntaxContext` has a mark from `m` and a mark from `n`
        //^ `glob_adjust` removes the mark from `n`, so this resolves to `foo::f`.
        $i(); // `$i`'s `SyntaxContext` has a mark from `n`
        //^ `glob_adjust` removes the mark from `n`, so this resolves to `foo::$i`.
        $j(); // `$j`'s `SyntaxContext` has a mark from `m`
        //^ This cannot be glob-adjusted, so this is a resolution error.
    }
}

This returns None if the context cannot be glob-adjusted. Otherwise, it returns the scope to use when privacy checking (see adjust for details).

pub fn reverse_glob_adjust(
    &mut self,
    expansion: Mark,
    glob_ctxt: SyntaxContext
) -> Option<Option<Mark>>

Undo glob_adjust if possible:

if let Some(privacy_checking_scope) = self.reverse_glob_adjust(expansion, glob_ctxt) {
    assert!(self.glob_adjust(expansion, glob_ctxt) == Some(privacy_checking_scope));
}

pub fn modern(self) -> SyntaxContext

pub fn outer(self) -> Mark

Trait Implementations

impl Eq for SyntaxContext

impl Default for SyntaxContext

fn default() -> SyntaxContext

Returns the "default value" for a type.

impl Copy for SyntaxContext

impl Hash for SyntaxContext

fn hash<__H>(&self, state: &mut __H) where
    __H: Hasher, 

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].

impl Clone for SyntaxContext

fn clone(&self) -> SyntaxContext

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SyntaxContext

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl Ord for SyntaxContext

fn cmp(&self, other: &SyntaxContext) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval.

impl PartialEq<SyntaxContext> for SyntaxContext

fn eq(&self, other: &SyntaxContext) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &SyntaxContext) -> bool

This method tests for !=.

impl Serialize for SyntaxContext

fn serialize<S>(
    &self,
    serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error> where
    S: Serializer, 

Serialize this value into the given Serde serializer.

impl<'de> Deserialize<'de> for SyntaxContext

fn deserialize<D>(
    deserializer: D
) -> Result<SyntaxContext, <D as Deserializer<'de>>::Error> where
    D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl PartialOrd<SyntaxContext> for SyntaxContext

fn partial_cmp(&self, other: &SyntaxContext) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &SyntaxContext) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &SyntaxContext) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &SyntaxContext) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &SyntaxContext) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.