pub struct SyntaxContext(_);
Expand description

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

Implementations

Returns true if self is marked with mark.

Panics if mark is not a valid mark.

Extend a syntax context with a given mark and default transparency for that mark.

Pulls a single mark off of the syntax context. This effectively moves the context up one macro definition level. That is, if we have a nested macro definition as follows:

macro_rules! f {
   macro_rules! g {
       ...
   }
}

and we have a SyntaxContext that is referring to something declared by an invocation of g (call it g1), calling remove_mark will result in the SyntaxContext for the invocation of f that created g1. Returns the mark that was removed.

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).

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).

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));
}

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Returns the “default value” for a type. Read more
Deserialize this value from the given Serde deserializer. Read more
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Feeds a slice of this type into the given Hasher. Read more
This method returns an Ordering between self and other. Read more
Compares and returns the maximum of two values. Read more
Compares and returns the minimum of two values. Read more
Restrict a value to a certain interval. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
Serialize this value into the given Serde serializer. Read more
Note: This method should return true for non-type values.

Auto Trait Implementations

Blanket Implementations

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Returns the argument unchanged.

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