Enum cfg_expr::expr::Predicate

pub enum Predicate<'a> {
    Target(TargetPredicate),
    Test,
    DebugAssertions,
    ProcMacro,
    Feature(&'a str),
    TargetFeature(&'a str),
    Flag(&'a str),
    KeyValue {
        key: &'a str,
        val: &'a str,
    },
}

A single predicate in a cfg() expression

Variants

Target

A target predicate, with the target_ prefix

Tuple Fields of Target

0: TargetPredicate

Test

Whether rustc’s test harness is enabled

DebugAssertions

Enabled when compiling without optimizations.

ProcMacro

Enabled for crates of the proc_macro type.

Feature

A feature = "<name>"

Tuple Fields of Feature

0: &'a str

TargetFeature

target_feature

Tuple Fields of TargetFeature

0: &'a str

Flag

A generic bare predicate key that doesn’t match one of the known options, eg cfg(bare)

Tuple Fields of Flag

0: &'a str

KeyValue

A generic key = “value” predicate that doesn’t match one of the known options, eg cfg(foo = "bar")

Fields of KeyValue

key: &'a strval: &'a str

Trait Implementations

impl<'a> Debug for Predicate<'a>

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

Formats the value using the given formatter.

impl<'a> PartialEq<Predicate<'a>> for Predicate<'a>

fn eq(&self, other: &Predicate<'a>) -> bool

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

fn ne(&self, other: &Predicate<'a>) -> bool

This method tests for !=.

impl<'a> StructuralPartialEq for Predicate<'a>