Trait VariableEnvironment 

pub trait VariableEnvironment {
    type VarName: Eq + Hash;
    type Var;

    // Required methods
    fn var<Q>(&self, name: &Q) -> Option<&Self::Var>
       where Self::VarName: Borrow<Q>,
             Q: Hash + Eq + ?Sized;
    fn set_var(&mut self, name: Self::VarName, val: Self::Var);
    fn env_vars(&self) -> Cow<'_, [(&Self::VarName, &Self::Var)]>;
}

An interface for setting and getting shell and environment variables.

Required Associated Types

type VarName: Eq + Hash

The type of the name this environment associates for a variable.

type Var

The type of variables this environment holds.

Required Methods

fn var<Q>(&self, name: &Q) -> Option<&Self::Var>

where Self::VarName: Borrow<Q>, Q: Hash + Eq + ?Sized,

Get the value of some variable. The values of both shell-only and environment variables will be looked up and returned.

fn set_var(&mut self, name: Self::VarName, val: Self::Var)

Set the value of some variable, maintaining its status as an environment variable if previously set as such.

fn env_vars(&self) -> Cow<'_, [(&Self::VarName, &Self::Var)]>

Unset the value of some variable (including environment variables). Get all current pairs of environment variables and their values.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<'a, T: ?Sized + VariableEnvironment> VariableEnvironment for &'a mut T

type VarName = <T as VariableEnvironment>::VarName

type Var = <T as VariableEnvironment>::Var

fn var<Q>(&self, name: &Q) -> Option<&Self::Var>

where Self::VarName: Borrow<Q>, Q: Hash + Eq + ?Sized,

fn set_var(&mut self, name: Self::VarName, val: Self::Var)

fn env_vars(&self) -> Cow<'_, [(&Self::VarName, &Self::Var)]>

Implementors

impl<'a, E> VariableEnvironment for EnvRestorer<'a, E>

where E: ?Sized + VariableEnvironment + ExportedVariableEnvironment + UnsetVariableEnvironment + FileDescEnvironment, E::FileHandle: Clone, E::VarName: Clone, E::Var: Clone,

type VarName = <E as VariableEnvironment>::VarName

type Var = <E as VariableEnvironment>::Var

impl<A, FM, L, V, EX, WD, B, N, ERR> VariableEnvironment for Env<A, FM, L, V, EX, WD, B, N, ERR>

where V: VariableEnvironment, N: Hash + Eq,

type VarName = <V as VariableEnvironment>::VarName

type Var = <V as VariableEnvironment>::Var

impl<N, V> VariableEnvironment for VarEnv<N, V>

where N: Eq + Clone + Hash, V: Eq + Clone,

type VarName = N

type Var = V