Trait Context 

pub trait Context {
    // Required methods
    fn context<S: Into<String>>(self, msg: S) -> Self;
    fn with_context<F, S>(self, f: F) -> Self
       where F: FnOnce() -> S,
             S: Into<String>;
    fn color_context<S: Into<String>>(self, color: Color, msg: S) -> Self;
    fn with_color_context<F, S>(self, f: F) -> Self
       where F: FnOnce() -> (Color, S),
             S: Into<String>;
}

A trait for adding context to an error that will be printed along with the error. Contexts are useful for adding things such as hints (i.e. try –help), or additional information such as the path name on a PermissionDenied error, etc.

NOTE: all contexts print without a trailing newline. This allows a context to print to the same line in different formats (colors, etc.). If a trailing newline is required, you should add it manually.

Required Methods

fn context<S: Into<String>>(self, msg: S) -> Self

A simple context

fn with_context<F, S>(self, f: F) -> Self

where F: FnOnce() -> S, S: Into<String>,

A context that is evaluated lazily when called. This is useful if building the context is expensive or allocates

fn color_context<S: Into<String>>(self, color: Color, msg: S) -> Self

A simple context that will color the output

NOTE: The color is reset at the end of this context even if there is no trailing newline. This allows you to chain multiple contexts on the same line where only part of the context is colored.

fn with_color_context<F, S>(self, f: F) -> Self

where F: FnOnce() -> (Color, S), S: Into<String>,

A context that will color the output and that is evaluated lazily when called. This is useful if building the context is expensive or allocates

NOTE: The color is reset at the end of this context even if there is no trailing newline. This allows you to chain multiple contexts on the same line where only part of the context is colored.

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<T> Context for Result<T, CliError>

fn context<S: Into<String>>(self, msg: S) -> Self

fn color_context<S: Into<String>>(self, color: Color, msg: S) -> Self

fn with_context<F, S>(self, f: F) -> Self

where F: FnOnce() -> S, S: Into<String>,

fn with_color_context<F, S>(self, f: F) -> Self

where F: FnOnce() -> (Color, S), S: Into<String>,

Implementors

impl Context for CliError