Trait BooleanErrors 

pub trait BooleanErrors {
    // Required methods
    fn error_if_false(
        self,
        context: impl AsRef<str>,
    ) -> Result<bool, ErrorMessage>;
    fn error_if_true(
        self,
        context: impl AsRef<str>,
    ) -> Result<bool, ErrorMessage>;
    fn error_dyn_if_false(
        self,
        context: impl FnOnce() -> String,
    ) -> Result<bool, ErrorMessage>;
    fn error_dyn_if_true(
        self,
        context: impl FnOnce() -> String,
    ) -> Result<bool, ErrorMessage>;
}

This trait allows one to turn bools into ErrorMessages, when they have a certain value.

This allows for cool code like this:

use errors_with_context::{BooleanErrors, ErrorMessage};
let path = Path::new("test.file");
path.exists()
    .error_if_false("Expected file to exist!")?;

or with more dynamic context:

use errors_with_context::prelude::*;
let path = Path::new("test.file");
path.exists()
    .error_dyn_if_false(|| format!("Expected file '{}' to exist!", path.display()))?;

Very useful, when doing lots of checks that aren’t immediately errors.

Required Methods

fn error_if_false(self, context: impl AsRef<str>) -> Result<bool, ErrorMessage>

If the bool is true, return it Ok(bool).
If the bool is false, return an Err(ErrorMessage) with the provided context string..

use errors_with_context::prelude::*;
let path = Path::new("test.file");
path.exists()
    .error_if_false("Expected file to exist!")?;

fn error_if_true(self, context: impl AsRef<str>) -> Result<bool, ErrorMessage>

If the bool is false, return it wrapped in a Ok(bool).
If the bool is true, return an Err(ErrorMessage) with the provided context string.

use errors_with_context::prelude::*;
let path = Path::new("test.file");
path.exists()
    .not()
    .error_if_true("Expected file to exist!")?;

fn error_dyn_if_false( self, context: impl FnOnce() -> String, ) -> Result<bool, ErrorMessage>

If the bool is true, return it Ok(bool).
If the bool is false, compute the context and return an Err(ErrorMessage).

use errors_with_context::prelude::*;
let path = Path::new("test.file");
path.exists()
    .error_dyn_if_false(|| format!("Expected file '{}' to exist!", path.display()))?;

fn error_dyn_if_true( self, context: impl FnOnce() -> String, ) -> Result<bool, ErrorMessage>

If the bool is false, return it Ok(bool).
If the bool is true, compute the context and return an Err(ErrorMessage).

use errors_with_context::prelude::*;
let path = Path::new("test.file");
path.exists()
    .not()
    .error_dyn_if_true(|| format!("Expected file '{}' to exist!", path.display()))?;

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 BooleanErrors for bool

fn error_if_false(self, context: impl AsRef<str>) -> Result<bool, ErrorMessage>

fn error_if_true(self, context: impl AsRef<str>) -> Result<bool, ErrorMessage>

fn error_dyn_if_false( self, context: impl FnOnce() -> String, ) -> Result<bool, ErrorMessage>

fn error_dyn_if_true( self, context: impl FnOnce() -> String, ) -> Result<bool, ErrorMessage>

Implementors