Add dynamic diagnostic

CONTRIBUTING.md

@@ -23,7 +23,7 @@
 
 ## Introduction
 
-Thank you so much for your interest in contributing!. All types of contributions are encouraged and valued. See the [table of contents](#toc) for different ways to help and details about how this project handles them!📝
+Thank you so much for your interest in contributing! All types of contributions are encouraged and valued. See the [table of contents](#toc) for different ways to help and details about how this project handles them!📝
 
 Please make sure to read the relevant section before making your contribution! It will make it a lot easier for us maintainers to make the most of it and smooth out the experience for all involved. 💚
 

src/dynamic_diagnostic.rs

@@ -0,0 +1,72 @@
+use std::{
+    error::Error,
+    fmt::{Debug, Display},
+};
+
+use crate::Diagnostic;
+
+/// Diagnostic that can be created at runtime.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct DynamicDiagnostic {
+    /// Displayed diagnostic description
+    pub description: String,
+    /// Unique diagnostic code to look up more information
+    /// about this Diagnostic. Ideally also globally unique, and documented
+    /// in the toplevel crate's documentation for easy searching.
+    /// Rust path format (`foo::bar::baz`) is recommended, but more classic
+    /// codes like `E0123` will work just fine.
+    pub code: Option<String>,
+}
+
+impl Display for DynamicDiagnostic {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", &self.description)
+    }
+}
+
+impl Error for DynamicDiagnostic {}
+
+impl Diagnostic for DynamicDiagnostic {
+    fn code<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        self.code
+            .as_ref()
+            .map(Box::new)
+            .map(|c| c as Box<dyn Display>)
+    }
+}
+
+impl DynamicDiagnostic {
+    /// Create a new dynamic diagnostic with the given description.
+    ///
+    /// # Examples
+    /// ```
+    /// use miette::{Diagnostic, DynamicDiagnostic};
+    ///
+    /// let diag = DynamicDiagnostic::new("Oops, something went wrong!");
+    /// assert_eq!(diag.to_string(), "Oops, something went wrong!");
+    /// assert_eq!(diag.description, "Oops, something went wrong!");
+    /// ```
+    pub fn new(description: impl Into<String>) -> Self {
+        Self {
+            description: description.into(),
+            code: None,
+        }
+    }
+
+    /// Return new diagnostic with the given code.
+    ///
+    /// # Examples
+    /// ```
+    /// use miette::{Diagnostic, DynamicDiagnostic};
+    ///
+    /// let diag = DynamicDiagnostic::new("Oops, something went wrong!").with_code("foo::bar::baz");
+    /// assert_eq!(diag.description, "Oops, something went wrong!");
+    /// assert_eq!(diag.code, Some("foo::bar::baz".to_string()));
+    /// ```
+    pub fn with_code(self, code: impl Into<String>) -> Self {
+        Self {
+            code: Some(code.into()),
+            ..self
+        }
+    }
+}

src/lib.rs

@@ -249,7 +249,7 @@
 //! To construct your own simple adhoc error use the [miette!] macro:
 //! ```rust
 //! // my_app/lib/my_internal_file.rs
-//! use miette::{IntoDiagnostic, Result, WrapErr, miette};
+//! use miette::{miette, IntoDiagnostic, Result, WrapErr};
 //! use semver::Version;
 //!
 //! pub fn some_tool() -> Result<Version> {
@@ -619,6 +619,7 @@
 //! [`ariadne`](https://github.com/zesterer/ariadne), which is MIT licensed.
 pub use miette_derive::*;
 
+pub use dynamic_diagnostic::*;
 pub use error::*;
 pub use eyreish::*;
 #[cfg(feature = "fancy-no-backtrace")]
@@ -631,6 +632,7 @@ pub use protocol::*;
 
 mod chain;
 mod diagnostic_chain;
+mod dynamic_diagnostic;
 mod error;
 mod eyreish;
 #[cfg(feature = "fancy-no-backtrace")]