https://github.com/redplanetlabs/defexception

A simple Clojure library to dynamically define Java Exception classes in Clojure.
https://github.com/redplanetlabs/defexception

clojure clojure-library

Last synced: 5 days ago
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A simple Clojure library to dynamically define Java Exception classes in Clojure.

• Host: GitHub
• URL: https://github.com/redplanetlabs/defexception
• Owner: redplanetlabs
• License: epl-1.0
• Created: 2019-08-21T16:48:55.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2022-11-04T19:05:34.000Z (about 2 years ago)
• Last Synced: 2025-01-20T08:06:00.055Z (12 days ago)
• Topics: clojure, clojure-library
• Language: Clojure
• Homepage:
• Size: 36.1 KB
• Stars: 119
• Watchers: 10
• Forks: 7
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE

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README

        
# defexception

[![Build Status](https://travis-ci.org/redplanetlabs/defexception.svg?branch=master)](https://travis-ci.org/redplanetlabs/defexception)

[![Clojars Project](https://img.shields.io/clojars/v/com.rpl/defexception.svg)](https://clojars.org/com.rpl/defexception)

[![cljdoc

badge](https://cljdoc.org/badge/com.rpl/defexception)](https://cljdoc.org/d/com.rpl/defexception/CURRENT)

A simple Clojure library that allows one to dynamically define Java Exception classes in Clojure.

## Motivation

Sometimes you just want a quick Exception class that you can catch

directly. `defexception` uses Java bytecode to dynamically create a

Java class that directly inherits from `clojure.lang.ExceptionInfo`.

The created exception class does not add any behavior to `clojure.lang.ExceptionInfo`.

## Dependency

[deps.edn](https://clojure.org/guides/deps_and_cli) dependency information:

```

com.rpl/defexception {:mvn/version "0.2.5"}

```

[Leiningen](https://github.com/technomancy/leiningen/) dependency information:

```

[com.rpl/defexception "0.2.5"]

```

## Usage

To create your own exception class you can do this:

```clojure

(ns foo.bar

 (:require [com.rpl.defexception :refer [defexception]]))

(defexception MyException)

```

This will create the `foo.bar.MyException` class that inherits from

`clojure.lang.ExceptionInfo`. This will also `import` the class into

the current namespace and create a helper function

`foo.bar/->MyException` to help you construct the exception class.

Now you can do this:

```clojure

(try

  (throw (->MyException "My bad!" {:my-bad 1}))

  (catch MyException e

    (ex-data e)))

;; => {:my-bad 1}

```

The generated `->MyException` helper function has several signatures

to help you instantiate your exception.

```clojure

;; creates an exception with no message or ex-data

(->MyException)

;; creates an exception with only ex-data

(->MyException {:hello 1})

;; creates an exception with only a message

(->MyException "My Bad!")

;; creates an exception with both a message and ex-data

(->MyException "My Bad!" {:hello 1})

;; creates an exception with a message, ex-data and a cause

(->MyException "My Bad!" {:hello 1} (Exception. "The cause"))

```

## AOT compilation

Care was taken to make these exceptions compatible with Clojure's AOT

compilation.

## License

Copyright © 2019 - 2020 Red Planet Labs Inc.

Distributed under the Eclipse Public License version 1.0