https://github.com/weavejester/hashp
A better "prn" for debugging
https://github.com/weavejester/hashp
clojure debugging
Last synced: about 1 month ago
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A better "prn" for debugging
- Host: GitHub
- URL: https://github.com/weavejester/hashp
- Owner: weavejester
- License: mit
- Created: 2019-12-14T03:56:35.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2025-04-01T01:19:23.000Z (about 1 month ago)
- Last Synced: 2025-04-01T01:21:30.508Z (about 1 month ago)
- Topics: clojure, debugging
- Language: Clojure
- Size: 30.3 KB
- Stars: 459
- Watchers: 9
- Forks: 23
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Hashp
Hashp is a better `prn` for debugging Clojure code. Inspired by
projects like [Spyscope][], Hashp (ab)uses data readers to make it
easier to get useful debugging data sent to STDERR.
[spyscope]: https://github.com/dgrnbrg/spyscope
## Usage
Once installed, you can add `#p` in front of any form you wish to
print:
```clojure
(ns example.core)
(defn mean [xs]
(/ (double #p (reduce + xs)) #p (count xs)))
```
It's faster to type than `(prn ...)`, returns the original result, and
produces more useful output by printing the original form, function
and line number:
```
user=> (mean [1 4 5 2])
#p[example.core/mean:4] (reduce + xs) => 12
#p[example.core/mean:4] (count xs) => 4
3.0
```
## Installation
### tools.deps
To use `#p` in a tools.deps project, add the following dependency to
your project's `deps.edn` file:
```edn
{:deps {dev.weavejester/hashp {:mvn/version "0.4.0"}}}
```
You will then need to load the `hashp.core` namespace before using `#p`:
```clojure
(require 'hashp.preload)
```
### Leiningen
To make `#p` globally available to all Leiningen projects, add the
following to `~/.lein/profiles.clj`:
```edn
{:user
{:dependencies [[dev.weavejester/hashp "0.4.0"]]
:injections [(require 'hashp.preload)]}}
```
### Boot
To make `#p` globally available to all Boot projects, add the following
to `~/.boot/profile.boot`:
```clojure
(set-env! :dependencies #(conj % '[dev.weavejester/hashp "0.4.0"]))
(require 'hashp.preload)
(boot.core/load-data-readers!)
```
## Configuration
Hashp can be turned on or off via the `hashp.config/*disable-hashp*`
var. This is checked when `#p` is **initially evaluated**, so if it is
changed, any existing namespace that uses `#p` will need to be reloaded
before the change takes effect.
```
user=> (alter-var-root #'hashp.config/*disable-hashp* (constantly true))
true
user=> (require 'example.core :reload)
nil
user=> (mean [1 4 5 2])
3.0
```
You can also turn the colors off. Hashp respects the [NO_COLOR][]
environment variable, and you can also set it via the
`hashp.config/*disable-color*` var. Unlike `*disable-hashp*`, this is
checked on each print, so there's no need to reload the namespaces.
```
user=> (alter-var-root #'hashp.config/*disable-color* (constantly true))
true
```
Finally, you can change the output writer. By default this is `*err*`,
which outputs to STDOUT, but you can set this to any other print writer,
such as `*out*`.
```
user=> (alter-var-root #'hashp.config/*hashp-output* (constantly *out*))
#object[java.io.PrintWriter 0x2deddab6 "java.io.PrintWriter@2deddab6"]
```
[no_color]: https://no-color.org/
## License
Copyright © 2025 James Reeves
Released under the MIT license.