type-errors-pretty: Combinators for writing pretty type errors easily

[ library, mpl, type-errors, types ] [ Propose Tags ]

This library provides replacements for the ErrorMessage constructors to write the text of custom error messages easily.


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Versions [faq] 0.0.0.0
Change log CHANGELOG.md
Dependencies base (>=4.10.1.0 && <4.13) [details]
License MPL-2.0
Copyright 2019 Dmitrii Kovanikov
Author Dmitrii Kovanikov
Maintainer Dmitrii Kovanikov <kovanikov@gmail.com>
Category Types, Type Errors
Home page https://github.com/chshersh/type-errors-pretty
Bug tracker https://github.com/chshersh/type-errors-pretty/issues
Source repo head: git clone https://github.com/chshersh/type-errors-pretty.git
Uploaded by shersh at Mon Jul 15 06:29:08 UTC 2019
Distributions NixOS:0.0.0.0
Downloads 68 total (46 in the last 30 days)
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Status Hackage Matrix CI
Docs available [build log]
Last success reported on 2019-07-15 [all 1 reports]

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Readme for type-errors-pretty-0.0.0.0

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type-errors-pretty

pretty-bug Build status Hackage Stackage Lts Stackage Nightly MPL-2.0 license

"It is important that we forgive ourselves for making mistakes. We need to learn from our errors and move on."

― Steve Maraboli, Life, the Truth, and Being Free

Combinators for writing pretty type errors easily. The word pretty here doesn't mean that the resulting type errors will be pretty (though, I believe they will be awesome), but the way the type errors are defined in your code is pretty.

If you're interested in motivation behind using type errors at first place, you can read the following blog post:

The type-errors-pretty library allows you to write the text of custom compile-time error messages with less effort in the following way:

import Type.Errors.Pretty (type (<>), type (%))


type MessageText (e1 :: k) (e2 :: k) (es :: [k])
    = "You require the following two effects from your computation:"
    % ""
    % "    '" <> e1 <> "' and '" <> e2 <> "'"
    % ""
    % "However, your monad is capable of performing only the following effects:"
    % ""
    % "    " <> es

Acknowledgement

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