config-value: Simple, layout-based value language similar to YAML or JSON

[ language, library, mit ] [ Propose Tags ]

This package implements a language similar to YAML or JSON but with fewer special cases and fewer dependencies. It emphasizes layout structure for sections and lists, and requires quotes around strings.

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Versions [faq] 0.1, 0.1.1, 0.2, 0.3, 0.4,,, 0.5, 0.5.1, 0.6, 0.6.1, 0.6.2,, 0.6.3,,,, 0.8 (info)
Change log
Dependencies array (>=0.4 && <0.6), base (>=4.8 && <4.15), containers (>=0.5 && <0.7), pretty (>= && <1.2), text (>= && <1.3) [details]
License MIT
Copyright 2015-2016,2019 Eric Mertens
Author Eric Mertens
Category Language
Home page
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Source repo head: git clone git://
Uploaded by EricMertens at 2020-09-26T18:20:05Z
Distributions Debian:, NixOS:0.8
Downloads 11242 total (55 in the last 30 days)
Rating 2.25 (votes: 2) [estimated by Bayesian average]
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Status Hackage Matrix CI
Docs available [build log]
Last success reported on 2020-09-26 [all 1 reports]


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Maintainer's Corner

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Readme for config-value-0.8

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This package implements a simple, layout-based value definition language used for supplying configuration values to various applications.

Before starting to use config-value, you probably want to read the documentation for config-schema to see the user-friendly way to wrap this library.

Live Demo

The config-value and config-schema packages are available in a live demo.


-- Line comments until newline
      {} -- empty section


    {- Block comments
       {- nested comments -}
       "O'caml style {- strings in comments"
       so you can comment out otherwise valid
       portions of your config
    atoms      : yes

    decimal    : -1234
    hexadecimal: 0x1234
    octal      : 0o1234
    binary     : 0b1010
    floating   : 12.34e56

   * sections: in-lists
     next-section: still-in-list
   * [ "inline", "lists" ]
   * * "nestable"
     * "layout"
     * "lists"
   * 3

unicode : "standard Haskell format strings (1 ≤ 2)\x2228(2 ≤ 3)"


The language supports: Strings, Atoms, Integers, Lists, Nested Sections.

Sections are layout based. The contents of a section must be indented further than the section heading. The whitespace between a section heading and its colon is not significant. Section names must start with a letter and may contain letters, numbers, dashes (-), underscores (_), and periods (.).

Lists are either layout based with * prefixes or inline surrounded by [ and ] delimited by ,

Strings are surrounded by " and use Haskell-style escapes.

Numbers support decimal, hexadecimal (0x), octal (0o), and binary (0b).

Atoms follow the same lexical rule as section heading.