madlang: Randomized templating language DSL

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Madlang is a text templating language written in Haskell, meant to explore computational creativity and generative literature.

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Dependencies ansi-wl-pprint, base (>=4.11 && <5), binary, composition-prelude (>=, containers, directory, file-embed, http-client, http-client-tls, madlang, megaparsec (>=6.0), MonadRandom, mtl, optparse-applicative, random-shuffle, recursion-schemes, tar, template-haskell, text, th-lift-instances, titlecase (>=1.0), zip-archive, zlib [details]
License BSD-3-Clause
Copyright Copyright: (c) 2016-2018 Vanessa McHale
Author Vanessa McHale
Category Web
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Source repo head: darcs get
Uploaded by vmchale at Sat Apr 7 16:05:51 UTC 2018
Distributions NixOS:
Executables madlang
Downloads 14020 total (311 in the last 30 days)
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Madlang DSL for generating random text

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This is the Madlang DSL for generating text. You specify a template, and Madlang will create randomized text from the template.

Madlang is an interpreted language, written in Haskell. Madlang can be used as an EDSL for Haskell or using the command-line interpreter.

Madlang is intended to explore computational creativity and provide an easy way to get started with generative literature.


Binary Releases

Head over to the releases page and grab a binary for your platform.


If you do not see you platform listed, you will have to install from source. Download cabal and GHC. Then:

 $ cabal update
 $ cabal new-install madlang

You may need to add $HOME/.local/bin to your PATH. To do so:

 $ echo 'export PATH=$HOME/.local/bin:$PATH' >> $HOME/.bashrc
 $ source $HOME/.bashrc


The smallest program possible in Madlang is simply a return declaration, viz.

    1.0 "heads"
    1.0 "tails"

The :return tells us this that this will be the final value when run, while the numbers in front of the strings denote relative weights. Save this as gambling.mad, and run

 $ madlang run gambling.mad

Now let's try something a little more complicated:

:define person
    1.0 "me"
    1.0 "you"

    1.0 "The only one of us walking out of this room alive is going to be " person "."

A bit more sinister, perhaps. The :define statement there declares a new identifier, which we can later reference. Save this as fate.mad and run:

 $ madlang run fate.mad
 The only one of us walking out of this room alive is going to be you.

We can also refer to another identifier within a :define block.

:define coin
    1.0 "heads"
    1.0 "tails"

:define realisticCoin
    1.0 coin
    0.03 "on its side"

:return realisticCoin

In addition to identifiers, we can also define categories. Categories are just groups of identifiers. We can define one like so:

:define color
    1.0 "yellow"
    1.0 "blue"

:define texture
    1.0 "soft"
    1.0 "scratchy"
    1.0 "dimpled"

:category adjective
    | color
    | texture

    1.0 adjective

Then, when we can adjective, it will pick one of "yellow", "blue",… "dimpled" with equal probability.

Finally, one of the most powerful features of madlang is the ability to include libraries in a file. Open the following and save it as gambling.mad:


:define coin
    1.0 "heads"
    1.0 "tails"

Then, open the following and save it in the same directory as realistic-gambling.mad:

:include gambling.mad

:define realisticGambling
    1.0 gambling-coin
    0.03 "on its side"

    1.0 realisticGambling

Then run it with:

 $ madlang run realistic-gambling.mad

madlang comes with several libraries prepackaged. You can install them for the current user with:

 $ madlang install

Try this out:

:include colors.mad

:define weirdDog
    1.0 colors-color "dog"

    1.0 "On my walk today I saw a " weirdDog "."


You can use Madlang as a Haskell EDSL, generating values of type RandTok. This can be done a couple ways. One is to use the file embedder:

randomText :: RandTok
randomText = $(madFile "mad-src/some-bot.mad")

While the other is to use the madlang quasi-quoter:

randomText :: RandTok
randomText = [madlang|
:include adjectives.mad

    1.0 "I am feeling very " adjectives-adjective " today."

You can then transform this into a random text file with:

generateText :: IO Text
generateText = run randomText


There is a Shakespearean insult generator available to test out at my site. For a look at using Madlang as an EDSL, check out my recursion scheme generator



There is a vim plugin available here.

Project Templates

There is a project template bundled with pi, which you can install with

 $ curl -LSfs | sh -s -- --git vmchale/project-init

and invoke with

 $ pi new madlang story


You can view documentation for madlang on Linux, Mac, or BSD by typing:

 $ man madlang



Contributions, bug reports, and feature requests are emphatically welcome. Please see the guide for more specific details.

Release Naming

Releases are named using the releases.mad file found here. You will need to install the standard libraries using

 $ madlang install

before running

 $ just name