haskell-frontmatter
Attoparsec parsers for YAML frontmatter as used in Jekyll. Because of how
Data.Yaml
is implemented using Data.Aeson
, the
Data.Yaml.Frontmatter.frontmatterYaml
instance of Parser
works with YAML and
JSON.
Installation
This actually won’t work right now
$ stack install frontmatter
Usage
import Data.Frontmatter
import Data.Yaml (Value)
main = ByteString.readFile "something.md" >>= parseYamlFrontmatter >>= \case
Done ri fm -> do
print (fm :: Value) -- aeson object in the frontmatter (the explicit
-- type required because the parser will return
-- anything with a FromJSON
putStrLn ri -- rest of the document
_ -> error "Parse failure"
See the haddocks for more information. Essentially exports an Attoparsec
parser and some helpers. Usage examples also available at the test
directory.
Why?
I’m working on the Haskell workshop tool
workhs
. In my mind, using markdown file
names as metadata is a very sensible decision. However, I’d like for tutorial
writers to be able to override metadata. Then, Jekyll’s YAML frontmatter format
is a great choice:
- It’s familiar
- It’s very, very easy to implement
License
This software is published under the MIT license. For more information refer to
the LICENSE file.