Cabal

The following metadata fields can be extracted from a cabal file.
These fields are defined in the Cabal specification, currently at version 3.10 and are mapped according to the Codemeta crosswalk for cabal.

Software metadata category	SOMEF metadata JSON path	CABAL metadata file field
description	description[i].result.value	synopsis / description (1)
development_status	development_status[i].result.value	stability
has_package_file	has_package_file[i].result.value	URL of the filename.cabal file
homepage	homepage[i].result.value	homepage (2)
issue_tracker	issue_tracker[i].result.value	bug-reports
license	license[i].result.value	Regex license (3)
package_id	package_id[i].value	name (4)
requirements - value	requirements[i].result.value	(5)
requirements - name	requirements[i].result.name	library.build-depends name (5.1)
requirements - version	requirements[i].result.version	library.build-depends version (5.2)
requirements - development type	requirements[i].result.development_type	"runtime"
version	version[i].result.value	version (6)

---

(1)
- Regex: r'description:\s*(.*?)(?=\n\S|\Z)' → group[1]
- Example: description: text description - Result: text description

(2)
- Regex: re.search(r'homepage:\s*(.*)' → group[1]
- Example: homepage: https://github.com/joshuaclayton/unused#readme - Result: https://github.com/joshuaclayton/unused#readme

(3)
- Regex: r'license:\s*(.*)' → group[1]
- Example: license: BSD-3-Clause - Result: BSD-3-Clause

(4)
- Regex: r'name:\s*(.*)' → group[1]
- Example: name: unused - Result: unused

(5), (5.1), (5.2)

• Regex 1: r'library\s*\n(.*?)(?=\n\S|\Z)' → group[1] --> first look into library
• Regex 2: r'build-depends:\s*(.*?)(?=\n\s*(?:[A-Za-z0-9_-]+\s*:|if\s|\Z)) ' → group[1] --> build-depends into library content
• Regex 3: r'^([a-zA-Z0-9-_]+)\s*(.*?)$' --> extract groups for name and version
• Example:

library
  build-depends:
    Cabal-syntax ^>= 3.17,
    array         >= 0.4.0.1  && < 0.6

• Result value: Cabal-syntax ^>= 3.17
• Result name: Cabal-syntax
• Result version: ^>= 3.17

(6)
- Regex: r'version:\s*(.*)' → group[1]
- Example: version: 0.10.0.0 - Result: 0.10.0.0