cabal-file

cabal-file is a library on top of the hackage-security library for accessing cabal files and versions, and also a small tool for getting and comparing .cabal files.

Since it accesses package and .cabal file data directly from the local Hackage repo cache index tar archive under ~/.cabal/ it is quite fast.

Usage

List all Hackage packages:

$ cblfile list | grep ghcide
ghcide

List versions of a package:

$ cblfile list pandoc
0.4
:
:
2.9.2.1

Diff .cabal files of package versions

$ cblfile diff pandoc 2.8 2.9.2.1
--- pandoc-2.8.cabal    2020-05-24 19:47:58.487921450 +0800
+++ pandoc-2.9.2.1.cabal        2020-05-24 19:47:58.487921450 +0800
@@ -1,10 +1,10 @@
 name:            pandoc
-version:         2.8
+version:         2.9.2.1
 cabal-version:   2.0
:
:

Latest version of a package:

$ cblfile latest extra
1.7.1

Timestamp for the latest .cabal file (or for a specific version):

$ cblfile date dhall
2020-05-19 02:18:01 UTC

Save a .cabal file (latest or specific version)

$ cblfile get purescript
$ ls purescript.cabal
purescript.cabal

Check package source metadata:

$ cblfile metadata tls-1.5.4
Size: 150171
SHA256 Hash "ce42bfa581a50f62776581da4b86408ebb1a51bc6cb2f95ad0a2ac7caa19a437"

Depends output

cblfile depends outputs quite verbose package dependency lists.

Library

For library documentation see the Hackage.Index documentation.

For example usage see app/Cmds.hs.

Motivation

I originally wrote the depends command for displaying dependency information about packages in a more friendly way.

Later, since hdiff is out of sync for some packages, and I use it particularly for comparing versions of .cabal files, I decided to create the diff command. Realising I could pull .cabal files direct from the cabal index cache, the rest of cabal-file flowed on from there.

Related

If you want full diffs of Hackage sources you can try out cabal-diff from cabal-extras.