gwernnet.cabal

gwernnet.cabal is the central build configuration for all Haskell code in the gwern.net build system.

Pathbuild/gwernnet.cabal

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Sourcebuild/gwernnet.cabal
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Read this when Use this page when tracing the Haskell build pipeline, generators, metadata code, or backend utility behavior around gwernnet.

Overview

gwernnet.cabal is the central build configuration for all Haskell code in the gwern.net build system. It defines:

• A shared library (gwernnet) exposing 53 modules for site generation
• 13 executable tools for build and maintenance tasks
• Common dependencies and compiler options shared across all components

The configuration uses Cabal 3.0 features like common stanzas to reduce duplication and ensure consistent settings across all build targets.

---

Package Metadata

cabal-version: 3.0
name:          gwernnet
version:       2026.6.1
license:       CC0-1.0
author:        Gwern Branwen
maintainer:    Gwern Branwen
build-type:    Simple
synopsis:      Gwern.net build + maintenance tools (internal)
category:      Web

The version follows a date-based scheme: YYYY.M.patch (e.g. 2026.6.1)

---

Library Modules

The library exposes 53 modules organized by function:

Core Build

Module	Purpose
Annotation	Main annotation/metadata system
LinkMetadata	Link metadata processing
LinkMetadataTypes	Type definitions for metadata
Typography	Pandoc typography transforms
Utils	Common utilities

Annotation Scrapers

Module	Purpose
Annotation.Arxiv	arXiv paper metadata
Annotation.Biorxiv	bioRxiv/medRxiv metadata
Annotation.Gwernnet	Internal site metadata
Annotation.OpenReview	OpenReview paper metadata
Annotation.PDF	PDF document metadata

Link Processing

Module	Purpose
LinkArchive	Archive.org integration
LinkBacklink	Backlink generation
LinkID	Link identification
LinkIcon	Link type icons
LinkLive	Live preview popups
LinkMetadata	Link metadata processing

Text Processing

Module	Purpose
Paragraph	Paragraph transforms
Columns	List column layout
Inflation	Dollar inflation adjustment
Text.Regex	Vendored regex module
Utext	Unicode-rich plain-text rendering

Metadata Handling

Module	Purpose
Metadata.Author	Author name processing
Metadata.Date	Date parsing/formatting
Metadata.Format	Format detection
Metadata.Title	Title processing

Configuration Modules

All Config.* modules contain constants, test cases, and whitelists:

• Config.GenerateSimilar, Config.Inflation, Config.Interwiki
• Config.LinkArchive, Config.LinkID, Config.LinkMetadata
• Config.LinkIcon, Config.LinkLive, Config.LinkSuggester
• Config.Metadata.Author, Config.Metadata.Format, Config.Metadata.Title
• Config.Misc, Config.Paragraph, Config.Tags, Config.Typography, Config.Utext
• Config.XOfTheDay

Other Modules

Module	Purpose
Blog	Blog post generation
Cycle	Cycle detection utilities
GenerateSimilar	Similar link recommendations
GTX	GTX file handling
Image	Image processing
Interwiki	Interwiki link expansion
Query	Extract links/URLs from Pandoc documents
Tags	Tag system
Test	Test utilities
Unique	Unique ID generation
XOfTheDay	Daily featured content

---

Executables

hakyll

Main site generator using Hakyll static site framework.

executable hakyll
  import: exe-common
  main-is: hakyll.hs
  ghc-options: -threaded -rtsopts

preprocessMarkdown

Markdown preprocessing before Pandoc.

executable preprocessMarkdown
  main-is: preprocessMarkdown.hs
  build-depends: gwernnet

generateLinkBibliography

Creates bibliography pages from link metadata.

executable generateLinkBibliography
  main-is: generateLinkBibliography.hs
  ghc-options: -threaded -rtsopts

generateDirectory

Generates directory/index pages.

executable generateDirectory
  main-is: generateDirectory.hs
  ghc-options: -threaded -rtsopts

generateBacklinks

Creates backlink pages showing what links to each page.

executable generateBacklinks
  main-is: generateBacklinks.hs
  ghc-options: -threaded -rtsopts

checkMetadata

Validates metadata consistency.

executable checkMetadata
  main-is: checkMetadata.hs

guessTag

Suggests tags for content.

executable guessTag
  main-is: guessTag.hs

changeTag

Batch tag modification.

executable changeTag
  main-is: changeTag.hs
  ghc-options: -threaded -rtsopts

generateSimilarLinks

Creates "similar links" recommendations.

executable generateSimilarLinks
  main-is: generateSimilarLinks.hs
  ghc-options: -threaded -rtsopts

linkTitler

Adds title metadata to links.

executable linkTitler
  main-is: linkTitler.hs
  ghc-options: -threaded -rtsopts

redirectGuesser

Suggests nginx redirects for likely moved URLs.

executable redirectGuesser
  main-is: redirectGuesser.hs
  ghc-options: -threaded -rtsopts

linkSuggester

Generates link suggestions.

executable linkSuggester
  main-is: linkSuggester.hs
  ghc-options: -threaded -rtsopts

linkExtractor

Extracts links from Markdown.

executable linkExtractor
  main-is: linkExtractor.hs
  ghc-options: -threaded -rtsopts

---

Common Stanza

All components share dependencies and warning defaults via the gwern-common stanza:

common gwern-common
  default-language: Haskell2010

  ghc-options: -Wall

  build-depends:
      base, HTTP, aeson, array, async, ...

Executables import exe-common, which sets hs-source-dirs: app and depends on the gwernnet library. The library stanza sets hs-source-dirs: . and adds ghc-options: -O2.

Compiler Options

Option	Purpose
-O2	Optimization level 2 for the library stanza
-Wall	Enable all warnings
-threaded	Enable threading (some executables)
-rtsopts	Enable runtime options (some executables)

---

Key Dependencies

Core

Package	Purpose
pandoc==3.1.3	Document conversion
pandoc-types	Pandoc AST types
hakyll==4.16.2.0	Static site generator

Web/Network

Package	Purpose
HTTP	HTTP client
http-conduit==2.3.8	Streaming HTTP
http-types	HTTP type definitions
network-uri	URI parsing

Data/Text

Package	Purpose
aeson	JSON parsing
text	Text type
bytestring	Binary data
containers	Maps, sets
vector	Efficient arrays

Regex

Package	Purpose
regex-base	Regex abstraction
regex-tdfa	TDFA regex engine

Other

Package	Purpose
titlecase	Title case conversion
tagsoup	HTML parsing
edit-distance	String similarity
cryptohash	Hashing

---

Version Pins

Some dependencies have exact version pins to ensure reproducible builds:

hakyll==4.16.2.0
http-conduit==2.3.8
pandoc==3.1.3

Additionally, warp is bounded (warp<3.4.13) to work around a compilation failure in warp-3.4.13.

---

Building

cd build/
cabal build all          # Build everything
cabal build hakyll       # Build just hakyll
cabal run hakyll -- ...  # Run with arguments

---

See Also

• hakyll.hs - Main site generator
• sync.sh - Build orchestration script
• Text.Regex - Vendored regex module
• LinkMetadata.hs - Core metadata system