Oleg Grenrus pushed to branch wip/shorter-this-module-links at Glasgow Haskell Compiler / GHC

Commits:

• b520943e
  by Oleg Grenrus at 2025-09-14T19:15:25+03:00

  Use showUnique in internalAnchorIdent
  
  Showing the key of Unique as a number is generally not a great idea.
  GHC Unique has a tag in high bits, so the raw number is unnecessarily
  big.
  
  So now we have
  
  ```html
  <a href="#l-rvgK"><span class="hs-identifier hs-var hs-var">bar</span></a>
  ```
  
  instead of
  
  ```html
  <a href="#local-6989586621679015689"><span class="hs-identifier hs-var hs-var">bar</span></a>
  ```
  
  Together with previous changes of shorter intra-module links the effect
  on compressed files is not huge, that is expected as we simply remove
  repetitive contents which pack well.
  
  ```
  12_694_206  Agda-2.9.0-docs-orig.tar.gz
  12_566_065  Agda-2.9.0-docs.tar.gz
  ```
  
  However when unpacked, the difference can be significant,
  e.g. Agda's largest module source got 5% reduction:
  
  ```
  14_230_117  Agda.Syntax.Parser.Parser.html
  13_422_109  Agda.Syntax.Parser.Parser.html
  ```
  
  The whole hyperlinked source code directory got similar reduction
  
  ```
  121M	Agda-2.9.0-docs-orig/src
  114M	Agda-2.9.0-docs/src
  ```
  
  For the reference, sources are about 2/3 of the generated haddocks
  
  ```
  178M	Agda-2.9.0-docs-old
  172M	Agda-2.9.0-docs
  ```
  
  so we get around 3.5% size reduction overall. Not bad for a small local
  changes.
  

1 changed file:

• utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker/Renderer.hs

Changes:

 import GHC.Iface.Ext.Utils (emptyNodeInfo, isEvidenceContext)

 import GHC.Types.Name (Name, getOccString, isInternalName, nameModule, nameUnique)

 import GHC.Types.SrcLoc

-import GHC.Types.Unique (getKey)

+import GHC.Types.Unique (showUnique)

 import GHC.Unit.Module (Module, ModuleName, moduleNameString)

 import GHC.Utils.Encoding (utf8DecodeByteString)

 import System.FilePath.Posix ((</>))

 externalAnchorIdent = hypSrcNameUrl

 internalAnchorIdent :: Name -> String

-internalAnchorIdent = ("local-" ++) . show . getKey . nameUnique

+internalAnchorIdent = ("l-" ++) . showUnique . nameUnique

 -- | Generate the HTML hyperlink for an identifier

 hyperlink :: Module -> SrcMaps -> Identifier -> Html -> Html