# Summary

This is a large architectural change to the Hyperlinker.

  * extract link (and now also type) information from `.hie` instead
    of doing ad-hoc SYB traversals of the `RenamedSource`. Also
    adds a superb type-on-hover feature (#715).

 * re-engineer the lexer to avoid needless string conversions. By going
    directly through GHC's `P` monad and taking bytestring slices, we
    avoid a ton of allocation and have better handling of position
    pragmas and CPP.

In terms of performance, the Haddock side of things has gotten _much_
more efficient. Unfortunately, much of this is cancelled out by the
increased GHC workload for generating `.hie` files. For the full set of
boot libs (including `ghc`-the-library)

  * the sum of total time went down by 9-10% overall
  * the sum of total allocations went down by 6-7%

# Motivation

Haddock is moving towards working entirely over `.hi` and `.hie` files.
This change means we no longer need the `RenamedSource` from
`TypecheckedModule` (something which is _not_ in `.hi` files).

# Details

Along the way a bunch of things were fixed:

 * Cross package (and other) links are now more reliable (#496)
 * The lexer tries to recover from errors on every line (instead of at CPP
    boundaries)
 * `LINE`/`COLUMN` pragmas are taken into account
 * filter out zero length tokens before rendering
 * avoid recomputing the `ModuleName`-based `SrcMap`
 * remove the last use of `Documentation.Haddock.Utf8` (see  #998)
 * restructure temporary folder logic for `.hi`/`.hie` model

Alec Theriault authored 6 years ago and Simon Jakobi committed 6 years ago

Since the hyperlinker backend now relies on the GHC tokenizer, something
like 'Bar.Baz.foo' already gets bunched together into one token (as
opposed to being spread across 'Bar', '.', 'Baz', '.', and 'foo').

Alec Theriault authored 6 years ago and Alex Biehl committed 6 years ago

Since the hyperlinker backend now relies on the GHC tokenizer, something
like 'Bar.Baz.foo' already gets bunched together into one token (as
opposed to being spread across 'Bar', '.', 'Baz', '.', and 'foo').

Alec Theriault authored 7 years ago and Alex Biehl committed 7 years ago

* Start changing to use GHC lexer

* better cpp

* Change SrcSpan to RealSrcSpan

* Remove error

* Try to stop too many open files

* wip

* wip

* Revert "wip"

This reverts commit b605510a195f26315e3d8ca90e6d95a6737553e1.

Conflicts:
	haddock-api/haddock-api.cabal
	haddock-api/src/Haddock/Interface.hs

* Remove pointless 'caching'

* Use dlist rather than lists when finding vars

* Use a map rather than list

* Delete bogus comment

* Rebase followup

Things now run using the GHC lexer. There are still

  - stray debug statements
  - unnecessary changes w.r.t. master

* Cleaned up differences w.r.t. current Haddock HEAD

Things are looking good. quasiquotes in particular look beautiful: the
TH ones (with Haskell source inside) colour/link their contents too!

Haven't yet begun to check for possible performance problems.

* Support CPP and top-level pragmas

The support for these is hackier - but no more hacky than the existing
support.

* Tests pass, CPP is better recognized

The tests were in some cases altered: I consider the new output to be more
correct than the old one....

* Fix shrinking of source without tabs in test

* Replace 'Position'/'Span' with GHC counterparts

Replaces 'Position' -> 'GHC.RealSrcLoc' and 'Span' -> 'GHC.RealSrcSpan'.

* Nits

* Forgot entry in .cabal

* Update changelog