Auto completions related notes

[geraldus]

There is some mess around completions. We have:

• haskell-completions.el provides:
  • hard-coded keywords list
  • hard-coded pragma names list
  • completion prefix grabbing functionality
  • non-interactive completion function:
  • pragmas, options, extensions, keywords
  • synchronous completion function, which completes:
  • pragmas, options, extensions, keywords without REPL
  • identifiers from REPL if it is available
  • modules for import statement from REPL if it is available
• haskell-complete-module.el provides:
  • haskell-complete-module-read — very complicated function, interactively completes module name using mini-buffer
• haskell-modules.el depends on haskell-complete-module.el provides:
  • haskell-add-import — this is major use function, others seem to be for internal use; all functions depend on REPL, if it's not available haskell-add-import reads module name from mini-buffer

haskell-complete-module-read is used in^[1]:

• haskell-mode-contextual-space from haskell.el (I didn't understand what does this function do yet)
• haskell-process-suggest-imports from haskell-load.el
• haskell-add-import from haskell-modules.el

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• [x] research if haskell-completions-sync-completions-at-point should cover a case when REPL is not available, e.g. provide dabbrev completions (at least Emacs and company)^[2]
• [ ] research possibility of merging haskell-modules.el and haskell-complete-module.el
• [ ] research possibility of merging two above packages with haskell-completions.el
• [ ] research if we really need all this stuff to import modules

Related to #215

[gracjan]

Thanks for the summary.

Note that pragmas, options, extensions could work without REPL, but it is not connected.

[geraldus]

research if haskell-completions-sync-completions-at-point should cover a case when REPL is not available, e.g. provide dabbrev completions (at least Emacs and company)

It was decided not to deal with dabbrev, company-mode seems to handle this already. In case of vanilla Emacs, users can run dabbrev-expansion directly or add another dabbrev completion provider to completion-at-point-functions hook