Add hi2 support

[iquiw]

Add same configuration for hi2 [1], [2] as haskell-indentation.

[1] https://github.com/errge/hi2 [2] http://www.haskell.org/pipermail/haskell-cafe/2013-August/108290.html

[iquiw]

It causes "assignment to free variable" warning at byte compile, but it is not harmful, I think.

The warning can be avoided by using eval-after-load, but I don't know we should do.

 (eval-after-load 'hi2
    '(progn
       (setq hi2-layout-offset 4
             hi2-left-offset 4
             hi2-ifte-offset 4)))

Maybe, better to keep this pending until someone gives an advice?

[tibbe]

Maybe, better to keep this pending until someone gives an advice?

Sounds good.

[hvr]

@iquiw eval-after-load should be perfectly fine, as it makes sure the setq is evaluated as soon as hi2 gets loaded (and thus the defcustoms declaring the variables have been seen).

However, the progn is not needed here, as setq is a single command, i.e. just use

(eval-after-load 'hi2
  '(setq hi2-layout-offset 4
         hi2-left-offset 4
         hi2-ifte-offset 4))

[hvr]

@tibbe why did you add that global(!) tab-width override?

[tibbe]

why did you add that global(!) tab-width override?

Because I have very little to no understanding of elisp. :)

[hvr]

@tibbe I see :-)

in any case, setting tab-width to 4 for Haskell source files is very bad, as the Haskell report hardcodes the tab width to 8 characters; see Haskell 2010, section 10.3 which states

• Tab stops are 8 characters apart.
• A tab character causes the insertion of enough spaces to align the current position with the next tab stop.

and in Emacs tab-width defines how an actual \t in the text file is interpreted.

PS: The haskell-mode initialization code sets the tab-width expliclity to 8 for this reason.

[tibbe]

@hvr this was a failed attempts to have the tab key generate 4 spaces.

[iquiw]

I added this configuration in my local init.el. So closing this pull request for now.