1. Add ale.setup and ale.setup.buffer for pure Lua configuration.
2. Update many global settings to use Booleans instead of numbers to
make types easiert to work with in Lua.
3. Radically reformat documentation and fix errors to make
documentation more usable for Neovim users.
* add prolog/swipl linter
* use load_files/2 instead of read_term/2
Because it also checks some semantic warnings / errors
not only syntactic warnings / errors.
e.g.:
* singleton warning
* discontiguous warning
* ...
cf. http://www.swi-prolog.org/pldoc/doc_for?object=style_check/1
* support error messages with no line number
:- module(module_name, [pred/0]).
causes
ERROR: Exported procedure module_name:pred/0 is not defined
* add test for prolog/swipl handler
* cosmetic fixes
* detect timeout using SIGALRM
* rename g:prolog_swipl_goals to g:prolog_swipl_load
* write doc for prolog/swipl linter
* update toc and README
* fix ignore patterns
