" Maintainer: Paulo Moura <[email protected]>
" Revised on: 2008.06.02
" Language: Logtalk

" This Logtalk indent file is a modified version of the Prolog
" indent file written by Gergely Kontra

" Only load this indent file when no other was loaded.
if exists("b:did_indent")
finish
endif

let b:did_indent = 1

setlocal indentexpr=GetLogtalkIndent()
setlocal indentkeys-=:,0#
setlocal indentkeys+=0%,-,0;,>,0)

" Only define the function once.
if exists("*GetLogtalkIndent")
finish
endif

function! GetLogtalkIndent()
" Find a non-blank line above the current line.
let pnum = prevnonblank(v:lnum - 1)
" Hit the start of the file, use zero indent.
if pnum == 0
return 0
endif
let line = getline(v:lnum)
let pline = getline(pnum)

let ind = indent(pnum)
" Previous line was comment -> use previous line's indent
if pline =~ '^\s*%'
retu ind
endif
" Check for entity opening directive on previous line
if pline =~ '^\s*:-\s\(object\|protocol\|category\)\ze(.*,$'
let ind = ind + &sw
" Check for clause head on previous line
elseif pline =~ ':-\s*\(%.*\)\?$'
let ind = ind + &sw
" Check for entity closing directive on previous line
elseif pline =~ '^\s*:-\send_\(object\|protocol\|category\)\.\(%.*\)\?$'
let ind = ind - &sw
" Check for end of clause on previous line
elseif pline =~ '\.\s*\(%.*\)\?$'
let ind = ind - &sw
endif
" Check for opening conditional on previous line
if pline =~ '^\s*\([(;]\|->\)' && pline !~ '\.\s*\(%.*\)\?$' && pline !~ '^.*\([)][,]\s*\(%.*\)\?$\)'
let ind = ind + &sw
endif
" Check for closing an unclosed paren, or middle ; or ->
if line =~ '^\s*\([);]\|->\)'
let ind = ind - &sw
endif
return ind
endfunction