samer@3: "  vim: set sw=4 sts=4:
samer@3: "  Maintainer	: Gergely Kontra <kgergely@mcl.hu>
samer@3: "  Revised on	: 2002.02.18. 23:34:05
samer@3: "  Language	: Prolog
samer@3: 
samer@3: " TODO:
samer@3: "   checking with respect to syntax highlighting
samer@3: "   ignoring multiline comments
samer@3: "   detecting multiline strings
samer@3: 
samer@3: " Only load this indent file when no other was loaded.
samer@3: if exists("b:did_indent")
samer@3:     finish
samer@3: endif
samer@3: 
samer@3: let b:did_indent = 1
samer@3: 
samer@3: setlocal indentexpr=GetPrologIndent()
samer@3: setlocal indentkeys-=:,0#
samer@3: setlocal indentkeys+=0%,0;,0)
samer@3: 
samer@3: " Only define the function once.
samer@3: "if exists("*GetPrologIndent")
samer@3: "    finish
samer@3: "endif
samer@3: 
samer@3: function! GetPrologIndent()
samer@3:     " Find a non-blank line above the current line.
samer@3:     let pnum = prevnonblank(v:lnum - 1)
samer@3:     " Hit the start of the file, use zero indent.
samer@3:     if pnum == 0
samer@3:        return 0
samer@3:     endif
samer@3:     let line = getline(v:lnum)
samer@3:     let pline = getline(pnum)
samer@3: 
samer@3:     let ind = indent(pnum)
samer@3:     " Previous line was comment -> use previous line's indent
samer@3:     if pline =~ '^\s*%'
samer@3: 	retu ind
samer@3:     endif
samer@3:     " Check for clause head on previous line
samer@3:     if pline =~ ':-\s*\(%.*\)\?$'
samer@3: 	let ind = ind + &sw
samer@3:     " Check for end of clause on previous line
samer@3:     elseif pline =~ '\.\s*\(%.*\)\?$'
samer@3: 	let ind = ind - &sw
samer@3:     endif
samer@3:     " Check for opening conditional on previous line
samer@3:     if pline =~ '^\s*\([(;]\|->\)'
samer@3: 	let ind = ind + &sw
samer@3:     endif
samer@3:     " Check for closing an unclosed paren, or middle ; or ->
samer@3:     if line =~ '^\s*\([);]\|->\)'
samer@3: 	let ind = ind - &sw
samer@3:     endif
samer@3:     return ind
samer@3: endfunction