" Vim indent file
" Language: occam
" Maintainer: Mario Schweigler <[email protected]>
" Last Change: 23 April 2003

" Only load this indent file when no other was loaded.
if exists("b:did_indent")
finish
endif
let b:did_indent = 1

"{{{ Settings
" Set the occam indent function
setlocal indentexpr=GetOccamIndent()
" Indent after new line and after initial colon
setlocal indentkeys=o,O,0=:
"}}}

" Only define the function once
if exists("*GetOccamIndent")
finish
endif
let s:keepcpo= &cpo
set cpo&vim

"{{{ Indent definitions
" Define carriage return indent
let s:FirstLevelIndent = '^\C\s*\(IF\|ALT\|PRI\s\+ALT\|PAR\|SEQ\|PRI\s\+PAR\|WHILE\|VALOF\|CLAIM\|FORKING\)\>\|\(--.*\)\@<!\(\<PROC\>\|??\|\<CASE\>\s*\(--.*\)\=\_$\)'
let s:FirstLevelNonColonEndIndent = '^\C\s*PROTOCOL\>\|\(--.*\)\@<!\<\(\(CHAN\|DATA\)\s\+TYPE\|FUNCTION\)\>'
let s:SecondLevelIndent = '^\C\s*\(IF\|ALT\|PRI\s\+ALT\)\>\|\(--.*\)\@<!?\s*\<CASE\>\s*\(--.*\)\=\_$'
let s:SecondLevelNonColonEndIndent = '\(--.*\)\@<!\<\(CHAN\|DATA\)\s\+TYPE\>'

" Define colon indent
let s:ColonIndent = '\(--.*\)\@<!\<PROC\>'
let s:ColonNonColonEndIndent = '^\C\s*PROTOCOL\>\|\(--.*\)\@<!\<\(\(CHAN\|DATA\)\s\+TYPE\|FUNCTION\)\>'

let s:ColonEnd = '\(--.*\)\@<!:\s*\(--.*\)\=$'
let s:ColonStart = '^\s*:\s*\(--.*\)\=$'

" Define comment
let s:CommentLine = '^\s*--'
"}}}

"{{{ function GetOccamIndent()
" Auxiliary function to get the correct indent for a line of occam code
function GetOccamIndent()

" Ensure magic is on
let save_magic = &magic
setlocal magic

" Get reference line number
let linenum = prevnonblank(v:lnum - 1)
while linenum > 0 && getline(linenum) =~ s:CommentLine
let linenum = prevnonblank(linenum - 1)
endwhile

" Get current indent
let curindent = indent(linenum)

" Get current line
let line = getline(linenum)

" Get previous line number
let prevlinenum = prevnonblank(linenum - 1)
while prevlinenum > 0 && getline(prevlinenum) =~ s:CommentLine
let prevlinenum = prevnonblank(prevlinenum - 1)
endwhile

" Get previous line
let prevline = getline(prevlinenum)

" Colon indent
if getline(v:lnum) =~ s:ColonStart

let found = 0

while found < 1

if line =~ s:ColonStart
let found = found - 1
elseif line =~ s:ColonIndent || (line =~ s:ColonNonColonEndIndent && line !~ s:ColonEnd)
let found = found + 1
endif

if found < 1
let linenum = prevnonblank(linenum - 1)
if linenum > 0
let line = getline(linenum)
else
let found = 1
endif
endif

endwhile

if linenum > 0
let curindent = indent(linenum)
else
let colonline = getline(v:lnum)
let tabstr = ''
while strlen(tabstr) < &tabstop
let tabstr = ' ' . tabstr
endwhile
let colonline = substitute(colonline, '\t', tabstr, 'g')
let curindent = match(colonline, ':')
endif

" Restore magic
if !save_magic|setlocal nomagic|endif

return curindent
endif

if getline(v:lnum) =~ '^\s*:'
let colonline = getline(v:lnum)
let tabstr = ''
while strlen(tabstr) < &tabstop
let tabstr = ' ' . tabstr
endwhile
let colonline = substitute(colonline, '\t', tabstr, 'g')
let curindent = match(colonline, ':')

" Restore magic
if !save_magic|setlocal nomagic|endif

return curindent
endif

" Carriage return indenat
if line =~ s:FirstLevelIndent || (line =~ s:FirstLevelNonColonEndIndent && line !~ s:ColonEnd)
\ || (line !~ s:ColonStart && (prevline =~ s:SecondLevelIndent
\ || (prevline =~ s:SecondLevelNonColonEndIndent && prevline !~ s:ColonEnd)))
let curindent = curindent + &shiftwidth

" Restore magic
if !save_magic|setlocal nomagic|endif

return curindent
endif

" Commented line
if getline(prevnonblank(v:lnum - 1)) =~ s:CommentLine

" Restore magic
if !save_magic|setlocal nomagic|endif

return indent(prevnonblank(v:lnum - 1))
endif

" Look for previous second level IF / ALT / PRI ALT
let found = 0

while !found

if indent(prevlinenum) == curindent - &shiftwidth
let found = 1
endif

if !found
let prevlinenum = prevnonblank(prevlinenum - 1)
while prevlinenum > 0 && getline(prevlinenum) =~ s:CommentLine
let prevlinenum = prevnonblank(prevlinenum - 1)
endwhile
if prevlinenum == 0
let found = 1
endif
endif

endwhile

if prevlinenum > 0
if getline(prevlinenum) =~ s:SecondLevelIndent
let curindent = curindent + &shiftwidth
endif
endif

" Restore magic
if !save_magic|setlocal nomagic|endif

return curindent

endfunction
"}}}

let &cpo = s:keepcpo
unlet s:keepcpo