" vim: set sw=3 sts=3:
" Awk indent script. It can handle multi-line statements and expressions.
" It works up to the point where the distinction between correct/incorrect
" and personal taste gets fuzzy. Drop me an e-mail for bug reports and
" reasonable style suggestions.
"
" Bugs:
" =====
" - Some syntax errors may cause erratic indentation.
" - Same for very unusual but syntacticly correct use of { }
" - In some cases it's confused by the use of ( and { in strings constants
" - This version likes the closing brace of a multiline pattern-action be on
" character position 1 before the following pattern-action combination is
" formatted
" Author:
" =======
" Erik Janssen, ejanssen@itmatters.nl
"
" History:
" ========
" 26-04-2002 Got initial version working reasonably well
" 29-04-2002 Fixed problems in function headers and max line width
" Added support for two-line if's without curly braces
" Fixed hang: 2011 Aug 31
" Only load this indent file when no other was loaded.
if exists("b:did_indent")
finish
endif
let b:did_indent = 1
setlocal indentexpr=GetAwkIndent()
" Mmm, copied from the tcl indent program. Is this okay?
setlocal indentkeys-=:,0#
" Only define the function once.
if exists("*GetAwkIndent")
finish
endif
" This function contains a lot of exit points. It checks for simple cases
" first to get out of the function as soon as possible, thereby reducing the
" number of possibilities later on in the difficult parts
function! GetAwkIndent()
" Find previous line and get it's indentation
let prev_lineno = s:Get_prev_line( v:lnum )
if prev_lineno == 0
return 0
endif
let prev_data = getline( prev_lineno )
let ind = indent( prev_lineno )
" Increase indent if the previous line contains an opening brace. Search
" for this brace the hard way to prevent errors if the previous line is a
" 'pattern { action }' (simple check match on /{/ increases the indent then)
if s:Get_brace_balance( prev_data, '{', '}' ) > 0
return ind + shiftwidth()
endif
let brace_balance = s:Get_brace_balance( prev_data, '(', ')' )
" If prev line has positive brace_balance and starts with a word (keyword
" or function name), align the current line on the first '(' of the prev
" line
if brace_balance > 0 && s:Starts_with_word( prev_data )
return s:Safe_indent( ind, s:First_word_len(prev_data), getline(v:lnum))
endif
" If this line starts with an open brace bail out now before the line
" continuation checks.
if getline( v:lnum ) =~ '^\s*{'
return ind
endif
" If prev line seems to be part of multiline statement:
" 1. Prev line is first line of a multiline statement
" -> attempt to indent on first ' ' or '(' of prev line, just like we
" indented the positive brace balance case above
" 2. Prev line is not first line of a multiline statement
" -> copy indent of prev line
let continue_mode = s:Seems_continuing( prev_data )
if continue_mode > 0
if s:Seems_continuing( getline(s:Get_prev_line( prev_lineno )) )
" Case 2
return ind
else
" Case 1
if continue_mode == 1
" Need continuation due to comma, backslash, etc
return s:Safe_indent( ind, s:First_word_len(prev_data), getline(v:lnum))
else
" if/for/while without '{'
return ind + shiftwidth()
endif
endif
endif
" If the previous line doesn't need continuation on the current line we are
" on the start of a new statement. We have to make sure we align with the
" previous statement instead of just the previous line. This is a bit
" complicated because the previous statement might be multi-line.
"
" The start of a multiline statement can be found by:
"
" 1 If the previous line contains closing braces and has negative brace
" balance, search backwards until cumulative brace balance becomes zero,
" take indent of that line
" 2 If the line before the previous needs continuation search backward
" until that's not the case anymore. Take indent of one line down.
" Case 1
if prev_data =~ ')' && brace_balance < 0
while brace_balance != 0 && prev_lineno > 0
let prev_lineno = s:Get_prev_line( prev_lineno )
let prev_data = getline( prev_lineno )
let brace_balance=brace_balance+s:Get_brace_balance(prev_data,'(',')' )
endwhile
let ind = indent( prev_lineno )
else
" Case 2
if s:Seems_continuing( getline( prev_lineno - 1 ) )
let prev_lineno = prev_lineno - 2
let prev_data = getline( prev_lineno )
while prev_lineno > 0 && (s:Seems_continuing( prev_data ) > 0)
let prev_lineno = s:Get_prev_line( prev_lineno )
let prev_data = getline( prev_lineno )
endwhile
let ind = indent( prev_lineno + 1 )
endif
endif
" Decrease indent if this line contains a '}'.
if getline(v:lnum) =~ '^\s*}'
let ind = ind - shiftwidth()
endif
return ind
endfunction
" Find the open and close braces in this line and return how many more open-
" than close braces there are. It's also used to determine cumulative balance
" across multiple lines.
function! s:Get_brace_balance( line, b_open, b_close )
let line2 = substitute( a:line, a:b_open, "", "g" )
let openb = strlen( a:line ) - strlen( line2 )
let line3 = substitute( line2, a:b_close, "", "g" )
let closeb = strlen( line2 ) - strlen( line3 )
return openb - closeb
endfunction
" Find out whether the line starts with a word (i.e. keyword or function
" call). Might need enhancements here.
function! s:Starts_with_word( line )
if a:line =~ '^\s*[a-zA-Z_0-9]\+\s*('
return 1
endif
return 0
endfunction
" Find the length of the first word in a line. This is used to be able to
" align a line relative to the 'print ' or 'if (' on the previous line in case
" such a statement spans multiple lines.
" Precondition: only to be used on lines where 'Starts_with_word' returns 1.
function! s:First_word_len( line )
let white_end = matchend( a:line, '^\s*' )
if match( a:line, '^\s*func' ) != -1
let word_end = matchend( a:line, '[a-z]\+\s\+[a-zA-Z_0-9]\+[ (]*' )
else
let word_end = matchend( a:line, '[a-zA-Z_0-9]\+[ (]*' )
endif
return word_end - white_end
endfunction
" Determine if 'line' completes a statement or is continued on the next line.
" This one is far from complete and accepts illegal code. Not important for
" indenting, however.
function! s:Seems_continuing( line )
" Unfinished lines
if a:line =~ '\(--\|++\)\s*$'
return 0
endif
if a:line =~ '[\\,\|\&\+\-\*\%\^]\s*$'
return 1
endif
" if/for/while (cond) eol
if a:line =~ '^\s*\(if\|while\|for\)\s*(.*)\s*$' || a:line =~ '^\s*else\s*'
return 2
endif
return 0
endfunction
" Get previous relevant line. Search back until a line is that is no
" comment or blank and return the line number
function! s:Get_prev_line( lineno )
let lnum = a:lineno - 1
let data = getline( lnum )
while lnum > 0 && (data =~ '^\s*#' || data =~ '^\s*$')
let lnum = lnum - 1
let data = getline( lnum )
endwhile
return lnum
endfunction
" This function checks whether an indented line exceeds a maximum linewidth
" (hardcoded 80). If so and it is possible to stay within 80 positions (or
" limit num of characters beyond linewidth) by decreasing the indent (keeping
" it > base_indent), do so.
function! s:Safe_indent( base, wordlen, this_line )
let line_base = matchend( a:this_line, '^\s*' )
let line_len = strlen( a:this_line ) - line_base
let indent = a:base
if (indent + a:wordlen + line_len) > 80
" Simple implementation good enough for the time being
let indent = indent + 3
endif
return indent + a:wordlen
endfunction
