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Improve space-based shiftwidth detection #16

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Improve space-based shiftwidth detection #16

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eb51238
Count leading tab and space
czchen Oct 11, 2012
a0e20a6
Use leading tab & space count to determine indent style
czchen Oct 11, 2012
c2ff549
Add .h files to C-style comment detection
aclindsa Dec 5, 2012
fd89a72
Make leading_space_count a local variable
aclindsa Dec 5, 2012
8924eaa
Set shiftwidth based on the GCD of the most common tab spacings.
aclindsa Dec 5, 2012
736b001
Bail out if we detect a version of vim < 7
aclindsa Nov 15, 2013
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96 changes: 49 additions & 47 deletions plugin/detectindent.vim
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,12 @@
" " impossible:
" :let g:detectindent_preferred_indent = 4
"
" Requirements: Untested on Vim versions below 6.2
" Requirements: Does not work on Vim versions below 7.0

" Bail out if we're on an old version of vim
if version < 700
finish
endif

if exists("loaded_detectindent")
finish
Expand All @@ -29,7 +34,7 @@ if !exists('g:detectindent_verbosity')
endif

fun! <SID>HasCStyleComments()
return index(["c", "cpp", "java", "javascript", "php"], &ft) != -1
return index(["c", "cpp", "h", "java", "javascript", "php"], &ft) != -1
endfun

fun! <SID>IsCommentStart(line)
Expand All @@ -45,12 +50,22 @@ fun! <SID>IsCommentLine(line)
return <SID>HasCStyleComments() && a:line =~ '^\s\+//'
endfun

fun! <SID>GCD(x, y)
let l:a = a:x
let l:b = a:y
while l:b > 0
let l:temp = l:b
let l:b = l:a % l:b
let l:a = l:temp
endwhile
return l:a
endfun

fun! <SID>DetectIndent()
let l:has_leading_tabs = 0
let l:has_leading_spaces = 0
let l:shortest_leading_spaces_run = 0
let l:shortest_leading_spaces_idx = 0
let l:longest_leading_spaces_run = 0
let l:leading_tab_count = 0
let l:leading_space_count = 0
let l:leading_space_dict = {}
let l:leading_spaces_gcd = 0
let l:max_lines = 1024
if exists("g:detectindent_max_lines_to_analyse")
let l:max_lines = g:detectindent_max_lines_to_analyse
Expand Down Expand Up @@ -94,22 +109,15 @@ fun! <SID>DetectIndent()
let l:leading_char = strpart(l:line, 0, 1)

if l:leading_char == "\t"
let l:has_leading_tabs = 1
let l:leading_tab_count = l:leading_tab_count + 1

elseif l:leading_char == " "
" only interested if we don't have a run of spaces followed by a
" tab.
if -1 == match(l:line, '^ \+\t')
let l:has_leading_spaces = 1
let l:leading_space_count = l:leading_space_count + 1
let l:spaces = strlen(matchstr(l:line, '^ \+'))
if l:shortest_leading_spaces_run == 0 ||
\ l:spaces < l:shortest_leading_spaces_run
let l:shortest_leading_spaces_run = l:spaces
let l:shortest_leading_spaces_idx = l:idx
endif
if l:spaces > l:longest_leading_spaces_run
let l:longest_leading_spaces_run = l:spaces
endif
let l:leading_space_dict[l:spaces] = get(l:leading_space_dict, l:spaces) + 1
endif

endif
Expand All @@ -124,40 +132,36 @@ fun! <SID>DetectIndent()

endwhile

if l:has_leading_tabs && ! l:has_leading_spaces
" tabs only, no spaces
let l:verbose_msg = "Detected tabs only and no spaces"
if l:leading_tab_count > l:leading_space_count
let l:verbose_msg = "Use tab to indent."
setl noexpandtab
if exists("g:detectindent_preferred_indent")
let &l:shiftwidth = g:detectindent_preferred_indent
let &l:tabstop = g:detectindent_preferred_indent
endif

elseif l:has_leading_spaces && ! l:has_leading_tabs
" spaces only, no tabs
let l:verbose_msg = "Detected spaces only and no tabs"
setl expandtab
let &l:shiftwidth = l:shortest_leading_spaces_run
let &l:softtabstop = l:shortest_leading_spaces_run

elseif l:has_leading_spaces && l:has_leading_tabs
" spaces and tabs
let l:verbose_msg = "Detected spaces and tabs"
setl noexpandtab
let &l:shiftwidth = l:shortest_leading_spaces_run
elseif l:leading_space_count > l:leading_tab_count
" Filter out those tab stops which occurred in < 10% of the lines
call filter(l:leading_space_dict, '100*v:val/l:leading_space_count >= 10')

" Find the greatest common divisor of the remaining tab stop lengths
let l:leading_spaces_gcd = 0
for length in keys(l:leading_space_dict)
if l:leading_spaces_gcd == 0
let l:leading_spaces_gcd = length
else
let l:leading_spaces_gcd = <SID>GCD(length, l:leading_spaces_gcd)
endif
endfor

" mmmm, time to guess how big tabs are
if l:longest_leading_spaces_run <= 2
let &l:tabstop = 2
elseif l:longest_leading_spaces_run <= 4
let &l:tabstop = 4
else
let &l:tabstop = 8
if l:leading_spaces_gcd != 0
let l:verbose_msg = "Use space to indent."
setl expandtab
let &l:shiftwidth = l:leading_spaces_gcd
let &l:softtabstop = l:leading_spaces_gcd
endif

else
" no spaces, no tabs
let l:verbose_msg = "Detected no spaces and no tabs"
let l:verbose_msg = "Cannot determine indent. Use default to indent."
if exists("g:detectindent_preferred_indent") &&
\ exists("g:detectindent_preferred_expandtab")
setl expandtab
Expand All @@ -177,11 +181,9 @@ fun! <SID>DetectIndent()

if &verbose >= g:detectindent_verbosity
echo l:verbose_msg
\ ."; has_leading_tabs:" l:has_leading_tabs
\ .", has_leading_spaces:" l:has_leading_spaces
\ .", shortest_leading_spaces_run:" l:shortest_leading_spaces_run
\ .", shortest_leading_spaces_idx:" l:shortest_leading_spaces_idx
\ .", longest_leading_spaces_run:" l:longest_leading_spaces_run
\ ."; leading_tab_count:" l:leading_tab_count
\ .", leading_space_count:" l:leading_space_count
\ .", leading_spaces_gcd:" l:leading_spaces_gcd

let changed_msg = []
for [setting, oldval] in items(b:detectindent_cursettings)
Expand Down