" Vim indent file
" Language: Go
" Maintainer: David Barnett (https://github.com/google/vim-ft-go)
" Last Change: 2017 Jun 13
"
" TODO:
" - function invocations split across lines
" - general line splits (line ends in an operator)
if exists('b:did_indent')
finish
endif
let b:did_indent = 1
" C indentation is too far off useful, mainly due to Go's := operator.
" Let's just define our own.
setlocal nolisp
setlocal autoindent
setlocal indentexpr=GoIndent(v:lnum)
setlocal indentkeys+=<:>,0=},0=)
if exists('*GoIndent')
finish
endif
function! GoIndent(lnum)
let l:prevlnum = prevnonblank(a:lnum-1)
if l:prevlnum == 0
" top of file
return 0
endif
" grab the previous and current line, stripping comments.
let l:prevl = substitute(getline(l:prevlnum), '//.*$', '', '')
let l:thisl = substitute(getline(a:lnum), '//.*$', '', '')
let l:previ = indent(l:prevlnum)
let l:ind = l:previ
if l:prevl =~ '[({]\s*$'
" previous line opened a block
let l:ind += shiftwidth()
endif
if l:prevl =~# '^\s*\(case .*\|default\):$'
" previous line is part of a switch statement
let l:ind += shiftwidth()
endif
" TODO: handle if the previous line is a label.
if l:thisl =~ '^\s*[)}]'
" this line closed a block
let l:ind -= shiftwidth()
endif
" Colons are tricky.
" We want to outdent if it's part of a switch ("case foo:" or "default:").
" We ignore trying to deal with jump labels because (a) they're rare, and
" (b) they're hard to disambiguate from a composite literal key.
if l:thisl =~# '^\s*\(case .*\|default\):$'
let l:ind -= shiftwidth()
endif
return l:ind
endfunction
" vim: sw=2 sts=2 et
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