xref: /vim-8.2.3635/runtime/indent/fortran.vim (revision e0e39175)
1" Vim indent file
2" Language:	Fortran 2008 (and older: Fortran 2003, 95, 90, and 77)
3" Version:	(v48) 2020 October 07
4" Maintainer:	Ajit J. Thakkar <[email protected]>; <http://www2.unb.ca/~ajit/>
5" Usage:	For instructions, do :help fortran-indent from Vim
6" Credits:
7"  Version 0.1 was created in September 2000 by Ajit Thakkar.
8"  Since then, useful suggestions and contributions have been made, in order, by:
9"  Albert Oliver Serra, Takuya Fujiwara, Philipp Edelmann, Eisuke Kawashima,
10"  and Louis Cochen.
11
12" Only load this indent file when no other was loaded.
13if exists("b:did_indent")
14  finish
15endif
16let b:did_indent = 1
17
18let s:cposet=&cpoptions
19set cpoptions&vim
20
21setlocal indentkeys+==~end,=~case,=~if,=~else,=~do,=~where,=~elsewhere,=~select
22setlocal indentkeys+==~endif,=~enddo,=~endwhere,=~endselect,=~elseif
23setlocal indentkeys+==~type,=~interface,=~forall,=~associate,=~block,=~enum
24setlocal indentkeys+==~endforall,=~endassociate,=~endblock,=~endenum
25if exists("b:fortran_indent_more") || exists("g:fortran_indent_more")
26  setlocal indentkeys+==~function,=~subroutine,=~module,=~contains,=~program
27  setlocal indentkeys+==~endfunction,=~endsubroutine,=~endmodule
28  setlocal indentkeys+==~endprogram
29endif
30
31" Determine whether this is a fixed or free format source file
32" if this hasn't been done yet using the priority:
33" buffer-local value
34" > global value
35" > file extension as in Intel ifort, gcc (gfortran), NAG, Pathscale, and Cray compilers
36if !exists("b:fortran_fixed_source")
37  if exists("fortran_free_source")
38    " User guarantees free source form
39    let b:fortran_fixed_source = 0
40  elseif exists("fortran_fixed_source")
41    " User guarantees fixed source form
42    let b:fortran_fixed_source = 1
43  elseif expand("%:e") =~? '^f\%(90\|95\|03\|08\)$'
44    " Free-form file extension defaults as in Intel ifort, gcc(gfortran), NAG, Pathscale, and Cray compilers
45    let b:fortran_fixed_source = 0
46  elseif expand("%:e") =~? '^\%(f\|f77\|for\)$'
47    " Fixed-form file extension defaults
48    let b:fortran_fixed_source = 1
49  else
50    " Modern fortran still allows both fixed and free source form
51    " Assume fixed source form unless signs of free source form
52    " are detected in the first five columns of the first s:lmax lines.
53    " Detection becomes more accurate and time-consuming if more lines
54    " are checked. Increase the limit below if you keep lots of comments at
55    " the very top of each file and you have a fast computer.
56    let s:lmax = 500
57    if ( s:lmax > line("$") )
58      let s:lmax = line("$")
59    endif
60    let b:fortran_fixed_source = 1
61    let s:ln=1
62    while s:ln <= s:lmax
63      let s:test = strpart(getline(s:ln),0,5)
64      if s:test !~ '^[Cc*]' && s:test !~ '^ *[!#]' && s:test =~ '[^ 0-9\t]' && s:test !~ '^[ 0-9]*\t'
65	let b:fortran_fixed_source = 0
66	break
67      endif
68      let s:ln = s:ln + 1
69    endwhile
70  endif
71endif
72
73" Define the appropriate indent function but only once
74if (b:fortran_fixed_source == 1)
75  setlocal indentexpr=FortranGetFixedIndent()
76  if exists("*FortranGetFixedIndent")
77    let &cpoptions = s:cposet
78    unlet s:cposet
79    finish
80  endif
81else
82  setlocal indentexpr=FortranGetFreeIndent()
83  if exists("*FortranGetFreeIndent")
84    let &cpoptions = s:cposet
85    unlet s:cposet
86    finish
87  endif
88endif
89
90function FortranGetIndent(lnum)
91  let ind = indent(a:lnum)
92  let prevline=getline(a:lnum)
93  " Strip tail comment
94  let prevstat=substitute(prevline, '!.*$', '', '')
95  let prev2line=getline(a:lnum-1)
96  let prev2stat=substitute(prev2line, '!.*$', '', '')
97
98  "Indent do loops only if they are all guaranteed to be of do/end do type
99  if exists("b:fortran_do_enddo") || exists("g:fortran_do_enddo")
100    if prevstat =~? '^\s*\(\d\+\s\)\=\s*\(\a\w*\s*:\)\=\s*do\>'
101      let ind = ind + shiftwidth()
102    endif
103    if getline(v:lnum) =~? '^\s*\(\d\+\s\)\=\s*end\s*do\>'
104      let ind = ind - shiftwidth()
105    endif
106  endif
107
108  "Add a shiftwidth to statements following if, else, else if, case, class,
109  "where, else where, forall, type, interface and associate statements
110  if prevstat =~? '^\s*\(case\|class\|else\|else\s*if\|else\s*where\)\>'
111	\ ||prevstat=~? '^\s*\(type\|interface\|associate\|enum\)\>'
112	\ ||prevstat=~?'^\s*\(\d\+\s\)\=\s*\(\a\w*\s*:\)\=\s*\(forall\|where\|block\)\>'
113	\ ||prevstat=~? '^\s*\(\d\+\s\)\=\s*\(\a\w*\s*:\)\=\s*if\>'
114     let ind = ind + shiftwidth()
115    " Remove unwanted indent after logical and arithmetic ifs
116    if prevstat =~? '\<if\>' && prevstat !~? '\<then\>'
117      let ind = ind - shiftwidth()
118    endif
119    " Remove unwanted indent after type( statements
120    if prevstat =~? '^\s*type\s*('
121      let ind = ind - shiftwidth()
122    endif
123  endif
124
125  "Indent program units unless instructed otherwise
126  if !exists("b:fortran_indent_less") && !exists("g:fortran_indent_less")
127    let prefix='\(\(pure\|impure\|elemental\|recursive\)\s\+\)\{,2}'
128    let type='\(\(integer\|real\|double\s\+precision\|complex\|logical'
129          \.'\|character\|type\|class\)\s*\S*\s\+\)\='
130    if prevstat =~? '^\s*\(contains\|submodule\|program\)\>'
131            \ ||prevstat =~? '^\s*'.'module\>\(\s*\procedure\)\@!'
132            \ ||prevstat =~? '^\s*'.prefix.'subroutine\>'
133            \ ||prevstat =~? '^\s*'.prefix.type.'function\>'
134            \ ||prevstat =~? '^\s*'.type.prefix.'function\>'
135      let ind = ind + shiftwidth()
136    endif
137    if getline(v:lnum) =~? '^\s*contains\>'
138          \ ||getline(v:lnum)=~? '^\s*end\s*'
139          \ .'\(function\|subroutine\|module\|submodule\|program\)\>'
140      let ind = ind - shiftwidth()
141    endif
142  endif
143
144  "Subtract a shiftwidth from else, else if, elsewhere, case, class, end if,
145  " end where, end select, end forall, end interface, end associate,
146  " end enum, end type, end block and end type statements
147  if getline(v:lnum) =~? '^\s*\(\d\+\s\)\=\s*'
148        \. '\(else\|else\s*if\|else\s*where\|case\|class\|'
149        \. 'end\s*\(if\|where\|select\|interface\|'
150        \. 'type\|forall\|associate\|enum\|block\)\)\>'
151    let ind = ind - shiftwidth()
152    " Fix indent for case statement immediately after select
153    if prevstat =~? '\<select\s*\(case\|type\)\>'
154      let ind = ind + shiftwidth()
155    endif
156  endif
157
158  "First continuation line
159  if prevstat =~ '&\s*$' && prev2stat !~ '&\s*$'
160    let ind = ind + shiftwidth()
161  endif
162  "Line after last continuation line
163  if prevstat !~ '&\s*$' && prev2stat =~ '&\s*$' && prevstat !~? '\<then\>'
164    let ind = ind - shiftwidth()
165  endif
166
167  return ind
168endfunction
169
170function FortranGetFreeIndent()
171  "Find the previous non-blank line
172  let lnum = prevnonblank(v:lnum - 1)
173
174  "Use zero indent at the top of the file
175  if lnum == 0
176    return 0
177  endif
178
179  let ind=FortranGetIndent(lnum)
180  return ind
181endfunction
182
183function FortranGetFixedIndent()
184  let currline=getline(v:lnum)
185  "Don't indent comments, continuation lines and labelled lines
186  if strpart(currline,0,6) =~ '[^ \t]'
187    let ind = indent(v:lnum)
188    return ind
189  endif
190
191  "Find the previous line which is not blank, not a comment,
192  "not a continuation line, and does not have a label
193  let lnum = v:lnum - 1
194  while lnum > 0
195    let prevline=getline(lnum)
196    if (prevline =~ "^[C*!]") || (prevline =~ "^\s*$")
197	\ || (strpart(prevline,5,1) !~ "[ 0]")
198      " Skip comments, blank lines and continuation lines
199      let lnum = lnum - 1
200    else
201      let test=strpart(prevline,0,5)
202      if test =~ "[0-9]"
203	" Skip lines with statement numbers
204	let lnum = lnum - 1
205      else
206	break
207      endif
208    endif
209  endwhile
210
211  "First line must begin at column 7
212  if lnum == 0
213    return 6
214  endif
215
216  let ind=FortranGetIndent(lnum)
217  return ind
218endfunction
219
220let &cpoptions = s:cposet
221unlet s:cposet
222
223" vim:sw=2 tw=130
224