summaryrefslogtreecommitdiffstats
path: root/runtime/indent/erlang.vim
blob: 930f5d13254303c1c4da14af7ee14e96f4eea4df (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
" Vim indent file
" Language:     Erlang
" Author:       Csaba Hoch <csaba.hoch@gmail.com>
" Contributors: Edwin Fine <efine145_nospam01 at usa dot net>
"               Pawel 'kTT' Salata <rockplayer.pl@gmail.com>
"               Ricardo Catalinas Jiménez <jimenezrick@gmail.com>
" License:      Vim license
" Version:      2011/09/06

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

setlocal indentexpr=ErlangIndent()
setlocal indentkeys+==after,=end,=catch,=),=],=}

" Only define the functions once
if exists("*ErlangIndent")
    finish
endif

" The function goes through the whole line, analyses it and returns the
" indentation level.
"
" line: the line to be examined
" return: the indentation level of the examined line
function s:ErlangIndentAfterLine(line)
    let linelen = strlen(a:line) " the length of the line
    let i       = 0 " the index of the current character in the line
    let ind = 0 " how much should be the difference between the indentation of
                " the current line and the indentation of the next line?
                " e.g. +1: the indentation of the next line should be equal to
                " the indentation of the current line plus one shiftwidth
    let last_fun      = 0 " the last token was a 'fun'
    let last_receive  = 0 " the last token was a 'receive'; needed for 'after'
    let last_hash_sym = 0 " the last token was a '#'

    " Ignore comments
    if a:line =~# '^\s*%'
        return 0
    endif

    " Partial function head where the guard is missing
    if a:line =~# "\\(^\\l[[:alnum:]_]*\\)\\|\\(^'[^']\\+'\\)(" && a:line !~# '->'
        return 2
    endif

    " The missing guard from the split function head
    if a:line =~# '^\s*when\s\+.*->'
        return -1
    endif

    while 0<=i && i<linelen
        " m: the next value of the i
        if a:line[i] == '"'
            let m = matchend(a:line,'"\%([^"\\]\|\\.\)*"',i)
            let last_receive = 0
        elseif a:line[i] == "'"
            let m = matchend(a:line,"'[^']*'",i)
            let last_receive = 0
        elseif a:line[i] =~# "[a-z]"
            let m = matchend(a:line,".[[:alnum:]_]*",i)
            if last_fun
                let ind = ind - 1
                let last_fun = 0
                let last_receive = 0
            elseif a:line[(i):(m-1)] =~# '^\%(case\|if\|try\)$'
                let ind = ind + 1
            elseif a:line[(i):(m-1)] =~# '^receive$'
                let ind = ind + 1
                let last_receive = 1
            elseif a:line[(i):(m-1)] =~# '^begin$'
                let ind = ind + 2
                let last_receive = 0
            elseif a:line[(i):(m-1)] =~# '^end$'
                let ind = ind - 2
                let last_receive = 0
            elseif a:line[(i):(m-1)] =~# '^after$'
                if last_receive == 0
                    let ind = ind - 1
                else
                    let ind = ind + 0
                endif
                let last_receive = 0
            elseif a:line[(i):(m-1)] =~# '^fun$'
                let ind = ind + 1
                let last_fun = 1
                let last_receive = 0
            endif
        elseif a:line[i] =~# "[A-Z_]"
            let m = matchend(a:line,".[[:alnum:]_]*",i)
            let last_receive = 0
        elseif a:line[i] == '$'
            let m = i+2
            let last_receive = 0
        elseif a:line[i] == "." && (i+1>=linelen || a:line[i+1]!~ "[0-9]")
            let m = i+1
            if last_hash_sym
                let last_hash_sym = 0
            else
                let ind = ind - 1
            endif
            let last_receive = 0
        elseif a:line[i] == '-' && (i+1<linelen && a:line[i+1]=='>')
            let m = i+2
            let ind = ind + 1
            let last_receive = 0
        elseif a:line[i] == ';' && a:line[(i):(linelen)] !~# '.*->.*'
            let m = i+1
            let ind = ind - 1
            let last_receive = 0
        elseif a:line[i] == '#'
            let m = i+1
            let last_hash_sym = 1
        elseif a:line[i] =~# '[({[]'
            let m = i+1
            let ind = ind + 1
            let last_fun = 0
            let last_receive = 0
            let last_hash_sym = 0
        elseif a:line[i] =~# '[)}\]]'
            let m = i+1
            let ind = ind - 1
            let last_receive = 0
        else
            let m = i+1
        endif

        let i = m
    endwhile

    return ind
endfunction

function s:FindPrevNonBlankNonComment(lnum)
    let lnum = prevnonblank(a:lnum)
    let line = getline(lnum)
    " Continue to search above if the current line begins with a '%'
    while line =~# '^\s*%.*$'
        let lnum = prevnonblank(lnum - 1)
        if 0 == lnum
            return 0
        endif
        let line = getline(lnum)
    endwhile
    return lnum
endfunction

" The function returns the indentation level of the line adjusted to a mutiple
" of 'shiftwidth' option.
"
" lnum: line number
" return: the indentation level of the line
function s:GetLineIndent(lnum)
    return (indent(a:lnum) / &sw) * &sw
endfunction

function ErlangIndent()
    " Find a non-blank line above the current line
    let lnum = prevnonblank(v:lnum - 1)

    " Hit the start of the file, use zero indent
    if lnum == 0
        return 0
    endif

    let prevline = getline(lnum)
    let currline = getline(v:lnum)

    let ind_after = s:ErlangIndentAfterLine(prevline)
    if ind_after != 0
        let ind = s:GetLineIndent(lnum) + ind_after * &sw
    else
        let ind = indent(lnum) + ind_after * &sw
    endif

    " Special cases:
    if prevline =~# '^\s*\%(after\|end\)\>'
        let ind = ind + 2*&sw
    endif
    if currline =~# '^\s*end\>'
        let ind = ind - 2*&sw
    endif
    if currline =~# '^\s*after\>'
        let plnum = s:FindPrevNonBlankNonComment(v:lnum-1)
        if getline(plnum) =~# '^[^%]*\<receive\>\s*\%(%.*\)\=$'
            " If the 'receive' is not in the same line as the 'after'
            let ind = ind - 1*&sw
        else
            let ind = ind - 2*&sw
        endif
    endif
    if prevline =~# '^\s*[)}\]]'
        let ind = ind + 1*&sw
    endif
    if currline =~# '^\s*[)}\]]'
        let ind = ind - 1*&sw
    endif
    if prevline =~# '^\s*\%(catch\)\s*\%(%\|$\)'
        let ind = ind + 1*&sw
    endif
    if currline =~# '^\s*\%(catch\)\s*\%(%\|$\)'
        let ind = ind - 1*&sw
    endif

    if ind<0
        let ind = 0
    endif
    return ind
endfunction