walker.lua

   1 local M = {}
   2
   3 local function finishof(node) return node.finish end
   4 local function startof(node) return node.start end
   5 local function is_comment(node) return node.is_comment end
   6
   7 function M.new(parser, eol_at, bol_at)
   8
   9         local function in_quasilist(t, range)
  10                 return t and t.d and not t.is_list and
  11                         range.start >= t.start + #t.d and range.finish <= t.finish + 1 - #parser.opposite[t.d]
  12         end
  13
  14         local function sexp_at(range, true_sexp)
  15                 local node, parent, nth = parser.tree.sexp_at(range)
  16                 if not in_quasilist(node, range) or true_sexp then
  17                         return node, parent, nth
  18                 else
  19                         return node.word_at(range), node
  20                 end
  21         end
  22
  23         local function find_before_innermost(t, range, key, pred)
  24                 if t.is_root or (t.d and t.start < range.start) then
  25                         if t.d and not t.is_list then
  26                                 local keypos = key(t)
  27                                 local start = keypos == startof(t)
  28                                 local finish = keypos == finishof(t)
  29                                 local newpos
  30                                 if finish then
  31                                         newpos = t.finish_before(range.finish)
  32                                 elseif start then
  33                                         newpos = t.start_before(range.start)
  34                                 end
  35                                 if newpos then
  36                                         local word = t.word_at({start = newpos, finish = newpos})
  37                                         if word and pred(word) then
  38                                                 return word
  39                                         end
  40                                 end
  41                                 return
  42                         end
  43                         local _, nearest_n = t.before(range.start, startof)
  44                         if nearest_n then
  45                                 for n = nearest_n, 1, -1 do
  46                                         local child = t[n]
  47                                         if child.d and not child.is_empty then
  48                                                 local ret = find_before_innermost(child, range, key, pred)
  49                                                 if ret then
  50                                                         return ret
  51                                                 end
  52                                         elseif key(child) < key(range) and pred(child, n, #t) then
  53                                                 return child, n, #t
  54                                         end
  55                                 end
  56                         end
  57                         if not t.is_root and pred(t) then
  58                                 return t
  59                         end
  60                 end
  61         end
  62
  63         local function find_after_innermost(t, range, key, pred)
  64                 if t.is_root or (t.d and t.finish >= range.finish) then
  65                         if t.d and not t.is_list then
  66                                 local keypos = key(t)
  67                                 local start = keypos == startof(t)
  68                                 local finish = keypos == finishof(t)
  69                                 local newpos
  70                                 if finish then
  71                                         newpos = t.finish_after(math.max(t.start + #t.d, range.finish))
  72                                 elseif start then
  73                                         newpos = range.finish < t.start and t.start + #t.d or t.start_after(range.start)
  74                                 end
  75                                 if newpos then
  76                                         local word = t.word_at({start = newpos, finish = newpos})
  77                                         if word and pred(word) then
  78                                                 return word
  79                                         end
  80                                 end
  81                                 return
  82                         end
  83                         local _, nearest_n = t.after(range.finish, finishof)
  84                         if nearest_n then
  85                                 for n = nearest_n, #t do
  86                                         local child = t[n]
  87                                         if child.d and not child.is_empty then
  88                                                 local ret = find_after_innermost(child, range, key, pred)
  89                                                 if ret then
  90                                                         return ret
  91                                                 end
  92                                         elseif key(child) >= key(range) and pred(child, n, #t) then
  93                                                 return child, n, #t
  94                                         end
  95                                 end
  96                         end
  97                         if not t.is_root and pred(t) then
  98                                 return t
  99                         end
 100                 end
 101         end
 102
 103         return {
 104
 105                 start_before = function(range, skip)
 106                         local _, parent = parser.tree.sexp_at(range)
 107                         local node = parent.before(range.start, startof, skip)
 108                         return node and startof(node)
 109                 end,
 110
 111                 start_after = function(range, skip)
 112                         local _, parent = parser.tree.sexp_at(range)
 113                         local node = parent.after(range.finish, startof, skip)
 114                         return node and startof(node)
 115                 end,
 116
 117                 finish_before = function(range, skip)
 118                         local _, parent = parser.tree.sexp_at(range)
 119                         local node = parent.before(range.start, finishof, skip)
 120                         return node and finishof(node) + 1
 121                 end,
 122
 123                 finish_after = function(range, skip)
 124                         local _, parent = parser.tree.sexp_at(range)
 125                         local node = parent.after(range.finish, finishof, skip)
 126                         return node and finishof(node) + 1
 127                 end,
 128
 129                 start_down_after = function(range, skip)
 130                         local node, parent = parser.tree.sexp_at(range)
 131                         if in_quasilist(node, range) then return end
 132                         if node and node.p then
 133                                 -- XXX: if we are past a prefix start, this will prevent skipping over its list
 134                                 range.start = node.start
 135                         end
 136                         local next_list = parent.find_after(range, function(t) return t.is_list end)
 137                         if next_list then
 138                                 local first = next_list.after(range.finish, startof, skip)
 139                                 if first then
 140                                         return first.start
 141                                 else
 142                                         return next_list.start + (next_list.p and #next_list.p or 0) + 1
 143                                 end
 144                         end
 145                 end,
 146
 147                 start_up_before = function(range)
 148                         local _, parent = sexp_at(range)
 149                         return parent.d and parent.start
 150                 end,
 151
 152                 finish_down_before = function(range, skip)
 153                         local node, parent = parser.tree.sexp_at(range)
 154                         if in_quasilist(node, range) then return end
 155                         local prev_list = parent.find_before(range, function(t) return t.is_list end)
 156                         if prev_list then
 157                                 local last = prev_list.before(range.start, finishof, skip)
 158                                 if last then
 159                                         return (last.finish or last.p and last.start + #last.p) + 1, prev_list
 160                                 else
 161                                         return prev_list.finish, prev_list
 162                                 end
 163                         end
 164                 end,
 165
 166                 finish_up_after = function(range)
 167                         local _, parent = sexp_at(range)
 168                         return parent.d and parent.finish + 1
 169                 end,
 170
 171                 indented_before = function(range)
 172                         return find_before_innermost(parser.tree, range, startof, function(t) return t.indent end)
 173                 end,
 174
 175                 start_float_before = function(range, up_empty_list)
 176                         if up_empty_list then
 177                                 local _, parent = sexp_at(range)
 178                                 if parent.is_empty then
 179                                         return parent.start, parent
 180                                 end
 181                         end
 182                         local node = find_before_innermost(parser.tree, range, startof, function(t, n, _)
 183                                 return not t.d or t.is_empty and n == 1 end)
 184                         return node and node.start, node
 185                 end,
 186
 187                 start_float_after = function(range, up_empty_list)
 188                         if up_empty_list then
 189                                 local _, parent = sexp_at(range)
 190                                 if parent.is_empty then
 191                                         return parent.finish + 1, parent
 192                                 end
 193                         end
 194                         local node = find_after_innermost(parser.tree, range, startof, function(t, n, max_n)
 195                                 return not t.d or t.is_empty and n == max_n end)
 196                         return node and node.start, node
 197                 end,
 198
 199                 finish_float_before = function(range, up_empty_list)
 200                         if up_empty_list then
 201                                 local _, parent = sexp_at(range)
 202                                 if parent.is_empty then
 203                                         return parent.start, parent
 204                                 end
 205                         end
 206                         local node = find_before_innermost(parser.tree, range, finishof, function(t, n, _)
 207                                 return not t.d or t.is_empty and n == 1 end)
 208                         return node and node.finish + 1, node
 209                 end,
 210
 211                 finish_float_after = function(range, up_empty_list)
 212                         if up_empty_list then
 213                                 local _, parent = sexp_at(range)
 214                                 if parent.is_empty then
 215                                         return parent.finish + 1, parent
 216                                 end
 217                         end
 218                         local node = find_after_innermost(parser.tree, range, finishof, function(t, n, max_n)
 219                                 return not t.d or t.is_empty and n == max_n end)
 220                         return node and node.finish + 1, node
 221                 end,
 222
 223                 escaped_at = function(range)
 224                         local node = parser.escaped.around(range)
 225                         -- TODO: distinguish between doublequoted strings, chars, line comments, and block comments
 226                         -- and use approprite offset comparisons for each
 227                         return node and range.start > node.start and range.finish <= node.finish and node
 228                 end,
 229
 230                 prev_start_wrapped = function(range)
 231                         local node, parent = parser.tree.sexp_at(range)
 232                         if in_quasilist(node, range) then parent = node end
 233                         local pstart = parent.start and (parent.start + (parent.p and #parent.p or 0) + #parent.d)
 234                         local bol = bol_at(range.start)
 235                         local prev_wrapped = (parent.is_list or parent.is_root) and parent.find_before(range,
 236                                 function(t) return t.start < bol and t.finish > bol end,
 237                                 function(t) return t.finish < bol
 238                         end)
 239                         local prev_start = prev_wrapped and prev_wrapped.start or bol
 240                         pstart = pstart or prev_start
 241                         return math.max(pstart, prev_start)
 242                 end,
 243
 244                 next_finish_wrapped = function(range)
 245                         local node, parent = parser.tree.sexp_at(range)
 246                         if in_quasilist(node, range) then parent = node end
 247                         local pfinish = parent.finish and parent.finish + 1 - #parser.opposite[parent.d]
 248                         local eol = eol_at(range.start)
 249                         local next_wrapped = (parent.is_list or parent.is_root) and parent.find_after(range,
 250                                 function(t) return t.start < eol and t.finish > eol end,
 251                                 function(t) return t.start > eol
 252                         end)
 253                         local next_finish = next_wrapped and next_wrapped.finish + 1 or eol
 254                         -- XXX: second return value, to be used for safe line-commenting:
 255                         local next_start_on_line = math.min(pfinish or range.start, next_wrapped and next_wrapped.start or eol)
 256                         return math.min(pfinish or next_finish, next_finish), next_start_on_line < eol and next_start_on_line or nil
 257                 end,
 258
 259                 paragraph_start_before = function(range, prev_line)
 260                         local prev, n = parser.tree.before(range.start, startof, is_comment)
 261                         if not prev_line then
 262                                 return prev and prev.start
 263                         end
 264                         local pprev = n and parser.tree[n - 1]
 265                         local has_eol = pprev and pprev.is_comment and parser.opposite[pprev.d] == "\n"
 266                         local adjacent = pprev and prev and prev.start - (pprev.finish + (has_eol and 0 or 1)) <= 1
 267                         return prev and prev.start - ((adjacent or prev.start == 0) and 0 or 1)
 268                 end,
 269
 270                 paragraph_finish_after = function(range, next_line)
 271                         local node = parser.tree.around(range)
 272                         local nxt, n = parser.tree.find_after(node or range, function(t)
 273                                 return not t.is_comment and t.finish > range.finish
 274                         end)
 275                         return nxt and nxt.finish + 1 + (next_line and parser.tree[n + 1] and parser.tree[n + 1].indent and 1 or 0)
 276                 end,
 277
 278                 beginning_of_quasilist = function(range)
 279                         local _, parent = sexp_at(range)
 280                         return parent.start and (parent.start + (parent.p and #parent.p or 0) + #parent.d)
 281                 end,
 282
 283                 end_of_quasilist = function(range)
 284                         local _, parent = sexp_at(range)
 285                         return parent.finish and parent.finish + 1 - #parser.opposite[parent.d]
 286                 end,
 287
 288                 repl_line_begin = function(range)
 289                         local _, parent = parser.tree.sexp_at(range)
 290                         if not parent.is_root then return end
 291                         local prev_indent = parent.find_before(range, function(t) return t.indent end)
 292                         return prev_indent and prev_indent.start
 293                 end,
 294
 295                 wider_than = function(range)
 296                         local node, parent = parser.tree.sexp_at(range)
 297                         if not node and parent.is_root then return end
 298                         local pstart, pfinish
 299                         if in_quasilist(node, range) then
 300                                 parent = node
 301                                 node = node.word_at(range)
 302                         end
 303                         if not parent.is_root then
 304                                 pstart, pfinish = parent.start + (parent.p and #parent.p or 0) + #parent.d,
 305                                         parent.finish + 1 - #parser.opposite[parent.d]
 306                         end
 307                         local same_as_inner = range.start == pstart and range.finish == pfinish
 308                         local same_as_node = node and range.start == node.start and range.finish - 1 == node.finish
 309                         if node and not same_as_node then
 310                                 return node.start, node.finish + 1
 311                         elseif not same_as_inner then
 312                                 return pstart, pfinish
 313                         end
 314                         return parent.start, parent.finish + 1
 315                 end,
 316
 317                 sexp_at = sexp_at,
 318                 paragraph_at = parser.tree.around,
 319                 goto_path = parser.tree.goto_path,
 320                 sexp_path = parser.tree.sexp_path,
 321                 find_after = parser.tree.find_after,
 322                 find_before = parser.tree.find_before,
 323         }
 324 end
 325
 326 return M