vis

a vi-like editor based on Plan 9's structural regular expressions
textobject-lexer.lua

(735B)
      1 -- text object matching a lexer token
      2 
      3 local MAX_CONTEXT = 32768
      4 
      5 vis:textobject_new("ii", function(win, pos)
      6 
      7 	if not win.syntax or not vis.lexers.load then
      8 		return nil
      9 	end
     10 
     11 	local lexer = vis.lexers.load(win.syntax, nil, true)
     12 	if not lexer then
     13 		return nil
     14 	end
     15 
     16 	local before, after = pos - MAX_CONTEXT, pos + MAX_CONTEXT
     17 	if before < 0 then
     18 		before = 0
     19 	end
     20 	-- TODO make sure we start at a line boundary?
     21 
     22 	local data = win.file:content(before, after - before)
     23 	local tokens = lexer:lex(data)
     24 	local cur = before
     25 
     26 	for i = 1, #tokens, 2 do
     27 		local token_next = before + tokens[i+1] - 1
     28 		if cur <= pos and pos < token_next then
     29 			return cur, token_next
     30 		end
     31 		cur = token_next
     32 	end
     33 
     34 	return nil
     35 end, "Current lexer token")