lite-xl/data/core/regex.lua

70 lines
2.2 KiB
Lua

-- So that in addition to regex.gsub(pattern, string), we can also do
-- pattern:gsub(string).
regex.__index = function(table, key) return regex[key]; end
regex.match = function(pattern_string, string, offset, options)
local pattern = type(pattern_string) == "table" and
pattern_string or regex.compile(pattern_string)
return regex.cmatch(pattern, string, offset, options)
end
-- Will iterate back through any UTF-8 bytes so that we don't replace bits
-- mid character.
local function previous_character(str, index)
local byte
repeat
index = index - 1
byte = string.byte(str, index)
until byte < 128 or byte >= 192
return index
end
-- Moves to the end of the identified character.
local function end_character(str, index)
local byte = string.byte(str, index + 1)
while byte >= 128 and byte < 192 do
index = index + 1
byte = string.byte(str, index + 1)
end
return index
end
-- Build off matching. For now, only support basic replacements, but capture
-- groupings should be doable. We can even have custom group replacements and
-- transformations and stuff in lua. Currently, this takes group replacements
-- as \1 - \9.
-- Should work on UTF-8 text.
regex.gsub = function(pattern_string, str, replacement)
local pattern = type(pattern_string) == "table" and
pattern_string or regex.compile(pattern_string)
local result, indices = ""
local n = 0
repeat
indices = { regex.cmatch(pattern, str) }
if #indices > 0 then
n = n + 1
local currentReplacement = replacement
if #indices > 2 then
for i = 1, (#indices/2 - 1) do
currentReplacement = string.gsub(
currentReplacement,
"\\" .. i,
str:sub(indices[i*2+1], end_character(str,indices[i*2+2]-1))
)
end
end
currentReplacement = string.gsub(currentReplacement, "\\%d", "")
if indices[1] > 1 then
result = result ..
str:sub(1, previous_character(str, indices[1])) .. currentReplacement
else
result = result .. currentReplacement
end
str = str:sub(indices[2])
end
until #indices == 0 or indices[1] == indices[2]
return result .. str, n
end