Francesco Abbate
218999dff8
Detect when we are past the end of the string to avoid by checking if byte is not nil. Fix #510.
71 lines
2.3 KiB
Lua
71 lines
2.3 KiB
Lua
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-- So that in addition to regex.gsub(pattern, string), we can also do
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-- pattern:gsub(string).
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regex.__index = function(table, key) return regex[key]; end
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regex.match = function(pattern_string, string, offset, options)
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local pattern = type(pattern_string) == "table" and
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pattern_string or regex.compile(pattern_string)
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return regex.cmatch(pattern, string, offset or 1, options or 0)
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end
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-- Will iterate back through any UTF-8 bytes so that we don't replace bits
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-- mid character.
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local function previous_character(str, index)
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local byte
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repeat
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index = index - 1
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byte = string.byte(str, index)
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until byte < 128 or byte >= 192
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return index
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end
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-- Moves to the end of the identified character.
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local function end_character(str, index)
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local byte = string.byte(str, index + 1)
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while byte and byte >= 128 and byte < 192 do
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index = index + 1
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byte = string.byte(str, index + 1)
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end
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return index
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end
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-- Build off matching. For now, only support basic replacements, but capture
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-- groupings should be doable. We can even have custom group replacements and
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-- transformations and stuff in lua. Currently, this takes group replacements
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-- as \1 - \9.
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-- Should work on UTF-8 text.
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regex.gsub = function(pattern_string, str, replacement)
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local pattern = type(pattern_string) == "table" and
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pattern_string or regex.compile(pattern_string)
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local result, indices = ""
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local matches, replacements = {}, {}
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repeat
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indices = { regex.cmatch(pattern, str) }
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if #indices > 0 then
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table.insert(matches, indices)
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local currentReplacement = replacement
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if #indices > 2 then
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for i = 1, (#indices/2 - 1) do
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currentReplacement = string.gsub(
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currentReplacement,
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"\\" .. i,
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str:sub(indices[i*2+1], end_character(str,indices[i*2+2]-1))
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)
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end
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end
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currentReplacement = string.gsub(currentReplacement, "\\%d", "")
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table.insert(replacements, { indices[1], #currentReplacement+indices[1] })
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if indices[1] > 1 then
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result = result ..
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str:sub(1, previous_character(str, indices[1])) .. currentReplacement
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else
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result = result .. currentReplacement
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end
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str = str:sub(indices[2])
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end
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until #indices == 0 or indices[1] == indices[2]
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return result .. str, matches, replacements
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end
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