Aegisub/automation/include/aegisub/re.moon

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-- Copyright (c) 2012, Thomas Goyne <plorkyeran@aegisub.org>
--
-- Permission to use, copy, modify, and distribute this software for any
-- purpose with or without fee is hereby granted, provided that the above
-- copyright notice and this permission notice appear in all copies.
--
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
-- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
error = error
next = next
select = select
type = type
bit = require 'bit'
ffi = require 'ffi'
ffi_util = require 'aegisub.ffi'
check = require 'aegisub.argcheck'
ffi.cdef[[
typedef struct agi_re_flag {
const char *name;
int value;
} agi_re_flag;
]]
regex_flag = ffi.typeof 'agi_re_flag'
-- Get the boost::eegex binding
regex = require 'aegisub.__re_impl'
-- Wrappers to convert returned values from C types to Lua types
search = (re, str, start) ->
return unless start <= str\len()
res = regex.search re, str, str\len(), start
return unless res != nil
first, last = res[0], res[1]
ffi.gc(res, ffi.C.free)
first, last
replace = (re, replacement, str, max_count) ->
ffi_util.string regex.replace re, replacement, str, str\len(), max_count
match = (re, str, start) ->
assert start <= str\len()
m = regex.match re, str, str\len(), start
return unless m != nil
ffi.gc m, regex.match_free
get_match = (m, idx) ->
res = regex.get_match m, idx
return unless res != nil
res[0], res[1] -- Result buffer is owned by match so no need to free
err_buff = ffi.new 'char *[1]'
compile = (pattern, flags) ->
err_buff[0] = nil
re = regex.compile pattern, flags, err_buff
if err_buff[0] != nil
return ffi.string err_buff[0]
ffi.gc re, regex.regex_free
-- Return the first n elements from ...
select_first = (n, a, ...) ->
if n == 0 then return
a, select_first n - 1, ...
-- Bitwise-or together regex flags passed as arguments to a function
process_flags = (...) ->
flags = 0
for i = 1, select '#', ...
v = select i, ...
if not ffi.istype regex_flag, v
error 'Flags must follow all non-flag arguments', 3
flags = bit.bor flags, v.value
flags
-- Extract the flags from ..., bitwise OR them together, and move them to the
-- front of ...
unpack_args = (...) ->
flags_start = nil
for i = 1, select '#', ...
v = select i, ...
if ffi.istype regex_flag, v
flags_start = i
break
return 0, ... unless flags_start
process_flags(select flags_start, ...), select_first flags_start - 1, ...
-- Replace a match with the value returned from func when passed the match
replace_match = (match, func, str, last, acc) ->
-- Copy everything between the last match and this match
if last < match.last
acc[#acc + 1] = str\sub last, match.first - 1
repl = func match.str, match.first, match.last
-- If it didn't return a string just leave the old value
acc[#acc + 1] = if type(repl) == 'string' then repl else match.str
match.first, match.last + 1
-- Replace all matches from a single iteration of the regexp
do_single_replace_fun = (re, func, str, acc, pos) ->
matches = re\match str, pos
-- No more matches so just return what's left of the input
return pos unless matches
-- If there's only one match then there's no capturing groups and we need
-- to pass the entire match to the replace function, but if there's
-- multiple then we want to skip the full match and only pass the capturing
-- groups.
start = if #matches == 1 then 1 else 2
last = pos
local first
for i = start, #matches
first, last = replace_match matches[i], func, str, last, acc
-- Always eat at least one character from the input or we'll just make the
-- same match max_count times
if first == last
acc[#acc + 1] = str\sub last, last
last += 1
return last, matches[1].first <= str\len()
do_replace_fun = (re, func, str, max) ->
acc = {}
pos = 1
local i
for i = 1, max do
pos, more = do_single_replace_fun re, func, str, acc, pos
unless more
max = i
break
table.concat(acc, '') .. str\sub pos
-- Compiled regular expression type protoype
class RegEx
-- Verify that a valid value was passed for self
_check_self: =>
unless @__class == RegEx
error 're method called with invalid self. You probably used . when : is needed.', 3
new: (@_regex, @_level) =>
gsplit: check'RegEx string ?boolean ?number' (str, skip_empty, max_split) =>
if not max_split or max_split <= 0 then max_split = str\len()
start = 0
prev = 1
do_split = () ->
if not str or str\len() == 0 then return
local first, last
if max_split > 0
first, last = search @_regex, str, start
if not first or first > str\len()
ret = str\sub prev, str\len()
str = nil
return if skip_empty and ret\len() == 0 then nil else ret
ret = str\sub prev, first - 1
prev = last + 1
start = if start >= last then start + 1 else last
if skip_empty and ret\len() == 0
do_split()
else
max_split -= 1
ret
do_split
split: check'RegEx string ?boolean ?number' (str, skip_empty, max_split) =>
[v for v in @gsplit str, skip_empty, max_split]
gfind: check'RegEx string' (str) =>
start = 0
->
first, last = search(@_regex, str, start)
return unless first
start = if last > start then last else start + 1
str\sub(first, last), first, last
find: check'RegEx string' (str) =>
ret = [str: s, first: f, last: l for s, f, l in @gfind(str)]
next(ret) and ret
sub: check'RegEx string string|function ?number' (str, repl, max_count) =>
max_count = str\len() + 1 if not max_count or max_count == 0
if type(repl) == 'function'
do_replace_fun @, repl, str, max_count
elseif type(repl) == 'string'
replace @_regex, repl, str, max_count
gmatch: check'RegEx string ?number' (str, start) =>
start = if start then start - 1 else 0
m = match @_regex, str, start
i = 0
->
return unless m
first, last = get_match m, i
return unless first
i += 1
{
str: str\sub first + start, last + start
first: first + start
last: last + start
}
match: check'RegEx string ?number' (str, start) =>
ret = [v for v in @gmatch str, start]
-- Return nil rather than a empty table so that if re.match(...) works
return nil if next(ret) == nil
ret
-- Create a regex object from a pattern, flags, and error depth
real_compile = (pattern, level, flags, stored_level) ->
if pattern == ''
error 'Regular expression must not be empty', level + 1
re = compile pattern, flags
if type(re) == 'string'
error regex, level + 1
RegEx re, stored_level or level + 1
-- Compile a pattern then invoke a method on it
invoke = (str, pattern, fn, flags, ...) ->
compiled_regex = real_compile(pattern, 3, flags)
compiled_regex[fn](compiled_regex, str, ...)
-- Generate a static version of a method with arg type checking
gen_wrapper = (impl_name) -> check'string string ...' (str, pattern, ...) ->
invoke str, pattern, impl_name, unpack_args ...
-- And now at last the actual public API
do
re = {
compile: check'string ...' (pattern, ...) ->
real_compile pattern, 2, process_flags(...), 2
split: gen_wrapper 'split'
gsplit: gen_wrapper 'gsplit'
find: gen_wrapper 'find'
gfind: gen_wrapper 'gfind'
match: gen_wrapper 'match'
gmatch: gen_wrapper 'gmatch'
sub: gen_wrapper 'sub'
}
i = 0
flags = regex.get_flags()
while flags[i].name != nil
re[ffi.string flags[i].name] = flags[i]
i += 1
re