Aegisub/aegisub/automation/include/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.
-- Get the boost::regex binding
regex = aegisub.__init_regex()
-- Return the first n elements from ...
select_first = (n, a, ...) ->
if n == 0 then return
a, select_first n - 1, ...
-- Extract the flags from ..., bitwise OR them together, and move them to the
-- front of ...
unpack_args = (...) ->
userdata_start = nil
for i = 1, select '#', ...
v = select i, ...
if type(v) == 'userdata'
userdata_start = i
break
return 0, ... unless userdata_start
flags = regex.process_flags select userdata_start, ...
if type(flags) == 'string'
error(flags, 3)
flags, select_first userdata_start - 1, ...
-- Typecheck a variable and throw an error if it fails
check_arg = (arg, expected_type, argn, func_name, level) ->
if type(arg) != expected_type
error "Argument #{argn} to #{func_name} should be a '#{expected_type}', is '#{type(arg)}' (#{arg})",
level + 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) =>
start = 1
gsplit: (str, skip_empty, max_split) =>
@_check_self!
check_arg str, 'string', 2, 'gsplit', @_level
if not max_split or max_split <= 0 then max_split = str\len()
start = 1
prev = 1
do_split = () ->
if not str or str\len() == 0 then return
local first, last
if max_split > 0
first, last = regex.search @_regex, str, start
if not first or first > str\len()
ret = str\sub prev, str\len()
str = nil
return ret
ret = str\sub prev, first - 1
prev = last + 1
start = 1 + if start >= last then start else last
if skip_empty and ret\len() == 0
do_split()
else
max_split -= 1
ret
do_split
split: (str, skip_empty, max_split) =>
@_check_self!
check_arg str, 'string', 2, 'split', @_level
[v for v in @gsplit str, skip_empty, max_split]
gfind: (str) =>
@_check_self!
check_arg str, 'string', 2, 'gfind', @_level
start = 1
->
first, last = regex.search(@_regex, str, start)
return unless first
start = if last >= start then last + 1 else start + 1
str\sub(first, last), first, last
find: (str) =>
@_check_self!
check_arg str, 'string', 2, 'find', @_level
ret = [str: s, first: f, last: l for s, f, l in @gfind(str)]
next(ret) and ret
sub: (str, repl, max_count) =>
@_check_self!
check_arg str, 'string', 2, 'sub', @_level
if max_count != nil
check_arg max_count, 'number', 4, 'sub', @_level
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'
regex.replace @_regex, repl, str, max_count
else
error "Argument 2 to sub should be a string or function, is '#{type(repl)}' (#{repl})", @_level
gmatch: (str, start) =>
@_check_self!
check_arg str, 'string', 2, 'gmatch', @_level
start = if start then start - 1 else 0
match = regex.match @_regex, str, start
i = 1
->
return unless match
first, last = regex.get_match match, i
return unless first
i += 1
{
str: str\sub first + start, last + start
first: first + start
last: last + start
}
match: (str, start) =>
@_check_self!
check_arg(str, 'string', 2, 'match', @_level)
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 = regex.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) ->
(str, pattern, ...) ->
check_arg str, 'string', 1, impl_name, 2
check_arg pattern, 'string', 2, impl_name, 2
invoke str, pattern, impl_name, unpack_args ...
-- And now at last the actual public API
re = regex.init_flags(re)
re.compile = (pattern, ...) ->
check_arg pattern, 'string', 1, 'compile', 2
real_compile pattern, 2, regex.process_flags(...), 2
re.split = gen_wrapper 'split'
re.gsplit = gen_wrapper 'gsplit'
re.find = gen_wrapper 'find'
re.gfind = gen_wrapper 'gfind'
re.match = gen_wrapper 'match'
re.gmatch = gen_wrapper 'gmatch'
re.sub = gen_wrapper 'sub'
re