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return function(utf8)
local cl = utf8:require "charclass.compiletime.builder"
local next = utf8.util.next
local token = 1
local function parse(str, c, bs, ctx)
local tttt = token
token = token + 1
local class
local nbs = bs
utf8.debug("cc_parse", tttt, str, c, nbs, next(str, nbs))
if c == '%' then
c, nbs = next(str, bs)
if c == '' then
error("malformed pattern (ends with '%')")
end
local _c = utf8.raw.lower(c)
local matched
if _c == 'a' then
matched = ('alpha')
elseif _c == 'c' then
matched = ('cntrl')
elseif _c == 'd' then
matched = ('digit')
elseif _c == 'g' then
matched = ('graph')
elseif _c == 'l' then
matched = ('lower')
elseif _c == 'p' then
matched = ('punct')
elseif _c == 's' then
matched = ('space')
elseif _c == 'u' then
matched = ('upper')
elseif _c == 'w' then
matched = ('alnum')
elseif _c == 'x' then
matched = ('xdigit')
end
if matched then
if _c ~= c then
class = cl.new():without_classes(matched)
else
class = cl.new():with_classes(matched)
end
elseif _c == 'z' then
class = cl.new():with_codes(0)
if _c ~= c then
class = class:invert()
end
else
class = cl.new():with_codes(c)
end
elseif c == '[' and not ctx.internal then
local old_internal = ctx.internal
ctx.internal = true
class = cl.new()
local firstletter = true
while true do
local prev_nbs = nbs
c, nbs = next(str, nbs)
utf8.debug("next", tttt, c, nbs)
if c == '^' and firstletter then
class:invert()
local nc, nnbs = next(str, nbs)
if nc == ']' then
class:with_codes(nc)
nbs = nnbs
end
elseif c == ']' then
if firstletter then
class:with_codes(c)
else
utf8.debug('] on pos', tttt, nbs)
break
end
elseif c == '' then
error "malformed pattern (missing ']')"
else
local sub_class, skip = utf8.regex.compiletime.charclass.parse(str, c, nbs, ctx)
nbs = prev_nbs + skip
utf8.debug("include", tttt, bs, prev_nbs, nbs, skip)
class:include(sub_class)
end
firstletter = false
end
ctx.internal = old_internal
elseif c == '.' then
if not ctx.internal then
class = cl.new():invert()
else
class = cl.new():with_codes(c)
end
end
return class, utf8.next(str, nbs) - bs
end
return parse
end
--[[
x: (where x is not one of the magic characters ^$()%.[]*+-?) represents the character x itself.
.: (a dot) represents all characters.
%a: represents all letters.
%c: represents all control characters.
%d: represents all digits.
%g: represents all printable characters except space.
%l: represents all lowercase letters.
%p: represents all punctuation characters.
%s: represents all space characters.
%u: represents all uppercase letters.
%w: represents all alphanumeric characters.
%x: represents all hexadecimal digits.
%x: (where x is any non-alphanumeric character) represents the character x. This is the standard way to escape the magic characters. Any non-alphanumeric character (including all punctuation characters, even the non-magical) can be preceded by a '%' when used to represent itself in a pattern.
[set]: represents the class which is the union of all characters in set. A range of characters can be specified by separating the end characters of the range, in ascending order, with a '-'. All classes %x described above can also be used as components in set. All other characters in set represent themselves. For example, [%w_] (or [_%w]) represents all alphanumeric characters plus the underscore, [0-7] represents the octal digits, and [0-7%l%-] represents the octal digits plus the lowercase letters plus the '-' character.
You can put a closing square bracket in a set by positioning it as the first character in the set. You can put a hyphen in a set by positioning it as the first or the last character in the set. (You can also use an escape for both cases.)
The interaction between ranges and classes is not defined. Therefore, patterns like [%a-z] or [a-%%] have no meaning.
[^set]: represents the complement of set, where set is interpreted as above.
For all classes represented by single letters (%a, %c, etc.), the corresponding uppercase letter represents the complement of the class. For instance, %S represents all non-space characters.
]]
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