mirror of
https://github.com/linux-man/LoveFrames.git
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113 lines
4.0 KiB
Lua
113 lines
4.0 KiB
Lua
return function(utf8)
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local cl = utf8:require "charclass.compiletime.builder"
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local next = utf8.util.next
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local token = 1
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local function parse(str, c, bs, ctx)
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local tttt = token
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token = token + 1
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local class
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local nbs = bs
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utf8.debug("cc_parse", tttt, str, c, nbs, next(str, nbs))
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if c == '%' then
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c, nbs = next(str, bs)
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local _c = utf8.raw.lower(c)
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local matched
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if _c == 'a' then
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matched = ('alpha')
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elseif _c == 'c' then
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matched = ('cntrl')
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elseif _c == 'd' then
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matched = ('digit')
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elseif _c == 'g' then
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matched = ('graph')
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elseif _c == 'l' then
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matched = ('lower')
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elseif _c == 'p' then
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matched = ('punct')
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elseif _c == 's' then
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matched = ('space')
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elseif _c == 'u' then
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matched = ('upper')
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elseif _c == 'w' then
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matched = ('alnum')
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elseif _c == 'x' then
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matched = ('xdigit')
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end
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if matched then
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if _c ~= c then
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class = cl.new():without_classes(matched)
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else
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class = cl.new():with_classes(matched)
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end
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end
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elseif c == '[' then
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local old_internal = ctx.internal
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ctx.internal = true
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class = cl.new()
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local firstletter = true
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while true do
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local prev_nbs = nbs
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c, nbs = next(str, nbs)
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utf8.debug("next", tttt, c, nbs)
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if c == '^' and firstletter then
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class:invert()
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elseif c == ']' then
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utf8.debug('] on pos', tttt, nbs)
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break
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elseif c == '' then
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error "malformed pattern (missing ']')"
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else
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local sub_class, skip = utf8.regex.compiletime.charclass.parse(str, c, nbs, ctx)
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nbs = prev_nbs + skip
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utf8.debug("include", tttt, bs, prev_nbs, nbs, skip)
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class:include(sub_class)
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end
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firstletter = false
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end
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ctx.internal = old_internal
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elseif c == '.' then
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if not ctx.internal then
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class = cl.new():invert()
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else
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class = cl.new():with_codes(c)
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end
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end
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return class, utf8.next(str, nbs) - bs
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end
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return parse
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end
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--[[
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x: (where x is not one of the magic characters ^$()%.[]*+-?) represents the character x itself.
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.: (a dot) represents all characters.
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%a: represents all letters.
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%c: represents all control characters.
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%d: represents all digits.
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%g: represents all printable characters except space.
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%l: represents all lowercase letters.
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%p: represents all punctuation characters.
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%s: represents all space characters.
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%u: represents all uppercase letters.
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%w: represents all alphanumeric characters.
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%x: represents all hexadecimal digits.
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%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.
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[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.
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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.)
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The interaction between ranges and classes is not defined. Therefore, patterns like [%a-z] or [a-%%] have no meaning.
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[^set]: represents the complement of set, where set is interpreted as above.
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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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]]
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