120 lines
3.5 KiB
Lua
120 lines
3.5 KiB
Lua
--[[
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List.lua
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Copyright © 2017 Albert Krewinkel
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Permission to use, copy, modify, and/or distribute this software for any purpose
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with or without fee is hereby granted, provided that the above copyright notice
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and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
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INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
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OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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THIS SOFTWARE.
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]]
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--- Pandoc's List type and helper methods
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-- @classmod pandoc.List
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-- @author Albert Krewinkel
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-- @copyright © 2017 Albert Krewinkel
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-- @license MIT
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local List = {
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_VERSION = "0.1.0"
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}
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function List:new (o)
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o = o or {}
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setmetatable(o, self)
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self.__index = self
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return o
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end
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function List:__call (o)
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return self:new(o)
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end
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--- Concatenates two lists.
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-- @param list second list concatenated to the first
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-- @return a new list containing all elements from list1 and list2
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function List:__concat (list)
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local res = List.clone(self)
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List.extend(res, list)
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return res
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end
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--- Returns a (shallow) copy of the list.
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function List:clone ()
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local lst = setmetatable({}, getmetatable(self))
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List.extend(lst, self)
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return lst
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end
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--- Checks if the list has an item equal to the given needle.
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-- @param needle item to search for
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-- @param init index at which the search is started
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-- @return true if a list item is equal to the needle, false otherwise
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function List:includes (needle, init)
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return not (List.find(self, needle, init) == nil)
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end
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--- Returns the value and index of the first occurrence of the given item.
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-- @param needle item to search for
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-- @param init index at which the search is started
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-- @return first item equal to the needle, or nil if no such item exists.
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-- @return index of that element
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function List:find (needle, init)
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return List.find_if(self, function(x) return x == needle end, init)
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end
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--- Returns the value and index of the first element for which the predicate
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--- holds true.
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-- @param pred the predicate function
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-- @param init index at which the search is started
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-- @return first item for which `test` succeeds, or nil if no such item exists.
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-- @return index of that element
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function List:find_if (pred, init)
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init = (init == nil and 1) or (init < 0 and #self - init) or init
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for i = init, #self do
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if pred(self[i], i) then
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return self[i], i
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end
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end
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return nil
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end
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--- Adds the given list to the end of this list.
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-- @param list list to appended
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function List:extend (list)
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for i = 1, #list do
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self[#self + 1] = list[i]
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end
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end
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--- Returns a copy of the current list by applying the given function to all
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-- elements.
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-- @param fn function which is applied to all list items.
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function List:map (fn)
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local res = setmetatable({}, getmetatable(self))
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for i = 1, #self do
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res[i] = fn(self[i], i)
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end
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return res
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end
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--- Returns a new list containing all items satisfying a given condition.
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-- @param pred condition items must satisfy.
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-- @return a new list containing all items for which `test` was true.
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function List:filter (pred)
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local res = setmetatable({}, getmetatable(self))
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for i = 1, #self do
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if pred(self[i], i) then
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res[#res + 1] = self[i]
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end
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end
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return res
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end
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return List
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