mirror of https://github.com/neovim/neovim.git
1068 lines
25 KiB
Lua
1068 lines
25 KiB
Lua
---@defgroup vim.iter
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---
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--- \*vim.iter()\* is an interface for |iterable|s: it wraps a table or function argument into an
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--- \*Iter\* object with methods (such as |Iter:filter()| and |Iter:map()|) that transform the
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--- underlying source data. These methods can be chained to create iterator "pipelines": the output
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--- of each pipeline stage is input to the next stage. The first stage depends on the type passed to
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--- `vim.iter()`:
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---
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--- - List tables (arrays, |lua-list|) yield only the value of each element.
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--- - Use |Iter:enumerate()| to also pass the index to the next stage.
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--- - Or initialize with ipairs(): `vim.iter(ipairs(…))`.
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--- - Non-list tables (|lua-dict|) yield both the key and value of each element.
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--- - Function |iterator|s yield all values returned by the underlying function.
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--- - Tables with a |__call()| metamethod are treated as function iterators.
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---
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--- The iterator pipeline terminates when the underlying |iterable| is exhausted (for function
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--- iterators this means it returned nil).
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---
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--- Note: `vim.iter()` scans table input to decide if it is a list or a dict; to avoid this cost you
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--- can wrap the table with an iterator e.g. `vim.iter(ipairs({…}))`, but that precludes the use of
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--- |list-iterator| operations such as |Iter:rev()|).
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---
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--- Examples:
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---
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--- ```lua
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--- local it = vim.iter({ 1, 2, 3, 4, 5 })
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--- it:map(function(v)
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--- return v * 3
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--- end)
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--- it:rev()
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--- it:skip(2)
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--- it:totable()
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--- -- { 9, 6, 3 }
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---
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--- -- ipairs() is a function iterator which returns both the index (i) and the value (v)
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--- vim.iter(ipairs({ 1, 2, 3, 4, 5 })):map(function(i, v)
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--- if i > 2 then return v end
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--- end):totable()
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--- -- { 3, 4, 5 }
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---
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--- local it = vim.iter(vim.gsplit('1,2,3,4,5', ','))
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--- it:map(function(s) return tonumber(s) end)
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--- for i, d in it:enumerate() do
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--- print(string.format("Column %d is %d", i, d))
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--- end
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--- -- Column 1 is 1
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--- -- Column 2 is 2
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--- -- Column 3 is 3
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--- -- Column 4 is 4
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--- -- Column 5 is 5
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---
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--- vim.iter({ a = 1, b = 2, c = 3, z = 26 }):any(function(k, v)
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--- return k == 'z'
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--- end)
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--- -- true
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---
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--- local rb = vim.ringbuf(3)
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--- rb:push("a")
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--- rb:push("b")
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--- vim.iter(rb):totable()
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--- -- { "a", "b" }
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--- ```
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---
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--- In addition to the |vim.iter()| function, the |vim.iter| module provides
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--- convenience functions like |vim.iter.filter()| and |vim.iter.totable()|.
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---@class IterMod
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---@operator call:Iter
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local M = {}
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---@class Iter
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local Iter = {}
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Iter.__index = Iter
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Iter.__call = function(self)
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return self:next()
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end
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--- Special case implementations for iterators on list tables.
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---@class ListIter : Iter
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---@field _table table Underlying table data
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---@field _head number Index to the front of a table iterator
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---@field _tail number Index to the end of a table iterator (exclusive)
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local ListIter = {}
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ListIter.__index = setmetatable(ListIter, Iter)
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ListIter.__call = function(self)
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return self:next()
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end
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--- Packed tables use this as their metatable
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local packedmt = {}
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local function unpack(t)
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if type(t) == 'table' and getmetatable(t) == packedmt then
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return _G.unpack(t, 1, t.n)
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end
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return t
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end
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local function pack(...)
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local n = select('#', ...)
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if n > 1 then
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return setmetatable({ n = n, ... }, packedmt)
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end
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return ...
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end
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local function sanitize(t)
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if type(t) == 'table' and getmetatable(t) == packedmt then
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-- Remove length tag
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t.n = nil
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end
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return t
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end
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--- Determine if the current iterator stage should continue.
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---
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--- If any arguments are passed to this function, then return those arguments
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--- and stop the current iterator stage. Otherwise, return true to signal that
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--- the current stage should continue.
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---
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---@param ... any Function arguments.
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---@return boolean True if the iterator stage should continue, false otherwise
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---@return any Function arguments.
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local function continue(...)
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if select(1, ...) ~= nil then
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return false, ...
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end
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return true
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end
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--- If no input arguments are given return false, indicating the current
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--- iterator stage should stop. Otherwise, apply the arguments to the function
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--- f. If that function returns no values, the current iterator stage continues.
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--- Otherwise, those values are returned.
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---
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---@param f function Function to call with the given arguments
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---@param ... any Arguments to apply to f
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---@return boolean True if the iterator pipeline should continue, false otherwise
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---@return any Return values of f
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local function apply(f, ...)
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if select(1, ...) ~= nil then
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return continue(f(...))
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end
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return false
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end
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--- Filters an iterator pipeline.
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---
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--- Example:
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---
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--- ```lua
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--- local bufs = vim.iter(vim.api.nvim_list_bufs()):filter(vim.api.nvim_buf_is_loaded)
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--- ```
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---
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---@param f function(...):bool Takes all values returned from the previous stage
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--- in the pipeline and returns false or nil if the
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--- current iterator element should be removed.
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---@return Iter
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function Iter.filter(self, f)
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return self:map(function(...)
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if f(...) then
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return ...
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end
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end)
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end
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---@private
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function ListIter.filter(self, f)
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local inc = self._head < self._tail and 1 or -1
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local n = self._head
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for i = self._head, self._tail - inc, inc do
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local v = self._table[i]
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if f(unpack(v)) then
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self._table[n] = v
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n = n + inc
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end
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end
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self._tail = n
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return self
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end
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--- Maps the items of an iterator pipeline to the values returned by `f`.
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---
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--- If the map function returns nil, the value is filtered from the iterator.
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---
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--- Example:
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---
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--- ```lua
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--- local it = vim.iter({ 1, 2, 3, 4 }):map(function(v)
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--- if v % 2 == 0 then
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--- return v * 3
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--- end
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--- end)
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--- it:totable()
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--- -- { 6, 12 }
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--- ```
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---
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---@param f function(...):any Mapping function. Takes all values returned from
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--- the previous stage in the pipeline as arguments
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--- and returns one or more new values, which are used
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--- in the next pipeline stage. Nil return values
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--- are filtered from the output.
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---@return Iter
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function Iter.map(self, f)
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-- Implementation note: the reader may be forgiven for observing that this
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-- function appears excessively convoluted. The problem to solve is that each
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-- stage of the iterator pipeline can return any number of values, and the
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-- number of values could even change per iteration. And the return values
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-- must be checked to determine if the pipeline has ended, so we cannot
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-- naively forward them along to the next stage.
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--
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-- A simple approach is to pack all of the return values into a table, check
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-- for nil, then unpack the table for the next stage. However, packing and
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-- unpacking tables is quite slow. There is no other way in Lua to handle an
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-- unknown number of function return values than to simply forward those
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-- values along to another function. Hence the intricate function passing you
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-- see here.
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local next = self.next
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--- Drain values from the upstream iterator source until a value can be
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--- returned.
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---
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--- This is a recursive function. The base case is when the first argument is
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--- false, which indicates that the rest of the arguments should be returned
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--- as the values for the current iteration stage.
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---
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---@param cont boolean If true, the current iterator stage should continue to
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--- pull values from its upstream pipeline stage.
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--- Otherwise, this stage is complete and returns the
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--- values passed.
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---@param ... any Values to return if cont is false.
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---@return any
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local function fn(cont, ...)
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if cont then
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return fn(apply(f, next(self)))
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end
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return ...
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end
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self.next = function()
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return fn(apply(f, next(self)))
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end
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return self
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end
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---@private
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function ListIter.map(self, f)
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local inc = self._head < self._tail and 1 or -1
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local n = self._head
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for i = self._head, self._tail - inc, inc do
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local v = pack(f(unpack(self._table[i])))
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if v ~= nil then
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self._table[n] = v
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n = n + inc
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end
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end
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self._tail = n
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return self
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end
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--- Calls a function once for each item in the pipeline, draining the iterator.
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---
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--- For functions with side effects. To modify the values in the iterator, use |Iter:map()|.
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---
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---@param f function(...) Function to execute for each item in the pipeline.
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--- Takes all of the values returned by the previous stage
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--- in the pipeline as arguments.
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function Iter.each(self, f)
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local function fn(...)
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if select(1, ...) ~= nil then
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f(...)
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return true
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end
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end
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while fn(self:next()) do
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end
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end
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---@private
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function ListIter.each(self, f)
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local inc = self._head < self._tail and 1 or -1
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for i = self._head, self._tail - inc, inc do
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f(unpack(self._table[i]))
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end
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self._head = self._tail
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end
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--- Collect the iterator into a table.
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---
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--- The resulting table depends on the initial source in the iterator pipeline.
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--- List-like tables and function iterators will be collected into a list-like
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--- table. If multiple values are returned from the final stage in the iterator
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--- pipeline, each value will be included in a table.
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---
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--- Examples:
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---
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--- ```lua
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--- vim.iter(string.gmatch('100 20 50', '%d+')):map(tonumber):totable()
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--- -- { 100, 20, 50 }
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---
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--- vim.iter({ 1, 2, 3 }):map(function(v) return v, 2 * v end):totable()
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--- -- { { 1, 2 }, { 2, 4 }, { 3, 6 } }
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---
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--- vim.iter({ a = 1, b = 2, c = 3 }):filter(function(k, v) return v % 2 ~= 0 end):totable()
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--- -- { { 'a', 1 }, { 'c', 3 } }
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--- ```
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---
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--- The generated table is a list-like table with consecutive, numeric indices.
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--- To create a map-like table with arbitrary keys, use |Iter:fold()|.
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---
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---
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---@return table
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function Iter.totable(self)
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local t = {}
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while true do
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local args = pack(self:next())
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if args == nil then
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break
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end
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t[#t + 1] = sanitize(args)
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end
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return t
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end
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---@private
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function ListIter.totable(self)
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if self.next ~= ListIter.next or self._head >= self._tail then
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return Iter.totable(self)
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end
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local needs_sanitize = getmetatable(self._table[1]) == packedmt
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-- Reindex and sanitize.
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local len = self._tail - self._head
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if needs_sanitize then
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for i = 1, len do
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self._table[i] = sanitize(self._table[self._head - 1 + i])
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end
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else
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for i = 1, len do
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self._table[i] = self._table[self._head - 1 + i]
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end
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end
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for i = len + 1, table.maxn(self._table) do
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self._table[i] = nil
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end
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self._head = 1
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self._tail = len + 1
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return self._table
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end
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--- Collect the iterator into a delimited string.
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---
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--- Each element in the iterator is joined into a string separated by {delim}.
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---
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--- Consumes the iterator.
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---
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--- @param delim string Delimiter
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--- @return string
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function Iter.join(self, delim)
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return table.concat(self:totable(), delim)
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end
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--- Folds ("reduces") an iterator into a single value.
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---
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--- Examples:
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---
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--- ```lua
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--- -- Create a new table with only even values
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--- local t = { a = 1, b = 2, c = 3, d = 4 }
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--- local it = vim.iter(t)
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--- it:filter(function(k, v) return v % 2 == 0 end)
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--- it:fold({}, function(t, k, v)
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--- t[k] = v
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--- return t
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--- end)
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--- -- { b = 2, d = 4 }
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--- ```
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---
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---@generic A
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---
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---@param init A Initial value of the accumulator.
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---@param f function(acc:A, ...):A Accumulation function.
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---@return A
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function Iter.fold(self, init, f)
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local acc = init
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--- Use a closure to handle var args returned from iterator
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local function fn(...)
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if select(1, ...) ~= nil then
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acc = f(acc, ...)
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return true
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end
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end
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while fn(self:next()) do
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end
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return acc
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end
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---@private
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function ListIter.fold(self, init, f)
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local acc = init
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local inc = self._head < self._tail and 1 or -1
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for i = self._head, self._tail - inc, inc do
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acc = f(acc, unpack(self._table[i]))
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end
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return acc
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end
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--- Gets the next value from the iterator.
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---
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--- Example:
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---
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--- ```lua
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---
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--- local it = vim.iter(string.gmatch('1 2 3', '%d+')):map(tonumber)
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--- it:next()
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--- -- 1
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--- it:next()
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--- -- 2
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--- it:next()
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--- -- 3
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---
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--- ```
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---
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---@return any
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---@diagnostic disable-next-line: unused-local
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function Iter.next(self) -- luacheck: no unused args
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-- This function is provided by the source iterator in Iter.new. This definition exists only for
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-- the docstring
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end
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---@private
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function ListIter.next(self)
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if self._head ~= self._tail then
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local v = self._table[self._head]
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local inc = self._head < self._tail and 1 or -1
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self._head = self._head + inc
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return unpack(v)
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end
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end
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--- Reverses a |list-iterator| pipeline.
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---
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--- Example:
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---
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--- ```lua
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---
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--- local it = vim.iter({ 3, 6, 9, 12 }):rev()
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--- it:totable()
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--- -- { 12, 9, 6, 3 }
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---
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--- ```
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---
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---@return Iter
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function Iter.rev(self)
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error('rev() requires a list-like table')
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return self
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end
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---@private
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function ListIter.rev(self)
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local inc = self._head < self._tail and 1 or -1
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self._head, self._tail = self._tail - inc, self._head - inc
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return self
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end
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--- Gets the next value in a |list-iterator| without consuming it.
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---
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--- Example:
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---
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--- ```lua
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---
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--- local it = vim.iter({ 3, 6, 9, 12 })
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--- it:peek()
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--- -- 3
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--- it:peek()
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--- -- 3
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--- it:next()
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--- -- 3
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---
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--- ```
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---
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---@return any
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---@diagnostic disable-next-line: unused-local
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function Iter.peek(self) -- luacheck: no unused args
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error('peek() requires a list-like table')
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end
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---@private
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function ListIter.peek(self)
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if self._head ~= self._tail then
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return self._table[self._head]
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end
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end
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--- Find the first value in the iterator that satisfies the given predicate.
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---
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--- Advances the iterator. Returns nil and drains the iterator if no value is found.
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---
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--- Examples:
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---
|
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--- ```lua
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---
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--- local it = vim.iter({ 3, 6, 9, 12 })
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--- it:find(12)
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--- -- 12
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---
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--- local it = vim.iter({ 3, 6, 9, 12 })
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--- it:find(20)
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--- -- nil
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---
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--- local it = vim.iter({ 3, 6, 9, 12 })
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--- it:find(function(v) return v % 4 == 0 end)
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--- -- 12
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---
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--- ```
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---
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---@return any
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function Iter.find(self, f)
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if type(f) ~= 'function' then
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local val = f
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f = function(v)
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return v == val
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end
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end
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local result = nil
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|
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--- Use a closure to handle var args returned from iterator
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local function fn(...)
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if select(1, ...) ~= nil then
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if f(...) then
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result = pack(...)
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else
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return true
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end
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end
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end
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|
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while fn(self:next()) do
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end
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return unpack(result)
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end
|
|
|
|
--- Gets the first value in a |list-iterator| that satisfies a predicate, starting from the end.
|
|
---
|
|
--- Advances the iterator. Returns nil and drains the iterator if no value is found.
|
|
---
|
|
--- Examples:
|
|
---
|
|
--- ```lua
|
|
---
|
|
--- local it = vim.iter({ 1, 2, 3, 2, 1 }):enumerate()
|
|
--- it:rfind(1)
|
|
--- -- 5 1
|
|
--- it:rfind(1)
|
|
--- -- 1 1
|
|
---
|
|
--- ```
|
|
---
|
|
---@see Iter.find
|
|
---
|
|
---@return any
|
|
---@diagnostic disable-next-line: unused-local
|
|
function Iter.rfind(self, f) -- luacheck: no unused args
|
|
error('rfind() requires a list-like table')
|
|
end
|
|
|
|
---@private
|
|
function ListIter.rfind(self, f)
|
|
if type(f) ~= 'function' then
|
|
local val = f
|
|
f = function(v)
|
|
return v == val
|
|
end
|
|
end
|
|
|
|
local inc = self._head < self._tail and 1 or -1
|
|
for i = self._tail - inc, self._head, -inc do
|
|
local v = self._table[i]
|
|
if f(unpack(v)) then
|
|
self._tail = i
|
|
return unpack(v)
|
|
end
|
|
end
|
|
self._head = self._tail
|
|
end
|
|
|
|
--- Transforms an iterator to yield only the first n values.
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
--- local it = vim.iter({ 1, 2, 3, 4 }):take(2)
|
|
--- it:next()
|
|
--- -- 1
|
|
--- it:next()
|
|
--- -- 2
|
|
--- it:next()
|
|
--- -- nil
|
|
--- ```
|
|
---
|
|
---@param n integer
|
|
---@return Iter
|
|
function Iter.take(self, n)
|
|
local next = self.next
|
|
local i = 0
|
|
self.next = function()
|
|
if i < n then
|
|
i = i + 1
|
|
return next(self)
|
|
end
|
|
end
|
|
return self
|
|
end
|
|
|
|
---@private
|
|
function ListIter.take(self, n)
|
|
local inc = self._head < self._tail and 1 or -1
|
|
self._tail = math.min(self._tail, self._head + n * inc)
|
|
return self
|
|
end
|
|
|
|
--- "Pops" a value from a |list-iterator| (gets the last value and decrements the tail).
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
--- local it = vim.iter({1, 2, 3, 4})
|
|
--- it:nextback()
|
|
--- -- 4
|
|
--- it:nextback()
|
|
--- -- 3
|
|
--- ```
|
|
---
|
|
---@return any
|
|
---@diagnostic disable-next-line: unused-local
|
|
function Iter.nextback(self) -- luacheck: no unused args
|
|
error('nextback() requires a list-like table')
|
|
end
|
|
|
|
function ListIter.nextback(self)
|
|
if self._head ~= self._tail then
|
|
local inc = self._head < self._tail and 1 or -1
|
|
self._tail = self._tail - inc
|
|
return self._table[self._tail]
|
|
end
|
|
end
|
|
|
|
--- Gets the last value of a |list-iterator| without consuming it.
|
|
---
|
|
--- See also |Iter:last()|.
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
--- local it = vim.iter({1, 2, 3, 4})
|
|
--- it:peekback()
|
|
--- -- 4
|
|
--- it:peekback()
|
|
--- -- 4
|
|
--- it:nextback()
|
|
--- -- 4
|
|
--- ```
|
|
---
|
|
---@return any
|
|
---@diagnostic disable-next-line: unused-local
|
|
function Iter.peekback(self) -- luacheck: no unused args
|
|
error('peekback() requires a list-like table')
|
|
end
|
|
|
|
function ListIter.peekback(self)
|
|
if self._head ~= self._tail then
|
|
local inc = self._head < self._tail and 1 or -1
|
|
return self._table[self._tail - inc]
|
|
end
|
|
end
|
|
|
|
--- Skips `n` values of an iterator pipeline.
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
---
|
|
--- local it = vim.iter({ 3, 6, 9, 12 }):skip(2)
|
|
--- it:next()
|
|
--- -- 9
|
|
---
|
|
--- ```
|
|
---
|
|
---@param n number Number of values to skip.
|
|
---@return Iter
|
|
function Iter.skip(self, n)
|
|
for _ = 1, n do
|
|
local _ = self:next()
|
|
end
|
|
return self
|
|
end
|
|
|
|
---@private
|
|
function ListIter.skip(self, n)
|
|
local inc = self._head < self._tail and n or -n
|
|
self._head = self._head + inc
|
|
if (inc > 0 and self._head > self._tail) or (inc < 0 and self._head < self._tail) then
|
|
self._head = self._tail
|
|
end
|
|
return self
|
|
end
|
|
|
|
--- Skips `n` values backwards from the end of a |list-iterator| pipeline.
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
--- local it = vim.iter({ 1, 2, 3, 4, 5 }):skipback(2)
|
|
--- it:next()
|
|
--- -- 1
|
|
--- it:nextback()
|
|
--- -- 3
|
|
--- ```
|
|
---
|
|
---@param n number Number of values to skip.
|
|
---@return Iter
|
|
---@diagnostic disable-next-line: unused-local
|
|
function Iter.skipback(self, n) -- luacheck: no unused args
|
|
error('skipback() requires a list-like table')
|
|
return self
|
|
end
|
|
|
|
---@private
|
|
function ListIter.skipback(self, n)
|
|
local inc = self._head < self._tail and n or -n
|
|
self._tail = self._tail - inc
|
|
if (inc > 0 and self._head > self._tail) or (inc < 0 and self._head < self._tail) then
|
|
self._head = self._tail
|
|
end
|
|
return self
|
|
end
|
|
|
|
--- Gets the nth value of an iterator (and advances to it).
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
---
|
|
--- local it = vim.iter({ 3, 6, 9, 12 })
|
|
--- it:nth(2)
|
|
--- -- 6
|
|
--- it:nth(2)
|
|
--- -- 12
|
|
---
|
|
--- ```
|
|
---
|
|
---@param n number The index of the value to return.
|
|
---@return any
|
|
function Iter.nth(self, n)
|
|
if n > 0 then
|
|
return self:skip(n - 1):next()
|
|
end
|
|
end
|
|
|
|
--- Gets the nth value from the end of a |list-iterator| (and advances to it).
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
---
|
|
--- local it = vim.iter({ 3, 6, 9, 12 })
|
|
--- it:nthback(2)
|
|
--- -- 9
|
|
--- it:nthback(2)
|
|
--- -- 3
|
|
---
|
|
--- ```
|
|
---
|
|
---@param n number The index of the value to return.
|
|
---@return any
|
|
function Iter.nthback(self, n)
|
|
if n > 0 then
|
|
return self:skipback(n - 1):nextback()
|
|
end
|
|
end
|
|
|
|
--- Sets the start and end of a |list-iterator| pipeline.
|
|
---
|
|
--- Equivalent to `:skip(first - 1):skipback(len - last + 1)`.
|
|
---
|
|
---@param first number
|
|
---@param last number
|
|
---@return Iter
|
|
---@diagnostic disable-next-line: unused-local
|
|
function Iter.slice(self, first, last) -- luacheck: no unused args
|
|
error('slice() requires a list-like table')
|
|
return self
|
|
end
|
|
|
|
---@private
|
|
function ListIter.slice(self, first, last)
|
|
return self:skip(math.max(0, first - 1)):skipback(math.max(0, self._tail - last - 1))
|
|
end
|
|
|
|
--- Returns true if any of the items in the iterator match the given predicate.
|
|
---
|
|
---@param pred function(...):bool Predicate function. Takes all values returned from the previous
|
|
--- stage in the pipeline as arguments and returns true if the
|
|
--- predicate matches.
|
|
function Iter.any(self, pred)
|
|
local any = false
|
|
|
|
--- Use a closure to handle var args returned from iterator
|
|
local function fn(...)
|
|
if select(1, ...) ~= nil then
|
|
if pred(...) then
|
|
any = true
|
|
else
|
|
return true
|
|
end
|
|
end
|
|
end
|
|
|
|
while fn(self:next()) do
|
|
end
|
|
return any
|
|
end
|
|
|
|
--- Returns true if all items in the iterator match the given predicate.
|
|
---
|
|
---@param pred function(...):bool Predicate function. Takes all values returned from the previous
|
|
--- stage in the pipeline as arguments and returns true if the
|
|
--- predicate matches.
|
|
function Iter.all(self, pred)
|
|
local all = true
|
|
|
|
local function fn(...)
|
|
if select(1, ...) ~= nil then
|
|
if not pred(...) then
|
|
all = false
|
|
else
|
|
return true
|
|
end
|
|
end
|
|
end
|
|
|
|
while fn(self:next()) do
|
|
end
|
|
return all
|
|
end
|
|
|
|
--- Drains the iterator and returns the last item.
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
---
|
|
--- local it = vim.iter(vim.gsplit('abcdefg', ''))
|
|
--- it:last()
|
|
--- -- 'g'
|
|
---
|
|
--- local it = vim.iter({ 3, 6, 9, 12, 15 })
|
|
--- it:last()
|
|
--- -- 15
|
|
---
|
|
--- ```
|
|
---
|
|
---@return any
|
|
function Iter.last(self)
|
|
local last = self:next()
|
|
local cur = self:next()
|
|
while cur do
|
|
last = cur
|
|
cur = self:next()
|
|
end
|
|
return last
|
|
end
|
|
|
|
---@private
|
|
function ListIter.last(self)
|
|
local inc = self._head < self._tail and 1 or -1
|
|
local v = self._table[self._tail - inc]
|
|
self._head = self._tail
|
|
return v
|
|
end
|
|
|
|
--- Yields the item index (count) and value for each item of an iterator pipeline.
|
|
---
|
|
--- For list tables, this is more efficient:
|
|
---
|
|
--- ```lua
|
|
--- vim.iter(ipairs(t))
|
|
--- ```
|
|
---
|
|
--- instead of:
|
|
---
|
|
--- ```lua
|
|
--- vim.iter(t):enumerate()
|
|
--- ```
|
|
---
|
|
--- Example:
|
|
---
|
|
--- ```lua
|
|
---
|
|
--- local it = vim.iter(vim.gsplit('abc', '')):enumerate()
|
|
--- it:next()
|
|
--- -- 1 'a'
|
|
--- it:next()
|
|
--- -- 2 'b'
|
|
--- it:next()
|
|
--- -- 3 'c'
|
|
---
|
|
--- ```
|
|
---
|
|
---@return Iter
|
|
function Iter.enumerate(self)
|
|
local i = 0
|
|
return self:map(function(...)
|
|
i = i + 1
|
|
return i, ...
|
|
end)
|
|
end
|
|
|
|
---@private
|
|
function ListIter.enumerate(self)
|
|
local inc = self._head < self._tail and 1 or -1
|
|
for i = self._head, self._tail - inc, inc do
|
|
local v = self._table[i]
|
|
self._table[i] = pack(i, v)
|
|
end
|
|
return self
|
|
end
|
|
|
|
--- Creates a new Iter object from a table or other |iterable|.
|
|
---
|
|
---@param src table|function Table or iterator to drain values from
|
|
---@return Iter
|
|
---@private
|
|
function Iter.new(src, ...)
|
|
local it = {}
|
|
if type(src) == 'table' then
|
|
local mt = getmetatable(src)
|
|
if mt and type(mt.__call) == 'function' then
|
|
---@private
|
|
function it.next()
|
|
return src()
|
|
end
|
|
|
|
setmetatable(it, Iter)
|
|
return it
|
|
end
|
|
|
|
local t = {}
|
|
|
|
-- O(n): scan the source table to decide if it is a list (consecutive integer indices 1…n).
|
|
local count = 0
|
|
for _ in pairs(src) do
|
|
count = count + 1
|
|
local v = src[count]
|
|
if v == nil then
|
|
return Iter.new(pairs(src))
|
|
end
|
|
t[count] = v
|
|
end
|
|
return ListIter.new(t)
|
|
end
|
|
|
|
if type(src) == 'function' then
|
|
local s, var = ...
|
|
|
|
--- Use a closure to handle var args returned from iterator
|
|
local function fn(...)
|
|
-- Per the Lua 5.1 reference manual, an iterator is complete when the first returned value is
|
|
-- nil (even if there are other, non-nil return values). See |for-in|.
|
|
if select(1, ...) ~= nil then
|
|
var = select(1, ...)
|
|
return ...
|
|
end
|
|
end
|
|
|
|
---@private
|
|
function it.next()
|
|
return fn(src(s, var))
|
|
end
|
|
|
|
setmetatable(it, Iter)
|
|
else
|
|
error('src must be a table or function')
|
|
end
|
|
return it
|
|
end
|
|
|
|
--- Create a new ListIter
|
|
---
|
|
---@param t table List-like table. Caller guarantees that this table is a valid list.
|
|
---@return Iter
|
|
---@private
|
|
function ListIter.new(t)
|
|
local it = {}
|
|
it._table = t
|
|
it._head = 1
|
|
it._tail = #t + 1
|
|
setmetatable(it, ListIter)
|
|
return it
|
|
end
|
|
|
|
--- Collects an |iterable| into a table.
|
|
---
|
|
--- ```lua
|
|
--- -- Equivalent to:
|
|
--- vim.iter(f):totable()
|
|
--- ```
|
|
---
|
|
---@param f function Iterator function
|
|
---@return table
|
|
function M.totable(f, ...)
|
|
return Iter.new(f, ...):totable()
|
|
end
|
|
|
|
--- Filters a table or other |iterable|.
|
|
---
|
|
--- ```lua
|
|
--- -- Equivalent to:
|
|
--- vim.iter(src):filter(f):totable()
|
|
--- ```
|
|
---
|
|
---@see |Iter:filter()|
|
|
---
|
|
---@param f function(...):bool Filter function. Accepts the current iterator or table values as
|
|
--- arguments and returns true if those values should be kept in the
|
|
--- final table
|
|
---@param src table|function Table or iterator function to filter
|
|
---@return table
|
|
function M.filter(f, src, ...)
|
|
return Iter.new(src, ...):filter(f):totable()
|
|
end
|
|
|
|
--- Maps a table or other |iterable|.
|
|
---
|
|
--- ```lua
|
|
--- -- Equivalent to:
|
|
--- vim.iter(src):map(f):totable()
|
|
--- ```
|
|
---
|
|
---@see |Iter:map()|
|
|
---
|
|
---@param f function(...):?any Map function. Accepts the current iterator or table values as
|
|
--- arguments and returns one or more new values. Nil values are removed
|
|
--- from the final table.
|
|
---@param src table|function Table or iterator function to filter
|
|
---@return table
|
|
function M.map(f, src, ...)
|
|
return Iter.new(src, ...):map(f):totable()
|
|
end
|
|
|
|
---@type IterMod
|
|
return setmetatable(M, {
|
|
__call = function(_, ...)
|
|
return Iter.new(...)
|
|
end,
|
|
})
|