From 6b96122453fda22dc44a581af1d536988c1adf41 Mon Sep 17 00:00:00 2001
From: Gregory Anders <greg@gpanders.com>
Date: Wed, 19 Apr 2023 06:45:56 -0600
Subject: fix(iter): add tag to packed table

If pack() is called with a single value, it does not create a table; it
simply returns the value it is passed. When unpack is called with a
table argument, it interprets that table as a list of values that were
packed together into a table.

This causes a problem when the single value being packed is _itself_ a
table. pack() will not place it into another table, but unpack() sees
the table argument and tries to unpack it.

To fix this, we add a simple "tag" to packed table values so that
unpack() only attempts to unpack tables that have this tag. Other tables
are left alone. The tag is simply the length of the table.
---
 runtime/lua/vim/iter.lua | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

(limited to 'runtime/lua/vim/iter.lua')

diff --git a/runtime/lua/vim/iter.lua b/runtime/lua/vim/iter.lua
index b73c03ba9a..fff7644b6a 100644
--- a/runtime/lua/vim/iter.lua
+++ b/runtime/lua/vim/iter.lua
@@ -28,16 +28,17 @@ end
 
 ---@private
 local function unpack(t)
-  if type(t) == 'table' then
-    return _G.unpack(t)
+  if type(t) == 'table' and t.__n ~= nil then
+    return _G.unpack(t, 1, t.__n)
   end
   return t
 end
 
 ---@private
 local function pack(...)
-  if select('#', ...) > 1 then
-    return { ... }
+  local n = select('#', ...)
+  if n > 1 then
+    return { __n = n, ... }
   end
   return ...
 end
@@ -210,6 +211,12 @@ function Iter.totable(self)
     if args == nil then
       break
     end
+
+    if type(args) == 'table' then
+      -- Removed packed table tag if it exists
+      args.__n = nil
+    end
+
     t[#t + 1] = args
   end
   return t
@@ -218,6 +225,14 @@ end
 ---@private
 function ListIter.totable(self)
   if self._head == 1 and self._tail == #self._table + 1 and self.next == ListIter.next then
+    -- Remove any packed table tags
+    for i = 1, #self._table do
+      local v = self._table[i]
+      if type(v) == 'table' then
+        v.__n = nil
+        self._table[i] = v
+      end
+    end
     return self._table
   end
 
@@ -747,7 +762,7 @@ 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] = { i, v }
+    self._table[i] = pack(i, v)
   end
   return self
 end
-- 
cgit 


From 94894068794dbb99804cda689b6c37e70376c8ca Mon Sep 17 00:00:00 2001
From: Gregory Anders <greg@gpanders.com>
Date: Wed, 19 Apr 2023 07:05:04 -0600
Subject: fix(iter): remove special case totable for map-like tables

This was originally meant as a convenience but prevents possible
functionality. For example:

  -- Get the keys of the table with even values
  local t = { a = 1, b = 2, c = 3, d = 4 }
  vim.iter(t):map(function(k, v)
    if v % 2 == 0 then return k end
  end):totable()

The example above would not work, because the map() function returns
only a single value, and cannot be converted back into a table (there
are many such examples like this).

Instead, to convert an iterator into a map-like table, users can use
fold():

  vim.iter(t):fold({}, function(t, k, v)
    t[k] = v
    return t
  end)
---
 runtime/lua/vim/iter.lua | 67 +++++++++++++++++-------------------------------
 1 file changed, 23 insertions(+), 44 deletions(-)

(limited to 'runtime/lua/vim/iter.lua')

diff --git a/runtime/lua/vim/iter.lua b/runtime/lua/vim/iter.lua
index fff7644b6a..c5d5ef835b 100644
--- a/runtime/lua/vim/iter.lua
+++ b/runtime/lua/vim/iter.lua
@@ -18,14 +18,6 @@ ListIter.__call = function(self)
   return self:next()
 end
 
---- Special case implementations for iterators on non-list tables.
----@class TableIter : Iter
-local TableIter = {}
-TableIter.__index = setmetatable(TableIter, Iter)
-TableIter.__call = function(self)
-  return self:next()
-end
-
 ---@private
 local function unpack(t)
   if type(t) == 'table' and t.__n ~= nil then
@@ -185,10 +177,10 @@ end
 
 --- Collect the iterator into a table.
 ---
---- The resulting table depends on the initial source in the iterator pipeline. List-like tables
---- and function iterators will be collected into a list-like table. If multiple values are returned
---- from the final stage in the iterator pipeline, each value will be included in a table. If a
---- map-like table was used as the initial source, then a map-like table is returned.
+--- The resulting table depends on the initial source in the iterator pipeline.
+--- List-like tables and function iterators will be collected into a list-like
+--- table. If multiple values are returned from the final stage in the iterator
+--- pipeline, each value will be included in a table.
 ---
 --- Examples:
 --- <pre>lua
@@ -199,9 +191,13 @@ end
 --- -- { { 1, 2 }, { 2, 4 }, { 3, 6 } }
 ---
 --- vim.iter({ a = 1, b = 2, c = 3 }):filter(function(k, v) return v % 2 ~= 0 end):totable()
---- -- { a = 1, c = 3 }
+--- -- { { 'a', 1 }, { 'c', 3 } }
 --- </pre>
 ---
+--- The generated table is a list-like table with consecutive, numeric indices.
+--- To create a map-like table with arbitrary keys, use |Iter:fold()|.
+---
+---
 ---@return table
 function Iter.totable(self)
   local t = {}
@@ -239,17 +235,21 @@ function ListIter.totable(self)
   return Iter.totable(self)
 end
 
----@private
-function TableIter.totable(self)
-  local t = {}
-  for k, v in self do
-    t[k] = v
-  end
-  return t
-end
-
 --- Fold an iterator or table into a single value.
 ---
+--- Examples:
+--- <pre>
+--- -- Create a new table with only even values
+--- local t = { a = 1, b = 2, c = 3, d = 4 }
+--- local it = vim.iter(t)
+--- it:filter(function(k, v) return v % 2 == 0 end)
+--- it:fold({}, function(t, k, v)
+---   t[k] = v
+---   return t
+--- end)
+--- -- { b = 2, d = 4 }
+--- </pre>
+---
 ---@generic A
 ---
 ---@param init A Initial value of the accumulator.
@@ -783,7 +783,7 @@ function Iter.new(src, ...)
       count = count + 1
       local v = src[count]
       if v == nil then
-        return TableIter.new(src)
+        return Iter.new(pairs(src))
       end
       t[count] = v
     end
@@ -827,25 +827,4 @@ function ListIter.new(t)
   return it
 end
 
---- Create a new TableIter
----
----@param t table Table to iterate over. For list-like tables, use ListIter.new instead.
----@return Iter
----@private
-function TableIter.new(t)
-  local it = {}
-
-  local index = nil
-  function it.next()
-    local k, v = next(t, index)
-    if k ~= nil then
-      index = k
-      return k, v
-    end
-  end
-
-  setmetatable(it, TableIter)
-  return it
-end
-
 return Iter
-- 
cgit