From e35ff7371f4a61621587744a7620200380abbbe9 Mon Sep 17 00:00:00 2001
From: Hirokazu Hata <h.hata.ai.t@gmail.com>
Date: Mon, 2 Mar 2020 16:38:43 +0900
Subject: [PATCH] lua: add vim.tbl_len() #11889

---
 runtime/lua/vim/shared.lua       | 18 +++++++++
 test/functional/lua/vim_spec.lua | 63 ++++++++++++--------------------
 2 files changed, 41 insertions(+), 40 deletions(-)

diff --git a/runtime/lua/vim/shared.lua b/runtime/lua/vim/shared.lua
index 498992aa2e..1bf1c63fd7 100644
--- a/runtime/lua/vim/shared.lua
+++ b/runtime/lua/vim/shared.lua
@@ -356,6 +356,24 @@ function vim.tbl_islist(t)
   end
 end
 
+--- Counts the number of non-nil values in table `t`.
+---
+--- <pre>
+--- vim.tbl_count({ a=1, b=2 }) => 2
+--- vim.tbl_count({ 1, 2 }) => 2
+--- </pre>
+---
+--@see https://github.com/Tieske/Penlight/blob/master/lua/pl/tablex.lua
+--@param Table
+--@returns Number that is the number of the value in table
+function vim.tbl_count(t)
+  vim.validate{t={t,'t'}}
+
+  local count = 0
+  for _ in pairs(t) do count = count + 1 end
+  return count
+end
+
 --- Trim whitespace (Lua pattern "%s") from both sides of a string.
 ---
 --@see https://www.lua.org/pil/20.2.html
diff --git a/test/functional/lua/vim_spec.lua b/test/functional/lua/vim_spec.lua
index 532368c37c..5ce4bf2973 100644
--- a/test/functional/lua/vim_spec.lua
+++ b/test/functional/lua/vim_spec.lua
@@ -315,10 +315,7 @@ describe('lua stdlib', function()
       local a = { x = { 1, 2 }, y = 5}
       local b = vim.deepcopy(a)
 
-      local count = 0
-      for _ in pairs(b) do count = count + 1 end
-
-      return b.x[1] == 1 and b.x[2] == 2 and b.y == 5 and count == 2
+      return b.x[1] == 1 and b.x[2] == 2 and b.y == 5 and vim.tbl_count(b) == 2
              and tostring(a) ~= tostring(b)
     ]]))
 
@@ -326,31 +323,22 @@ describe('lua stdlib', function()
       local a = {}
       local b = vim.deepcopy(a)
 
-      local count = 0
-      for _ in pairs(b) do count = count + 1 end
-
-      return vim.tbl_islist(b) and count == 0 and tostring(a) ~= tostring(b)
+      return vim.tbl_islist(b) and vim.tbl_count(b) == 0 and tostring(a) ~= tostring(b)
     ]]))
 
     ok(exec_lua([[
       local a = vim.empty_dict()
       local b = vim.deepcopy(a)
 
-      local count = 0
-      for _ in pairs(b) do count = count + 1 end
-
-      return not vim.tbl_islist(b) and count == 0
+      return not vim.tbl_islist(b) and vim.tbl_count(b) == 0
     ]]))
 
     ok(exec_lua([[
       local a = {x = vim.empty_dict(), y = {}}
       local b = vim.deepcopy(a)
 
-      local count = 0
-      for _ in pairs(b) do count = count + 1 end
-
       return not vim.tbl_islist(b.x) and vim.tbl_islist(b.y)
-        and count == 2
+        and vim.tbl_count(b) == 2
         and tostring(a) ~= tostring(b)
     ]]))
   end)
@@ -430,10 +418,7 @@ describe('lua stdlib', function()
       local b = {y = 2}
       local c = vim.tbl_extend("keep", a, b)
 
-      local count = 0
-      for _ in pairs(c) do count = count + 1 end
-
-      return c.x == 1 and b.y == 2 and count == 2
+      return c.x == 1 and b.y == 2 and vim.tbl_count(c) == 2
     ]]))
 
     ok(exec_lua([[
@@ -442,10 +427,7 @@ describe('lua stdlib', function()
       local c = {z = 3}
       local d = vim.tbl_extend("keep", a, b, c)
 
-      local count = 0
-      for _ in pairs(d) do count = count + 1 end
-
-      return d.x == 1 and d.y == 2 and d.z == 3 and count == 3
+      return d.x == 1 and d.y == 2 and d.z == 3 and vim.tbl_count(d) == 3
     ]]))
 
     ok(exec_lua([[
@@ -453,10 +435,7 @@ describe('lua stdlib', function()
       local b = {x = 3}
       local c = vim.tbl_extend("keep", a, b)
 
-      local count = 0
-      for _ in pairs(c) do count = count + 1 end
-
-      return c.x == 1 and count == 1
+      return c.x == 1 and vim.tbl_count(c) == 1
     ]]))
 
     ok(exec_lua([[
@@ -464,10 +443,7 @@ describe('lua stdlib', function()
       local b = {x = 3}
       local c = vim.tbl_extend("force", a, b)
 
-      local count = 0
-      for _ in pairs(c) do count = count + 1 end
-
-      return c.x == 3 and count == 1
+      return c.x == 3 and vim.tbl_count(c) == 1
     ]]))
 
     ok(exec_lua([[
@@ -475,10 +451,7 @@ describe('lua stdlib', function()
       local b = {}
       local c = vim.tbl_extend("keep", a, b)
 
-      local count = 0
-      for _ in pairs(c) do count = count + 1 end
-
-      return not vim.tbl_islist(c) and count == 0
+      return not vim.tbl_islist(c) and vim.tbl_count(c) == 0
     ]]))
 
     ok(exec_lua([[
@@ -486,10 +459,7 @@ describe('lua stdlib', function()
       local b = vim.empty_dict()
       local c = vim.tbl_extend("keep", a, b)
 
-      local count = 0
-      for _ in pairs(c) do count = count + 1 end
-
-      return vim.tbl_islist(c) and count == 0
+      return vim.tbl_islist(c) and vim.tbl_count(c) == 0
     ]]))
 
     eq('Error executing lua: .../shared.lua: invalid "behavior": nil',
@@ -511,6 +481,19 @@ describe('lua stdlib', function()
     )
   end)
 
+  it('vim.tbl_count', function()
+    eq(0, exec_lua [[ return vim.tbl_count({}) ]])
+    eq(0, exec_lua [[ return vim.tbl_count(vim.empty_dict()) ]])
+    eq(0, exec_lua [[ return vim.tbl_count({nil}) ]])
+    eq(0, exec_lua [[ return vim.tbl_count({a=nil}) ]])
+    eq(1, exec_lua [[ return vim.tbl_count({1}) ]])
+    eq(2, exec_lua [[ return vim.tbl_count({1, 2}) ]])
+    eq(2, exec_lua [[ return vim.tbl_count({1, nil, 3}) ]])
+    eq(1, exec_lua [[ return vim.tbl_count({a=1}) ]])
+    eq(2, exec_lua [[ return vim.tbl_count({a=1, b=2}) ]])
+    eq(2, exec_lua [[ return vim.tbl_count({a=1, b=nil, c=3}) ]])
+  end)
+
   it('vim.deep_equal', function()
     eq(true, exec_lua [[ return vim.deep_equal({a=1}, {a=1}) ]])
     eq(true, exec_lua [[ return vim.deep_equal({a={b=1}}, {a={b=1}}) ]])