Added import global syntax.

Author: pigpigyyy

doc/docs/doc/README.md

@@ -928,6 +928,43 @@ tb =
 
 The import statement is a syntax sugar for requiring a module or help extracting items from an imported module. The imported items are const by default.
 
+#### Import Global
+
+You can place `import global` at the top of a block to automatically import all names that have not been explicitly declared or assigned in the current scope as globals. These implicit imports are treated as local consts that reference the corresponding globals at the position of the statement.
+
+Names that are explicitly declared as globals in the same scope will not be imported, so you can safely assign to them.
+
+```moonscript
+do
+  import global
+  print "hello"
+  math.random 3
+  -- print = nil -- error: imported globals are const
+
+do
+  -- explicit global variable will not be imported
+  import global
+  global FLAG
+  print FLAG
+  FLAG = 123
+```
+<YueDisplay>
+<pre>
+do
+  import global
+  print "hello"
+  math.random 3
+  -- print = nil -- error: imported globals are const
+
+do
+  -- explicit global variable will not be imported
+  import global
+  global FLAG
+  print FLAG
+  FLAG = 123
+</pre>
+</YueDisplay>
+
 ```moonscript
 -- used as table destructuring
 do

doc/docs/zh/doc/README.md

@@ -926,6 +926,43 @@ tb =
 
 导入语句是一个语法糖，用于需要引入一个模块或者从已导入的模块中提取子项目。从模块导入的变量默认为不可修改的常量。
 
+#### 导入全局变量
+
+在代码块顶部写 `import global`，会将当前作用域中尚未显式声明或赋值过的变量名，自动导入为本地常量，并在该语句的位置绑定到同名的全局变量。
+
+但是在同一作用域中被显式声明为全局的变量不会被自动导入，因此可以继续进行赋值操作。
+
+```moonscript
+do
+  import global
+  print "hello"
+  math.random 3
+  -- print = nil -- 报错：自动导入的全局变量为常量
+
+do
+  -- 被显式声明为全局的变量不会被自动导入
+  import global
+  global FLAG
+  print FLAG
+  FLAG = 123
+```
+<YueDisplay>
+<pre>
+do
+  import global
+  print "hello"
+  math.random 3
+  -- print = nil -- 报错：自动导入的全局变量是常量
+
+do
+  -- 被显式声明为全局的变量不会被自动导入
+  import global
+  global FLAG
+  print FLAG
+  FLAG = 123
+</pre>
+</YueDisplay>
+
 ```moonscript
 -- 用作表解构
 do

spec/inputs/import_global.yue

@@ -0,0 +1,86 @@
+
+do
+	import global
+	print "hello"
+	math.random 10
+
+do
+	import global
+	value = 1
+	value += 2
+	print value
+
+do
+	local print = (msg) ->
+		return msg
+	do
+		import global
+		print "local"
+		math.random 1
+
+do
+	import global
+	local tostring = (v) -> "local"
+	tostring "value"
+	print tostring 123
+
+do
+	func = (x, y) ->
+		import global
+		return type x, tostring y, print
+	func 1, 2
+
+do
+	import global
+	try
+		func "hello #{world}"
+	catch err
+		print err
+
+do
+	import global
+	global FLAG
+	print FLAG
+	FLAG = 123
+
+do
+	import global
+	global Foo = 10
+	print Foo
+	Foo += 2
+
+do
+	import global
+	global Bar, Baz
+	Bar = 1
+	Baz = 2
+	print Bar, Baz
+
+do
+	import global
+	global *
+	x = 3434
+	if y then
+		x = 10
+
+do
+	import global
+	global ^
+	foobar = "all #{lowercase}"
+	FooBar = "pascal case"
+	FOOBAR = "all #{Uppercase}"
+
+do
+	import global
+	global const class A
+	global const Flag = 1
+	global const const, x, y = "const", 1, 2
+	global const math, table
+	print math, table
+
+do
+	import global
+	with X
+		\func 1, 2, 3
+		.tag = "abc"
+

spec/outputs/codes_from_doc.lua

@@ -408,6 +408,17 @@ local tb = {
 		}
 	}
 }
+do
+	local math = math
+	local print = print
+	print("hello")
+	math.random(3)
+end
+do
+	local print = print
+	print(FLAG)
+	FLAG = 123
+end
 do
 	local insert, concat = table.insert, table.concat
 	local C, Ct, Cmt
@@ -737,36 +748,6 @@ end
 	local first = select(1, ...)
 	return print(ok, count, first)
 end)(fn(true))
-local f
-f = function(...)
-	local t = {
-		n = select("#", ...),
-		...
-	}
-	print("argument count:", t.n)
-	print("table length:", #t)
-	for i = 1, t.n do
-		print(t[i])
-	end
-end
-f(1, 2, 3)
-f("a", "b", "c", "d")
-f()
-local process
-process = function(...)
-	local args = {
-		n = select("#", ...),
-		...
-	}
-	local sum = 0
-	for i = 1, args.n do
-		if args[i] ~= nil and type(args[i]) == "number" then
-			sum = sum + args[i]
-		end
-	end
-	return sum
-end
-process(1, nil, 3, nil, 5)
 Rx.Observable.fromRange(1, 8):filter(function(x)
 	return x % 2 == 0
 end):concat(Rx.Observable.of('who do we appreciate')):map(function(value)
@@ -1000,6 +981,36 @@ local arg1 = {
 	a = 0
 }
 f2(arg1, arg2)
+local f
+f = function(...)
+	local t = {
+		n = select("#", ...),
+		...
+	}
+	print("argument count:", t.n)
+	print("table length:", #t)
+	for i = 1, t.n do
+		print(t[i])
+	end
+end
+f(1, 2, 3)
+f("a", "b", "c", "d")
+f()
+local process
+process = function(...)
+	local args = {
+		n = select("#", ...),
+		...
+	}
+	local sum = 0
+	for i = 1, args.n do
+		if args[i] ~= nil and type(args[i]) == "number" then
+			sum = sum + args[i]
+		end
+	end
+	return sum
+end
+process(1, nil, 3, nil, 5)
 f(function()
 	return print("hello")
 end)
@@ -2916,6 +2927,17 @@ local tb = {
 		}
 	}
 }
+do
+	local math = math
+	local print = print
+	print("hello")
+	math.random(3)
+end
+do
+	local print = print
+	print(FLAG)
+	FLAG = 123
+end
 do
 	local insert, concat = table.insert, table.concat
 	local C, Ct, Cmt
@@ -3245,36 +3267,6 @@ end
 	local first = select(1, ...)
 	return print(ok, count, first)
 end)(fn(true))
-local f
-f = function(...)
-	local t = {
-		n = select("#", ...),
-		...
-	}
-	print("argument count:", t.n)
-	print("table length:", #t)
-	for i = 1, t.n do
-		print(t[i])
-	end
-end
-f(1, 2, 3)
-f("a", "b", "c", "d")
-f()
-local process
-process = function(...)
-	local args = {
-		n = select("#", ...),
-		...
-	}
-	local sum = 0
-	for i = 1, args.n do
-		if args[i] ~= nil and type(args[i]) == "number" then
-			sum = sum + args[i]
-		end
-	end
-	return sum
-end
-process(1, nil, 3, nil, 5)
 Rx.Observable.fromRange(1, 8):filter(function(x)
 	return x % 2 == 0
 end):concat(Rx.Observable.of('who do we appreciate')):map(function(value)
@@ -3538,6 +3530,36 @@ findFirstEven = function(list)
 	end
 	return nil
 end
+local f
+f = function(...)
+	local t = {
+		n = select("#", ...),
+		...
+	}
+	print("argument count:", t.n)
+	print("table length:", #t)
+	for i = 1, t.n do
+		print(t[i])
+	end
+end
+f(1, 2, 3)
+f("a", "b", "c", "d")
+f()
+local process
+process = function(...)
+	local args = {
+		n = select("#", ...),
+		...
+	}
+	local sum = 0
+	for i = 1, args.n do
+		if args[i] ~= nil and type(args[i]) == "number" then
+			sum = sum + args[i]
+		end
+	end
+	return sum
+end
+process(1, nil, 3, nil, 5)
 f(function()
 	return print("hello")
 end)