Added assignment expression for switch syntax.

Author: pigpigyyy

doc/docs/doc/README.md

@@ -2696,28 +2696,26 @@ reader\parse_line! until reader\eof!
 
 ## Switch
 
-The switch statement is shorthand for writing a series of if statements that check against the same value. Note that the value is only evaluated once. Like if statements, switches can have an else block to handle no matches. Comparison is done with the == operator.
+The switch statement is shorthand for writing a series of if statements that check against the same value. Note that the value is only evaluated once. Like if statements, switches can have an else block to handle no matches. Comparison is done with the == operator. In switch statement, you can also use assignment expression to store temporary variable value.
 
 ```moonscript
-name = "Dan"
-switch name
+switch name := "Dan"
   when "Robert"
     print "You are Robert"
   when "Dan", "Daniel"
     print "Your name, it's Dan"
   else
-    print "I don't know about your name"
+    print "I don't know about you with name #{name}"
 ```
 <YueDisplay>
 <pre>
-name = "Dan"
-switch name
+switch name := "Dan"
   when "Robert"
     print "You are Robert"
   when "Dan", "Daniel"
     print "Your name, it's Dan"
   else
-    print "I don't know about your name"
+    print "I don't know about you with name #{name}"
 </pre>
 </YueDisplay>
 
@@ -3528,13 +3526,13 @@ In this usage, with can be seen as a special form of the K combinator.
 The expression in the with statement can also be an assignment, if you want to give a name to the expression.
 
 ```moonscript
-with str = "Hello"
+with str := "Hello"
   print "original:", str
   print "upper:", \upper!
 ```
 <YueDisplay>
 <pre>
-with str = "Hello"
+with str := "Hello"
   print "original:", str
   print "upper:", \upper!
 </pre>

doc/docs/zh/doc/README.md

@@ -2655,28 +2655,26 @@ reader\parse_line! until reader\eof!
 
 ## switch 语句
 
-switch语句是为了简化检查一系列相同值的if语句而提供的简写语法。要注意用于比较检查的目标值只会计算一次。和if语句一样，switch语句在最后可以接一个else代码块来处理没有匹配的情况。在生成的Lua代码中，进行比较是使用==操作符完成的。
+switch语句是为了简化检查一系列相同值的if语句而提供的简写语法。要注意用于比较检查的目标值只会计算一次。和if语句一样，switch语句在最后可以接一个else代码块来处理没有匹配的情况。在生成的Lua代码中，进行比较是使用==操作符完成的。switch语句中也可以使用赋值表达式来储存临时变量值。
 
 ```moonscript
-name = "Dan"
-switch name
+switch name := "Dan"
   when "Robert"
     print "你是Robert"
   when "Dan", "Daniel"
     print "你的名字是Dan"
   else
-    print "我不知道你的名字"
+    print "我不认识你，你的名字是#{name}"
 ```
 <YueDisplay>
 <pre>
-name = "Dan"
-switch name
+switch name := "Dan"
   when "Robert"
     print "你是Robert"
   when "Dan", "Daniel"
     print "你的名字是Dan"
   else
-    print "我不知道你的名字"
+    print "我不认识你，你的名字是#{name}"
 </pre>
 </YueDisplay>
 
@@ -3484,13 +3482,13 @@ me = create_person "Leaf", [dad, mother, sister]
 如果你想给表达式另外起一个名称的话，with语句中的表达式也可以是一个赋值语句。
 
 ```moonscript
-with str = "你好"
+with str := "你好"
   print "原始:", str
   print "大写:", \upper!
 ```
 <YueDisplay>
 <pre>
-with str = "你好"
+with str := "你好"
   print "原始:", str
   print "大写:", \upper!
 </pre>

spec/inputs/destructure.yue

@@ -94,7 +94,7 @@ do
 --
 
 do
-	with {a,b} = thing
+	with {a,b} := thing
 		print a, b
 
 

spec/inputs/macro_export.yue

@@ -38,8 +38,8 @@ export macro copy = (src, dst, ...)->
 	"
 do
 	local _src_, _dst_
-	with _dst_ = #{dst}
-		with _src_ = #{src}
+	with _dst_ := #{dst}
+		with _src_ := #{src}
 #{table.concat for field in *{...} do "
 			_dst_.#{field} = _src_.#{field}
 "}"

spec/inputs/switch.yue

@@ -220,4 +220,56 @@ do
 			]
 			print "matched", sixth
 
-nil
+do
+	switch v := "hello"
+		when "hello"
+			print "matched hello"
+		else
+			print "not matched"
+	-- output: matched hello
+
+do
+	f = -> "ok"
+	switch val := f!
+		when "ok"
+			print "it's ok"
+	-- output: it's ok
+
+
+do
+	g = -> 42
+	switch result := g!
+		when 1, 2
+			print "small"
+		when 42
+			print "life universe everything"
+		else
+			print "other #{result}"
+	-- output: life universe everything
+
+do
+	check = ->
+		if true
+			"yes"
+		else
+			"no"
+
+	switch x := check!
+		when "yes"
+			print "affirmative"
+		else
+			print "negative"
+	-- output: affirmative
+
+do
+	t = (): tb ->
+		tb = {a: 1}
+		tb.a = 2
+
+	switch data := t!
+		when {a: 2}
+			print "matched"
+		else
+			print "not matched"
+
+nil

spec/inputs/unicode/destructure.yue

@@ -84,7 +84,7 @@ do
 --
 
 do
-	with {元素a,元素b} = 东西
+	with {元素a,元素b} := 东西
 		打印 元素a, 元素b
 
 

spec/inputs/unicode/macro_export.yue

@@ -37,8 +37,8 @@ export macro 复制 = (源, 目标, ...)->
 	"
 do
 	local _源_, _目标_
-	with _目标_ = #{目标}
-		with _源_ = #{源}
+	with _目标_ := #{目标}
+		with _源_ := #{源}
 #{table.concat for 字段 in *{...} do "
 			_目标_.#{字段} = _源_.#{字段}
 "}"

spec/inputs/unicode/with.yue

@@ -45,19 +45,19 @@ do
 	with 变量a
 		打印 .世界
 
-	模块 = with _模块 = {}
+	模块 = with _模块 := {}
 		.事物 = "你好"
 
-	with 变量a, 变量b = 东西, 布
+	with 变量a, 变量b := 东西, 布
 		打印 .世界
 
-	变量x = with 变量a, 变量b = 1, 2
+	变量x = with 变量a, 变量b := 1, 2
 		打印 变量a + 变量b
 
-	打印 with 变量a, 变量b = 1, 2
+	打印 with 变量a, 变量b := 1, 2
 		打印 变量a + 变量b
 
-	p = with 你好!.字段x, 世界!.字段y = 1, 2
+	p = with 你好!.字段x, 世界!.字段y := 1, 2
 		打印 变量a + 变量b
 
 --
@@ -68,24 +68,24 @@ do
 		变量x\大写!
 
 do
-	with 变量k = "乔"
+	with 变量k := "乔"
 		打印 \大写!
 
 do
-	with 变量a,变量b,变量c = "", "", ""
+	with 变量a,变量b,变量c := "", "", ""
 		打印 \大写!
 
 do
 	变量a = "床铺"
-	with 变量a,变量b,变量c = "", "", ""
+	with 变量a,变量b,变量c := "", "", ""
 		打印 \大写!
 
 do
 	with 变量j
 		打印 \大写!
 
 do
-	with 变量k.变量j = "乔"
+	with 变量k.变量j := "乔"
 		打印 \大写!
 
 do
@@ -96,7 +96,7 @@ do
 
 do
 	with 变量a
-		with .b = 2
+		with .b := 2
 			打印 .c
 
 do
@@ -131,12 +131,12 @@ do
 
 do
 	global 掩码
-	with? 掩码 = 实心矩形 宽: w, 高: h, 颜色: 0x66000000
+	with? 掩码 := 实心矩形 宽: w, 高: h, 颜色: 0x66000000
 		.触摸启用 = true
 		.吞噬触摸 = true
 
 do
-	with? 掩码 = 实心矩形 宽: w, 高: h, 颜色: 0x66000000
+	with? 掩码 := 实心矩形 宽: w, 高: h, 颜色: 0x66000000
 		.触摸启用 = true
 		.吞噬触摸 = true
 

spec/inputs/with.yue

@@ -48,21 +48,21 @@ do
 	with a -- only one value allowed
 		print .world
 
-	mod = with _M = {}
+	mod = with _M := {}
 		.Thing = "hi"
 
 	-- operate on a only
-	with a, b = something, pooh
+	with a, b := something, pooh
 		print .world
 
-	x = with a, b = 1, 2
+	x = with a, b := 1, 2
 		print a + b
 
-	print with a, b = 1, 2
+	print with a, b := 1, 2
 		print a + b
 
 	-- assignment lhs must be evaluated in the order they appear
-	p = with hello!.x, world!.y = 1, 2
+	p = with hello!.x, world!.y := 1, 2
 		print a + b
 
 --
@@ -73,24 +73,24 @@ do
 		x\upper!
 
 do
-	with k = "jo"
+	with k := "jo"
 		print \upper!
 
 do
-	with a,b,c = "", "", ""
+	with a,b,c := "", "", ""
 		print \upper!
 
 do
 	a = "bunk"
-	with a,b,c = "", "", ""
+	with a,b,c := "", "", ""
 		print \upper!
 
 do
 	with j
 		print \upper!
 
 do
-	with k.j = "jo"
+	with k.j := "jo"
 		print \upper!
 
 do
@@ -103,7 +103,7 @@ do
 do
 	with a
 		-- nested `with`s with assignments should change the scope correctly
-		with .b = 2
+		with .b := 2
 			print .c
 
 do
@@ -138,12 +138,12 @@ do
 
 do
 	global mask
-	with? mask = SolidRect width: w, height: h, color: 0x66000000
+	with? mask := SolidRect width: w, height: h, color: 0x66000000
 		.touchEnabled = true
 		.swallowTouches = true
 
 do
-	with? mask = SolidRect width: w, height: h, color: 0x66000000
+	with? mask := SolidRect width: w, height: h, color: 0x66000000
 		.touchEnabled = true
 		.swallowTouches = true
 

spec/outputs/codes_from_doc.lua

@@ -1234,7 +1234,7 @@ if "Robert" == name then
 elseif "Dan" == name or "Daniel" == name then
 	print("Your name, it's Dan")
 else
-	print("I don't know about your name")
+	print("I don't know about you with name " .. tostring(name))
 end
 local b = 1
 local next_number
@@ -3450,7 +3450,7 @@ if "Robert" == name then
 elseif "Dan" == name or "Daniel" == name then
 	print("Your name, it's Dan")
 else
-	print("I don't know about your name")
+	print("I don't know about you with name " .. tostring(name))
 end
 local b = 1
 local next_number