Nil - Revision history

Ximan at 02:58, 2 November 2010

2010-11-02T02:58:06Z

Ximan at 02:48, 2 November 2010

2010-11-02T02:48:50Z

Ximan at 02:46, 2 November 2010

2010-11-02T02:46:54Z

Ximan: Created page with "nil is a lua keyword and valid value and specifies something that does not exist. local a = 1 a = a + b --> 'Error: attempt to perform arithmetic on global 'b' (a nil val..."

2010-11-02T02:46:31Z

Created page with "nil is a lua keyword and valid value and specifies something that does not exist. local a = 1 a = a + b --> 'Error: attempt to perform arithmetic on global 'b' (a nil val..."

New page

nil is a lua keyword and valid value and specifies something that does not exist.

local a = 1
a = a + b

--> 'Error: attempt to perform arithmetic on global 'b' (a nil value)'

If no value has been assigned to a variable, then it is of type 'nil'.

local a
print(type(a))

--> 'nil'

If a function call returns no results and yet it is assigned to a variable, that variable is still [[nil]]. If a function returns fewer results than available assignment variables, the extra variables are set to nil.

local f = function() return 1,2 end
local a,b,c = 1,1,1
a,b,c = f()
print(type(c))

--> 'nil'

← Older revision		Revision as of 02:58, 2 November 2010
Line 23:		Line 23:
	--> 'nil'		--> 'nil'
	--> the value of c was 1, but now it's nil!		--> the value of c was 1, but now it's nil!
		+
		+	Confusingly, nil can be used as a return value.
		+
		+	local f = function return nil end
		+	local a,b,c = 1,1,1
		+	a,b,c = f()
		+	print(type(a))
		+
		+	--> 'nil'
		+
		+	And also as a parameter.
		+
		+	local f = function(any) print(type(any)) end
		+	f()
		+	f(nil)
		+
		+	--> 'nil'
		+	--> 'nil'
		+
		+	== See Also ==
		+
		+	* [[...]]
		+
		+	* [[type]]
		+
		+	* [[tuple]]

@@ Line 19: / Line 19: @@
   a,b,c = f()
   print(type(c))
   --> 'nil'

@@ Line 15: / Line 15: @@
 If a function call returns no results and yet it is assigned to a variable, that variable is still [[nil]].  If a function returns fewer results than available assignment variables, the extra variables are set to nil.
-local f     = function() return 1,2 end
+ local f     = function() return 1,2 end
-  local a,b,c = 1,1,1
+ local a,b,c = 1,1,1
-  a,b,c = f()
+ a,b,c = f()
-  print(type(c))
+ print(type(c))
-  --> 'nil'
+ --> 'nil'