— test1.rb —
b = 1
puts a if a = b
NameError: undefined local variable or method `a’ for main:Object
— test2.rb —
a = 1 if false
puts defined?(a)
local-variable
###############
Help Me^^
###############
On Aug 18, 2008, at 8:29, Kyung won Cheon wrote:
— test1.rb —
b = 1
puts a if a = bNameError: undefined local variable or method `a’ for main:Object
Parser peculiarity. You can’t use a local variable defined for the
first time in the clause of an inline-if for that statement. Define a
before it reaches that line, or use this instead:
if a = b then puts a end
Hier from Programming Ruby book. Its not exactly for this case, but i
think it gets close :
When Ruby sees a name such as ``a’’ in an expression, it needs to
determine if it is a local variable reference or a call to a method with
no parameters. To decide which is the case, Ruby uses a
heuristic. As Ruby reads a source file, it keeps track of symbols that
have been assigned to. It assumes that these symbols are variables. When
it subsequently comes across a symbol that might be
either a variable or a method call, it checks to see if it has seen a
prior assignment to that symbol. If so, it treats the symbol as a
variable; otherwise it treats it as a method call.
There is also this example down below :
Note that the assignment does not have to be executed—Ruby just has to
have seen it. This program does not raise an error.
a = 1 if false; a
Greets
On Mon, 18 Aug 2008 15:29:04 +0900