On Wed, Jun 30, 2010 at 6:11 AM, R.. Kumar 1.9.1 OSX <sentinel1879 / gmail.com > wrote: > /opt/local/lib/ruby1.9/1.9.1/pathname.rb:270: warning: `*' interpreted > as argument prefix > > > I keep getting this. I am including highline, sqlite3 and arrayfields in > my code. > > I am using ruby -w inside my code. > > ruby 1.9.1p376 (2009-12-07 revision 26041) [i386-darwin10] > Mac OSX Intel (Snow leopard). > > I get this when running the examples in highline also. > -- > Posted via http://www.ruby-forum.com/. > > It is a warning to let you know that it considers what you typed to be ambiguous, and it is concerned that the way it interprets your code may not be what you intended ary = [ 10 , 20 , 30 ] ary.first * 2 # => 20 (ary.first) * 2 # => 20 (ary.first) * (2) # => 20 (ary.first * 2) # => 20 (ary.first * 2) # => 20 ary.first.*(2) # => 20 ary.first *2 # => [10, 20] # !> `*' interpreted as argument prefix ary.first *[2] # => [10, 20] # !> `*' interpreted as argument prefix ary.first(*[2]) # => [10, 20] ary.first(*2) # => [10, 20] ary.first(2) # => [10, 20] ary.first 2 # => [10, 20] In particular notice the first from each set ary.first * 2 # => 20 ary.first *2 # => [10, 20] # !> `*' interpreted as argument prefix ----- In your particular case, it sees: # Return a pathname which is substituted by String#sub. def sub(pattern, *rest, &block) if block path = @path.sub(pattern, *rest) {|*args| begin old = Thread.current[:pathname_sub_matchdata] Thread.current[:pathname_sub_matchdata] = $~ eval("$~ = Thread.current[:pathname_sub_matchdata]", block.binding) ensure Thread.current[:pathname_sub_matchdata] = old end yield *args } else path = @path.sub(pattern, *rest) end self.class.new(path) end and it is worried about the ambiguity of yield *args (get the results of the block and multiply it by the variable named args vs take the variable args, invoke the * on it to turn it into a sort of variable argument list, and then pass those arguments to in to the block) Anyway, if it bothers you, you can go put parens around it so it becomes yield(*args) and is not ambiguous. But you don't need to worry about it, look where it got those args from: path = @path.sub(pattern, *rest) {|*args| So it is recursively invoking itself, passing the args through the calls, clearly the author did want it to be interpreted this way. ----- Note: can anyone explain to me what unary * is? I looked in the Pickaxe page 333, and don't see it listed with the other operators. I tried defining *@ as an instance method, and I couldn't define it. I tried locating the method 2.method('*@') and it was undefined. I tried looking at parse.y, and found tSTAR mlhs_node { $$ = NEW_MASGN(0, $2); } which I suspect defines the interpreter match for it, but couldn't figure out how to then determine what happens with this. What is it / where did it come from (is it an object?)