Array/Colon question

[Michael Lazzaro]

Here's something that I'm still confused about.

We have:

print STDOUT : $a;

as indirect object syntax. The colon means "STDOUT is the object we're operating on." It works everywhere. We also have

for 1..10 : 2 {...}

in which the colon indicates a step operation. The above will iterate through the values 2,4,6,8,10.

My question is, how do you you know when : means step and not indirect object?

For example, I would presume

for @a : 2 {...}

means step through @a by twos. But I would expect

foo @a : 2 {...}

to mean indirect object, calling @a.foo(2,{...})

So how's it know?

MikeL