Red PL do with block

The Red programming language is moving slowly to version 1.0 and today is at 0.5.4

I thought that it might be useful to look at a do block with the prin function when entered at the Red console.

My example is as follows:

do [
  t1: "test1"
  prin t1
  t1: "test2"
  prin t1
]

The console output will be

test1test2

and NOT

test2test2

Why?

I think that this is only really clear if you see the example code as

do [
  t1: "test1"
  prin :t1
  t1: "test2"
  prin :t1
]

The difference above is that each prin function explicitly is being passed the value of t1.

This is what happens in the short-hand or syntactic sugar version of the example as I first presented it.

If a new user of Red imagined that prin was being passed the ADDRESS of t1 or the ADDRESS of its value, one might expect the meta-level do block to output

test2test2.

This is obvious to old-hands from Rebol, but it may not be obvious to users who are new to expression-based languages.