Syntax for symbols is more permissive than R6RS

[Mike Gran]

Hi,

I was poking around the reader while working on the Unicode stuff, and I
found that there aren't checks for a lot of symbol names that R6RS
considers to be invalid.

The following line has 11 dodgy but not invalid variable names:

+  -  ...  00A  @  [  \  ]  {  |  } 

They can be strung together to make fun code like this:
(define - 1)
(define [ 2)
(define ] 3)
(+ 1 [ - 2 3 ])
==> 12

Which of these are useful extensions and which of these are bugs?

Thanks,

Mike Gran