print and read cornercase

[Danilo Kordic]

: (setq v1 (intern "12"))
-> 12
: # I expected \1\2
: (sym? v1)
-> T
: (setq v2 \1\2)
-> 12
: (sym? v2)
-> NIL
: # I expected a symbol.
: (num? v2)
-> 12