Unusual Expressions
Start Quantum again and reproduce what you see in the Quantum session below.
Quantum objects,
_I
and
_Infinity, although they might look like
Symbol's, are actually a
Complex
and an
Infinity. This is because
Read
treats
_I
and
_Infinity
as exceptions. Expression
()
is an empty
Expr. Expressions
'f
and
`f
are sugar-coated syntax for
(Quote f)
and
(Bquote f)
. Symbols with funny print names have their names delimited by
|
characters. The
\
character is an "escape character" in
String's and
Char's. Escape sequences
\\,
\n,
\r,
\',
\"
inside
String's and
Char's
are converted to backslash, newline, return, quote, and double quote characters.
If you like C programming language strings, you will like Quantum
String's.
Complex
and
Infinity
numbers Print
like
Expr's, but they are not
Expr's.
The good news is they
Print
like
Expr's which when
Read
back in, and
Evaluated,
produce numbers equal to those you
Printed. The bad news is the
Printed representation for
Complex
and
Infinity
numbers is somewhat misleading. For example, you cannot
Subst
into a
Complex
number because a
Complex
is in reality an atom, not an
Expr.
|
