common lisp symbol matching - lisp

Question

I have an alist in the following form:
((|* bank accounts| (|account 1| |account 2|))
(|* airline miles| (|account 1| |account 2|))
.....
.....)
I don't how to use assoc to access the symbols, since they're framed on both sides with "|".

Answer 1

Quoted symbols are treated like any other symbol, but the string case of the symbol is preserved:
(assoc '|foo bar| '((|baz| . 1) (|foo bar| . 2))) => (|foo bar| . 2)
Here are some more examples (with standard reader case settings):
(intern "foo bar") => |foo bar|
(intern "Foo") => |Foo|
(intern "FOO") => FOO
A longer answer can be found on cliki. Please also refer to 2.3.4 Symbols as Tokens in the Common Lisp Hyperspec.

Answer 2

The same way they are printed:
> (defparameter *alist*
'((|* bank accounts| |account 1| |account 2|)
(|* airline miles| |account 1| |account 2|)))
*ALIST*
> (cdr (assoc '|* bank accounts| *alist*))
(|account 1| |account 2|)
> (cdr (assoc '|* airline miles| *alist*))
(|account 1| |account 2|)
The vertical-bars are just multiple escape characters allowing the use of characters which the standard reader wouldn't read as a symbol. For example, whitespace would result in separate symbols in standard reader syntax:
> (read-from-string "foo bar")
FOO ;
4
Numbers won't yield a symbol:
> (read-from-string "123 456")
123 ;
4
> (type-of *)
(INTEGER 0 16777215)
Without escaping, and the default readtable-case, the read symbols would be in upper case:
> 'foo
FOO
But:
> (intern "1234")
|1234| ;
NIL
> (type-of *)
SYMBOL
> '|foo bar baz|
|foo bar baz|
> (symbol-name *)
"foo bar baz"